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Thread: billions-of-potentially-habitable-planets

  1. #91
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    Quote Originally Posted by George Gaylord Simpson
    The field of Astrobiology stands alone in science as having the sole purpose of justifying the belief that its subject matter exists.
    Yep, Colin .. I'm willing to confess plagiarism .. and, frankly I'm not really too fussed about debating whether he was right, or not. Does this really matter in the end ?

    I think the point he makes in this prose is pretty valid, however.

    I mean, presently, it seems that Astrobiology provides commentary about where life might be found, and under what conditions. Implicit in this commentary, is the affirmation that exo-life exists .. which is fair enough for exploring the optimistic hypothesis, (even though the optimistic hypothesis is not falsifiable in practice, and thus, interestingly, the pessimistic case is unlikely to accumulate supporting evidence at the same rate, if at all, as a direct result of this). Ie: the investigation seems very lopsided.

    So, the 'subject matter' ie: 'exo-life', really is being implicitly justified by means of the accumulation of 'Evidence for exo-life', (as Jeff Root has made clear for us) .. like it or not. Further, I'd imagine that if the field of Astrobiology did not exist, then there would probably be little/no evidence accumulating in support of the pro exo-life hypothesis.

    The conclusion that exo-life exists being a belief, is pretty-well inescapable, as there is clearly no evidence that it does exist.

    That Astrobiology makes no overt attempts to justify the fundamentals of the hypothesis, almost excludes it from 'classical' science and yet, it is not portrayed this way publically. I've seen Chris McKay (for eg) openly admitting this in interviews. The reason cited for not following the traditional scientific process, is simply that it is not possible to move forward with investigating the hypothesis, by taking the traditional 'classical' approach. The point is fair enough.

    Nonetheless, I do find that the subject matter is being implicitly justified, covertly, through accumulation of evidence for the exo-life hypothesis.

    Gaylord-Simpson's words are simply straight-talk and serve as a reminder that Astrobiology really is disconnected from the scientific process, at least in terms of its fundamental tenets.

    Regards

  2. #92
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    Quote Originally Posted by Selfsim View Post
    Yep, Colin .. I'm willing to confess plagiarism .. and, frankly I'm not really too fussed about debating whether he was right, or not. Does this really matter in the end ?
    Does it matter that certain of Simpson's ideas have been falsified?

    I think it matters, in the sense that it can help us understand what falsification means in scientific history.

    I mean, presently, it seems that Astrobiology provides commentary about where life might be found, and under what conditions. Implicit in this commentary, is the affirmation that exo-life exists .. which is fair enough for exploring the optimistic hypothesis, (even though the optimistic hypothesis is not falsifiable in practice, and thus, interestingly, the pessimistic case is unlikely to accumulate supporting evidence at the same rate, if at all, as a direct result of this). Ie: the investigation seems very lopsided.
    You contrast the optimistic hypothesis, that exo-life exists, with the pessimistic case. But why think in terms of just two hypotheses? After all, Simpson's paper is optimistic, in the sense that he thought exo-life likely did exist. However, he was very pessimistic about the chances of human beings ever being able to observe or study it.

    And what about the Rare Earth Hypothesis, which suggests active multicellular life is very rare, while microbial life may be much more common? Would you call that optimistic or pessimistic? It might seem like bad news to a SETI enthusiast, but good news if you happen to be a microbiologist...

    Perhaps it would make more sense to speak of a range of hypotheses that have been developed about how common or rare is life in the universe, and about the feasibility or otherwise of finding examples of it beyond our home planet.

    Many hypotheses (both optimistic and pessimistic) have suggested, and many have been falsified... That is how science moves forward.

    For example, back in 1903 Alfred Russel Wallace put forward the idea that life in the Solar System is only possible in what is called today the Goldilocks zone. He also suggested that life is only possible very near the centre of the Galaxy... The Goldilocks zone hypothesis has not been falsified yet. On the other hand, the galaxy-centre hypothesis was falsified rather thoroughly quite a long time ago.

    That Astrobiology makes no overt attempts to justify the fundamentals of the hypothesis, almost excludes it from 'classical' science and yet, it is not portrayed this way publically. I've seen Chris McKay (for eg) openly admitting this in interviews. The reason cited for not following the traditional scientific process, is simply that it is not possible to move forward with investigating the hypothesis, by taking the traditional 'classical' approach. The point is fair enough.
    Exactly what point was Chris McKay making? Was he saying that, in order to move forward, scientists who study stars and planets sometimes develop hypotheses on the basis of less evidence that would be used by scientists studying things here on Earth?

    If so I'd agree with him.

    For instance, back in 1868 Jules Janssen and Norman Lockyer noticed some odd, unexpected lines in the solar spectrum during an eclipse. Norman Lockyer put forward the hypothesis that the lines were the signature of a hitherto unknown element. He even gave it a name, based on the Greek word for Sun.

    Had any scientist before ever postulated a new element without a laboratory specimen, either of the element itself, or one of its compounds??

    Norman Lockyer's hypothesis turned out to be right, though. Its name is Helium.
    Last edited by Colin Robinson; 2012-Apr-29 at 10:24 AM. Reason: fixed typo

  3. #93
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    Quote Originally Posted by Colin Robinson View Post
    Does it matter that certain of Simpson's ideas have been falsified?

    I think it matters, in the sense that it can help us understand what falsification means in scientific history.
    Why dwell on this one example ? .. (There are plenty of better falsification examples). I'm also dubious about your usage of the term 'falsification' as it pertains to speculative ideas, also.
    Also, I have no idea at what time in history he made his exo-planet detection 'prediction' comment. He died in 1984, and the first detection wasn't until 1992, 8 years after his death ... and at a time just prior to major astronomical technological advances which were surely not foreseeable by a paleontologist .. who was not of a technological background.

    Your term' foreseeable future' is subjective, and thus doesn't serve too well as a criterion for making it a textbook 'falsification' case study, especially around that particular era.

    At the end of the day, it was all just opinion. I personally find debating opinions, to be a quite low-value exercise.

    Quote Originally Posted by Colin Robinson
    You contrast the optimistic hypothesis, that exo-life exists, with the pessimistic case. But why think in terms of just two hypotheses? After all, Simpson's paper is optimistic, in the sense that he thought exo-life likely did exist. However, he was very pessimistic about the chances of human beings ever being able to observe or study it.
    Hair-splitting (??) The only feature distinguishing optimism I can see here, was his opinion that exo-life existed. Everyone's got an opinion … and they don't make a difference to the physical reality at this scale.
    Whether anyone can ever observe or study exo-life, (if it exists), is anyone's guess .. depends on whether the sample is local or remote .. amongst many other issues.

    Quote Originally Posted by Colin Robinson
    And what about the Rare Earth Hypothesis, which suggests active multicellular life is very rare, while microbial life may be much more common? Would you call that optimistic or pessimistic? It might seem like bad news to a SETI enthusiast, but good news if you happen to be a microbiologist…
    Once again … its all just opinion … opinions don't make a difference to physical reality at these scales.
    Also, 'enthusiasts' should take a leaf from the pages of professionals. Professionals doing real science don't really care about the results in advance. They care more about performing good science. 'Good news or bad news', is more about how science is conducted, rather than being about whether their opinions turn out to be right or not !
    Another dimension on this comes from Simpson himself:
    Quote Originally Posted by George Gaylord Simpson
    "I don't think that evolution is supremely important because it is my specialty; it is my specialty because I think it is supremely important."
    Quote Originally Posted by Colin Robinson
    Perhaps it would make more sense to speak of a range of hypotheses that have been developed about how common or rare is life in the universe, and about the feasibility or otherwise of finding examples of it beyond our home planet.

    Many hypotheses (both optimistic and pessimistic) have suggested, and many have been falsified... That is how science moves forward.
    Science moves forward on the basis of independently verifiable, repeatable test results. Perception is subject to opinions. Opinions change .. so do the perceptions. Physical reality is independent of perceptions and opinions.

    Quote Originally Posted by Colin Robinson
    For example, back in 1903 Alfred Russel Wallace put forward the idea that life in the Solar System is only possible in what is called today the Goldilocks zone. He also suggested that life is only possible very near the centre of the Galaxy... The Goldilocks zone hypothesis has not been falsified yet. On the other hand, the galaxy-centre hypothesis was falsified rather thoroughly quite a long time ago.
    I'm dubious about your usage of the term 'falsified' here. 'Unlikely', might seem to be a more appropriate term (??)

    Quote Originally Posted by Colin Robinson
    Exactly what point was Chris McKay making? Was he saying that, in order to move forward, scientists who study stars and planets sometimes develop hypotheses on the basis of less evidence that would be used by scientists studying things here on Earth?

    If so I'd agree with him.
    Actually, he wasn't saying anything about 'moving forward'. In fact the point he was making is that Astrobiologists are mostly wrong about many things. He said that the net effect of being wrong so often, is that they get used to accepting just about anything anyone comes up with. The 'filters' (my word) for ascertaining veracity of anything in Astrobiology have to be dropped, which makes the field more 'open and receptive' to ideas than the classical sciences. He went on to say he thought this was good for newcomers, as they get the sense that they can speak about their new ideas, without fearing the 'mighty wrath' of accountability (my words).
    (This is pathetic, if you ask me .. and it seems that Simpson thought that also).

    Quote Originally Posted by Colin Robinson
    For instance, back in 1868 Jules Janssen and Norman Lockyer noticed some odd, unexpected lines in the solar spectrum during an eclipse. Norman Lockyer put forward the hypothesis that the lines were the signature of a hitherto unknown element. He even gave it a name, based on the Greek word for Sun.

    Had any scientist before ever postulated a new element without a laboratory specimen, either of the element itself, or one of its compounds??

    Norman Lockyer's hypothesis turned out to be right, though. Its name is Helium.
    Yes but this hypothesis was formed on the basis of a huge amount of existing evidence and independently verifiable, repeatable lab experiments. That a particular element may not be known on Earth, in this context, is not a huge leap of faith. The sub-atomic physics he was drawing from, and extrapolating from, was fundamentally deterministic and predictable.
    Life on the other hand, is complex by nature. Its functions are not purely deterministic … if it was, there'd be a cure for every disease and ailment known .. and the cure would work exactly the same way, in every case.
    This is the fundamental differentiator at a biological level, as to why exo-life cannot be predicted.
    … And yet so many seem to 'speculate' that it can be ! Beats me why this is done when there is abundant evidence against doing so ..

    Regards

  4. #94
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    The Chris McKay interview is on Youtube here.

    Its about 45 mins in length. His comment comes in at about the 29:50 mark, and I should point out that he's actually referring to 'Planetary Science' when he makes it ... (not Astrobiology) .. apologies for my error .. I was going by memory in my previous posts.

    Regards

  5. #95
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    Quote Originally Posted by Selfsim View Post
    The Chris McKay interview is on Youtube here.

    Its about 45 mins in length. His comment comes in at about the 29:50 mark, and I should point out that he's actually referring to 'Planetary Science' when he makes it ... (not Astrobiology) .. apologies for my error .. I was going by memory in my previous posts.
    Thank you for supplying that reference. I've just been playing what he says around that 29:50 mark, about planetary scientists like himself often being dead wrong.

    The example he gives is an interesting one: they expected Titan's surface to be largely or completely covered by liquid hydrocarbons, and therefore designed the Huygens lander for a splashdown rather than a landing on a solid surface...

    For those of us (including myself) who are not planetary scientists, it's important to remember that they were right to predict liquid hydrocarbons on the surface of Titan. They were just wrong about how much.

    Very large lakes in the polar regions, but no global ocean...

    As you wrote in your earlier posting...

    Quote Originally Posted by Selfsim View Post
    Professionals doing real science don't really care about the results in advance. They care more about performing good science. 'Good news or bad news', is more about how science is conducted, rather than being about whether their opinions turn out to be right or not !
    Perhaps that's the point Chris McKay was making. When Huygens didn't land on an ocean, people like Chris did not greatly care that their theoretical model of Titan was wrong. They were pleased that Huygens had succeeded in landing and sending back data for them to study.

    Quote Originally Posted by Selfsim View Post
    Science moves forward on the basis of independently verifiable, repeatable test results.
    Yes, "test" is the word. They develop hypotheses, and design repeatable experiments to test them.
    Last edited by Colin Robinson; 2012-May-01 at 10:30 PM. Reason: fixed typo

  6. #96
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    Quote Originally Posted by Selfsim View Post
    I mean, presently, it seems that Astrobiology provides commentary about where life might be found, and under what conditions.
    "Might be found" indicates hypothesis, i.e. it's not conclusive.

    Implicit in this commentary, is the affirmation that exo-life exists .. which is fair enough for exploring the optimistic hypothesis, (even though the optimistic hypothesis is not falsifiable in practice, and thus, interestingly, the pessimistic case is unlikely to accumulate supporting evidence at the same rate, if at all, as a direct result of this). Ie: the investigation seems very lopsided.
    What is an "optimistic hypothesis"? An hypothesis needs only to be consistent and testable ... I don't see where optimism and pessimism fits into this picture. Anyway, the testable hypothesis should be something more complex than simply existence or non-existence of life at a particular location. The hypothesis contains the kinds of processes occurring in the remote biosphere producing observable phenomena. Such a more detailed theory would be falsified if contradictions arise between the observable phenomena as interpreted by the theory.

    So, the 'subject matter' ie: 'exo-life', really is being implicitly justified by means of the accumulation of 'Evidence for exo-life', (as Jeff Root has made clear for us) .. like it or not.
    No ... "exo-life" is not justified by evidence, it is merely supported or corroborated by evidence. There's a huge difference.

    Further, I'd imagine that if the field of Astrobiology did not exist, then there would probably be little/no evidence accumulating in support of the pro exo-life hypothesis.
    Obviously, a field must exist for evidence to be systematically accumulated in that particular field.


    The conclusion that exo-life exists being a belief, is pretty-well inescapable, as there is clearly no evidence that it does exist.
    "Exo-life" is neither a conclusion nor a belief, it's a postulate. A postulate is prior to evidence, so whether there is or is not evidence is irrelevant.


    That Astrobiology makes no overt attempts to justify the fundamentals of the hypothesis, almost excludes it from 'classical' science and yet, it is not portrayed this way publically. I've seen Chris McKay (for eg) openly admitting this in interviews. The reason cited for not following the traditional scientific process, is simply that it is not possible to move forward with investigating the hypothesis, by taking the traditional 'classical' approach. The point is fair enough.

    Nonetheless, I do find that the subject matter is being implicitly justified, covertly, through accumulation of evidence for the exo-life hypothesis.
    What you're saying doesn't make logical sense. While something is still a hypothesis it is not justified. It can only be justified when there is conclusive evidence. Any hypothesis, in any science is by definition not justified. It is illogical to require that an hypothesis be justified before it is justified.

    Gaylord-Simpson's words are simply straight-talk and serve as a reminder that Astrobiology really is disconnected from the scientific process, at least in terms of its fundamental tenets.
    I see no fundamental difference between astrobiology and the rest of science. As long as it has testable logical consequences it's very much like theoretical physics with its theoretical postulates like neutrinos, anti-matter, quarks, Higgs boson, magnetic monopoles, strings etc. Some of these are confirmed but some are not... very much like exo-life.

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    Quote Originally Posted by Selfsim
    I mean, presently, it seems that Astrobiology provides commentary about where life might be found, and under what conditions.
    Quote Originally Posted by Paul Wally View Post
    "Might be found" indicates hypothesis, i.e. it's not conclusive.
    Yep .. its certainly not conclusive .. the 'justification term refers to the way the so-called 'evidence' is used in justifying the exo-life postulate (ie: "Evidence for exo-life"). This is separate from justifying exo-life's existence in the physical universe. None-the-less, in the light of there being no direct evidence in support of exo-life per se, the perception of it becomes real in the community. I call this reality by consensus and it is peculiar to communities of humans (some also call it reality-thru-politics' )

    Quote Originally Posted by Paul Wally
    What is an "optimistic hypothesis"? An hypothesis needs only to be consistent and testable ... I don't see where optimism and pessimism fits into this picture.
    I've used the term 'optimistic' in the sense of referring to the 'optimistic' outlook, which in this case would be that exo-life exists. The pessimistic outlook would be that exo-life does not exist. I'm not too hung up on the words though .. but these particular ones convey the sentiment frequently expressed by those who seem to spend lots of time thinking about exo-life matters .. (and talking it into existence).

    Quote Originally Posted by Paul Wally
    Anyway, the testable hypothesis should be something more complex than simply existence or non-existence of life at a particular location. The hypothesis contains the kinds of processes occurring in the remote biosphere producing observable phenomena. Such a more detailed theory would be falsified if contradictions arise between the observable phenomena as interpreted by the theory.
    So somehow we've swapped from a 'hypothesis' to a 'theory' in the same paragraph ..?...
    I'd also prefer to go with a reworded version of what you wrote .. as follows:
    "The hypothesis might contain the kinds of processes which might occur in a postulated remote biosphere, which may produce observable phenomena consistent with Earth-life biogenic processes. The observation of such phenomena, also does not rule out the possibility that these could also be produce by non-biogenic processes, not included in the initial hypothesis postulates."

    Quote Originally Posted by Paul Wally
    No ... "exo-life" is not justified by evidence, it is merely supported or corroborated by evidence. There's a huge difference.
    Agreed ! Although other posters in this forum practising reality by consensus, might not agree with this.

    Quote Originally Posted by Paul Wally
    Obviously, a field must exist for evidence to be systematically accumulated in that particular field.
    Data exists regardless of whether a 'field' of study exists or not. Why does it become 'evidence' because the field exists, I wonder ?

    Quote Originally Posted by Paul Wally
    "Exo-life" is neither a conclusion nor a belief, it's a postulate. A postulate is prior to evidence, so whether there is or is not evidence is irrelevant.
    Well if there is no evidence then who cares whether we label it a 'postulate' or a 'belief' ... call it a 'thought' or an 'idea' .. I don't care ... but if there is no evidence, then its existence in the physical universe is indeterminate. 'Evidence' is not my word for it anyway. It came from others in this forum, which is why I'm using it.

    Quote Originally Posted by Paul Wally
    What you're saying doesn't make logical sense. While something is still a hypothesis it is not justified. It can only be justified when there is conclusive evidence. Any hypothesis, in any science is by definition not justified. It is illogical to require that an hypothesis be justified before it is justified.
    Hopefully the distinctions of reality-by-consensus, and physical reality will add some clarity to what I'm on about (??) I agree with what your saying from a scientific perspective. There are two levels I'm addressing here simultaneously (ie: consensus reality and scientific (physical) reality).
    Quote Originally Posted by Paul Wally
    I see no fundamental difference between astrobiology and the rest of science. As long as it has testable logical consequences it's very much like theoretical physics with its theoretical postulates like neutrinos, anti-matter, quarks, Higgs boson, magnetic monopoles, strings etc. Some of these are confirmed but some are not... very much like exo-life.
    Fine ... and I absolutely disagree with drawing parallels between astrobiology and the theoretical constructs you mention. In many cases, the above postulations are a logical consequence of direct observations and measurements. This is not so for exo-life postulations. Earth life exists, is independently verifiable, and does not require the existence of exo-life. The presence of certain exo-gases also does not necessarily require the presence of exo-life.

    Earth-life encompasses a much wider range of non-linearly interacting systems, which makes the physics of it fundamentally different from sub-atomic particle behaviours, and we know it. Life is based on macro and micro complex adaptive processes, (and I realise you are very much aware of complex systems and what distinguishes them from deterministic Physical models). The sum of the whole, is not the sum of its parts (unlike particle physics).

    The hypothetical particle models you mention lead to practical outcomes and practical, feasible tests, (with the exception of strings .. I'll get back to that). Where the hypothetical 'exo-life' model is applied to exo-planets/moons at light-year distances, such a test is not practically feasible.

    Strings are supported in rigorous mathematical theoretical 'postdictions' of readily observable phenomena (eg: Newtonian and Maxwellian physics). The supporting theory has a high degree of internal consistency which facilitates specific qualitative descriptions of measurables. It explains observable phenomena like some condensate behaviours. It 'synthesises' quantum gravity, and the other fundamental forces. It provides theoretical descriptions of Entropy conditions applicable to Event Horizons, which is so far, not achievable in other theories.

    Exo-life hypotheses have no such consistency, nor exclusive support for observed phenomena in either pre-, or post-diction capacities. Exo-life hypotheses' primary function (other than sentimental value) is to test whether our Earth-life models are ubiquitous and 'standard', wherever Earth-like conditions prevail elsewhere in the universe. In that sense, the test function is not practically executable in most of the target environments it is hypothesised to exist in, (exo-planets/moons, at light-year distances). They may be executable locally, however.

    Regards

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    Quote Originally Posted by Selfsim View Post
    Yep .. its certainly not conclusive .. the 'justification term refers to the way the so-called 'evidence' is used in justifying the exo-life postulate (ie: "Evidence for exo-life"). This is separate from justifying exo-life's existence in the physical universe. None-the-less, in the light of there being no direct evidence in support of exo-life per se, the perception of it becomes real in the community. I call this reality by consensus and it is peculiar to communities of humans (some also call it reality-thru-politics' )
    If the issue is about public perception then I understand your point, but within the scientific community (if there is such a thing) there cannot be such a "reality consensus" it goes against the very critical nature of scientific discourse.

    I've used the term 'optimistic' in the sense of referring to the 'optimistic' outlook, which in this case would be that exo-life exists. The pessimistic outlook would be that exo-life does not exist. I'm not too hung up on the words though .. but these particular ones convey the sentiment frequently expressed by those who seem to spend lots of time thinking about exo-life matters .. (and talking it into existence).
    But I think you assume that one has to be certain of the actual physical existence of something in order to talk about it. It's useful to lay the conceptual groundwork even before any evidence is found.

    So somehow we've swapped from a 'hypothesis' to a 'theory' in the same paragraph ..?...
    I'd also prefer to go with a reworded version of what you wrote .. as follows:
    "The hypothesis might contain the kinds of processes which might occur in a postulated remote biosphere, which may produce observable phenomena consistent with Earth-life biogenic processes. The observation of such phenomena, also does not rule out the possibility that these could also be produce by non-biogenic processes, not included in the initial hypothesis postulates."
    I used the word "theory" just to accentuate that it's more complex than a singular proposition. Yes, you can reword as you did, but that is just to make sure there is no misunderstanding of the meaning of the word "hypothesis"; that it is tentative and that there are possible alternatives.


    Data exists regardless of whether a 'field' of study exists or not. Why does it become 'evidence' because the field exists, I wonder ?
    I'm not sure I understand your point. Would Rutherford have built his instrument that lead to his discovery of the atomic nucleus if the field of physics didn't exist?

    Well if there is no evidence then who cares whether we label it a 'postulate' or a 'belief' ... call it a 'thought' or an 'idea' .. I don't care ... but if there is no evidence, then its existence in the physical universe is indeterminate. 'Evidence' is not my word for it anyway. It came from others in this forum, which is why I'm using it.
    If it's a postulate then it's possible that it exists but there's no evidence that it does, but when there is evidence then it is a fact. It's important to care about the difference between postulates and facts. The existence of things in the universe is what it is. It's completely independent of what we humans currently take as evidence. Evidence depends on existence not the other way around. So, if there exist billions of inhabited planets in the galaxy then they exist right now as we speak, independently of whether we have evidence or not. The question is then what the best approach is to follow, given only two logical possibilities:
    1) Exo-life exists or
    2) exo-life doesn't exist.
    Which mistake would you rather make?

    Fine ... and I absolutely disagree with drawing parallels between astrobiology and the theoretical constructs you mention. In many cases, the above postulations are a logical consequence of direct observations and measurements.
    How do you draw logical consequences from observations and measurements? You can observe the sun rising every morning but cannot logically deduce from that data that the sun will rise tomorrow. We can make logical deductions from theory yes, e.g. a theory of angular momentum applied to a spinning earth.

    This is not so for exo-life postulations. Earth life exists, is independently verifiable, and does not require the existence of exo-life. The presence of certain exo-gases also does not necessarily require the presence of exo-life.
    While this is all true, it is just stating some obvious facts. It's not scientifically interesting because it doesn't make any testable predictions. To postulate something that might be wrong is more interesting than simple stating the obvious facts. I would rather say that there are universal kinds of processes in this universe that made Earth life possible and therfore it also makes exo-life possible. Interesting questions emerge: What is the nature of these processes? What are the possible variations if Earth life is but a single instance? Are there any tell-tale signs of life elsewhere that are currently observable?

    Earth-life encompasses a much wider range of non-linearly interacting systems, which makes the physics of it fundamentally different from sub-atomic particle behaviours, and we know it. Life is based on macro and micro complex adaptive processes, (and I realise you are very much aware of complex systems and what distinguishes them from deterministic Physical models). The sum of the whole, is not the sum of its parts (unlike particle physics).
    Yes, the particular contents and mathematical tools are different for different fields of science, but I was talking about the general methodology of science that is the same: That of proposing hypotheses and testing it.

    The hypothetical particle models you mention lead to practical outcomes and practical, feasible tests, (with the exception of strings .. I'll get back to that).
    What about the atomic theory? For a long time atoms were just speculation, then it became only a working hypothesis in 19th Century chemistry. More tangible evidence of the existence of atoms only emerged in the early 20th century.

    Where the hypothetical 'exo-life' model is applied to exo-planets/moons at light-year distances, such a test is not practically feasible.
    A model could make practically observable predictions and we could design our instruments to look for the right things. It's the same with physics, postulated particles can have observable effects even though we cannot observe these particles directly, but we design our instruments to be able to observe the macroscopic effects the theory predicts and therefore to test the theory.

    Strings are supported in rigorous mathematical theoretical 'postdictions' of readily observable phenomena (eg: Newtonian and Maxwellian physics). The supporting theory has a high degree of internal consistency which facilitates specific qualitative descriptions of measurables. It explains observable phenomena like some condensate behaviours. It 'synthesises' quantum gravity, and the other fundamental forces. It provides theoretical descriptions of Entropy conditions applicable to Event Horizons, which is so far, not achievable in other theories.
    Now what is needed is exactly the biological analogue of such a theory of everything. A theory is needed that 'postdicts' Earth-life and predicts all other variations of life in the universe.


    Exo-life hypotheses have no such consistency, nor exclusive support for observed phenomena in either pre-, or post-diction capacities. Exo-life hypotheses' primary function (other than sentimental value) is to test whether our Earth-life models are ubiquitous and 'standard', wherever Earth-like conditions prevail elsewhere in the universe. In that sense, the test function is not practically executable in most of the target environments it is hypothesised to exist in, (exo-planets/moons, at light-year distances). They may be executable locally, however.
    I cannot speak about exo-life hypotheses in general, I'm sure there's a wide variety of interesting ideas out there, including the possibility of non-carbon based life-forms. Each hypothesis will have to be treated individually in terms of consistency and testable consequences, and this includes consequences that may be observable currently or in the near future. I don't think you can dismiss these possibilities beforehand. You cannot know beforehand what we will or will not discover, even over light year distances.
    Last edited by Paul Wally; 2012-May-02 at 03:22 PM. Reason: "macroscopic effects"

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    Quote Originally Posted by Paul Wally
    But I think you assume that one has to be certain of the actual physical existence of something in order to talk about it. It's useful to lay the conceptual groundwork even before any evidence is found.
    Definition and constraining the possibilities of what one is thinking about is necessary ... if this is what you mean by 'conceptual groundwork' then I agree. Sometimes this is difficult to find around this forum...

    Quote Originally Posted by Paul Wally
    I used the word "theory" just to accentuate that it's more complex than a singular proposition. Yes, you can reword as you did, but that is just to make sure there is no misunderstanding of the meaning of the word "hypothesis"; that it is tentative and that there are possible alternatives.
    Sure. A theory provides an explanation .. which is likely to be more complex, less tentative, and has several firm bases either in other theory, or observation, or both. The quantitative side also kicks into theory.

    Quote Originally Posted by Paul Wally
    I'm not sure I understand your point. Would Rutherford have built his instrument that lead to his discovery of the atomic nucleus if the field of physics didn't exist?
    Well, it would seem that he arrived at the Rutherford model after a series of Geiger-Marsden experiments, aimed at probing the structure of the atom, which ultimately changed the view of the day from the 'plum-pudding model' of the atom, to a nucleus based model. All this was a direct result of the high deflection of alpha particles observed in these experiments. What role does preconceived dogma play in any of that ?
    The man was experimenting and going from there. His opinions were trivial considerations. He was after the reality of how materials behaved .. irrespective of what 'the field' of Physics had to say about atoms.

    The model was developed gradually from the data. That differs from searching specifically for another instance of something which already exists. The two areas are not the same by any comparison I can envisage.

    Quote Originally Posted by Paul Wally
    If it's a postulate then it's possible that it exists but there's no evidence that it does, but when there is evidence then it is a fact. It's important to care about the difference between postulates and facts. The existence of things in the universe is what it is. It's completely independent of what we humans currently take as evidence. Evidence depends on existence not the other way around. So, if there exist billions of inhabited planets in the galaxy then they exist right now as we speak, independently of whether we have evidence or not. The question is then what the best approach is to follow, given only two logical possibilities:
    1) Exo-life exists or:
    2) exo-life doesn't exist.
    Which mistake would you rather make? [/colour]
    Whilst I broadly agree with the gist of the first part of what you say, there is another 'logical possibility' (your term), which is so often overlooked in these discussions ... and it happens to be the only supportable option .. ie:
    3) It is unknown​ whether exo-life exists, or not ! (Ie: indeterminate).

    Why is this so frequently disregarded ? Following this 'logical possibility' can yield very practical results, and results in way less biased ventures.

    Quote Originally Posted by Paul Wally
    How do you draw logical consequences from observations and measurements? You can observe the sun rising every morning but cannot logically deduce from that data that the sun will rise tomorrow. We can make logical deductions from theory yes, e.g. a theory of angular momentum applied to a spinning earth.
    Deductions ... yes. Deductions are not inferences. All exo-life hypotheses I've encountered are dependent on inference ... not deduction. The distinction being that with inference, the belief in the truth of the premise is necessary .. whereas in deduction, the generalised statement (or Physical Laws) come first, and are used to 'deduce' (or predict) the specific case in question via established theory .. no belief needs to be held as truth, because the Laws are based in physically verifiable evidence .. (as opposed to some wild idea).


    Quote Originally Posted by Paul Wally
    While this is all true, it is just stating some obvious facts. It's not scientifically interesting because it doesn't make any testable predictions. To postulate something that might be wrong is more interesting than simple stating the obvious facts. I would rather say that there are universal kinds of processes in this universe that made Earth life possible and therfore it also makes exo-life possible. Interesting questions emerge: What is the nature of these processes? What are the possible variations if Earth life is but a single instance? Are there any tell-tale signs of life elsewhere that are currently observable?
    Whilst you may not find this approach 'scientifically interesting', it is the honest, (ie: non-belief based), approach ... ie: acknowledge the facts and then see what can be done. What I'm saying is that the mere act of local exploration is what will build real knowledge about exo-life. I've used James Cook's expeditions to look for a non-existent (at the time) hypothesised Northwest Passage and the hypothesised 'Great Southern Continent' as examples. The hypotheses (or theories) of the day were irrelevant. In fact, he falsified all of them. The act of exploration was the only factor which made the difference.

    Its the same as looking for an instance of exo-life, based on the Earth-life model. Looking for so called 'possible biogenic exo-gases' results in inference based conclusions only. Travelling feasible distances, and looking at the appropriate scale level, is the only way to find out ! Even if exo-life isn't present where we can look, then at least we can eliminate that specific habitat and ponder why it wasn't present there. My point is that if we're serious about looking for exo-life ... then take meaningful steps that result in firm conclusions .. rather than ones which are only capable of inference based conclusions, which still end up being about 'my' opinion vs 'your' opinion. (Figuratively speaking .. not personally speaking, that is).

    Quote Originally Posted by Paul Wally
    Yes, the particular contents and mathematical tools are different for different fields of science, but I was talking about the general methodology of science that is the same: That of proposing hypotheses and testing it.
    And exo-life tests are not practically feasible over light-year distances.

    So, in effect, such a hypothesis is not practically testable.
    Why should Astrobiology get away with generating impractical, resource intensive, unfeasible tests, whereas other areas of science cannot ?
    Quote Originally Posted by Paul Wally
    What about the atomic theory? For a long time atoms were just speculation, then it became only a working hypothesis in 19th Century chemistry. More tangible evidence of the existence of atoms only emerged in the early 20th century.
    The evidence emerged because testing resulted in verifiable observational data which led to the nuclear based model. The hypothesis you mention became obsolete in an instant. The hypothesis added no value to the process .. as a matter of fact, it might as well have been a bed-side story for all it ended up being worth !
    Exo-biology tests over light year distances is not practically feasible and therefore leads to nothing more than opinion-based inference. Nothing can be resolved. How does this support scientific progress in the hunt for hypothesised exo-life?
    Quote Originally Posted by Paul Wally
    A model could make practically observable predictions and we could design our instruments to look for the right things. It's the same with physics, postulated particles can have observable effects even though we cannot observe these particles directly, but we design our instruments to be able to observe the macroscopic effects the theory predicts and therefore to test the theory.
    We already have a 'life' theory. The hunt for Earth-like exo-biology is the test for the universality of that theory. The test is not practically feasible for remotely testing for exo-biology, over light year distances.
    Quote Originally Posted by Paul Wally
    Now what is needed is exactly the biological analogue of such a theory of everything. A theory is needed that 'postdicts' Earth-life and predicts all other variations of life in the universe.
    If it is needed, then why not pursue meaningful avenues .. rather than ones which we already know, cannot progress the quest ?
    We already have a 'life' theory. Finding exo-biology allows for the execution of that universality test .. this is not practically feasible over light year distances, nor via inference based conclusions on the presence/absence of exo-gases.
    Quote Originally Posted by Paul Wally
    I cannot speak about exo-life hypotheses in general, I'm sure there's a wide variety of interesting ideas out there, including the possibility of non-carbon based life-forms. Each hypothesis will have to be treated individually in terms of consistency and testable consequences, and this includes consequences that may be observable currently or in the near future. I don't think you can dismiss these possibilities beforehand. You cannot know beforehand what we will or will not discover, even over light year distances.
    If the laws of physics have to be violated it can be dismissed on a theoretical basis. If the practicality of executing the tests is not feasible, then the best one can 'hope' for is more opinion-based debate. Opinion based debates never resolve science issues.

    Regards

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    Quote Originally Posted by Selfsim View Post
    What I'm saying is that the mere act of local exploration is what will build real knowledge about exo-life. I've used James Cook's expeditions to look for a non-existent (at the time) hypothesised Northwest Passage and the hypothesised 'Great Southern Continent' as examples. The hypotheses (or theories) of the day were irrelevant. In fact, he falsified all of them.
    Yes, he falsified those hypotheses. But no, they were not irrelevant. The hypotheses you've mentioned raised questions which the explorer set out to answer, and did answer.

    I recommend you have a look at Karl Popper's studies of the scientific method, such as his book Conjectures and Refutations.

    If a hypothesis raises questions that stimulate research, then it has contributed something to science even if it does get falsified.

    Maybe that is why a serious planetary scientist (and astrobiologist) like Chris McKay is not ashamed to say that the ideas of planetary scientists have often been quite wrong.

    Travelling feasible distances, and looking at the appropriate scale level, is the only way to find out ! Even if exo-life isn't present where we can look, then at least we can eliminate that specific habitat and ponder why it wasn't present there.
    I agree with you that examining possible habitats in the Solar System will be scientifically fruitful, even if it leads to the conclusion that a certain location is not a habitat.

    But to do this at all, we'll need hypotheses about which places in the Solar System might be habitats, how organisms there might function, and how would you find them if they were there...

    That's why we need people like Chris McKay...

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    Quote Originally Posted by Colin Robinson View Post
    Yes, he falsified those hypotheses. But no, they were not irrelevant. The hypotheses you've mentioned raised questions which the explorer set out to answer, and did answer.
    Nonsense ... Cook was despatched by the Admirality to observe the transit of Venus and to see what other lands he could claim for the King. The Northwest Passage expedition was also motivated by the potential for commercial gain. The act of exploration was the means for achieving these goals, and its rewards were more than familiar to the Admirality. It had nothing to do with the geographers' hypotheses !
    The postulated geographical hypotheses were regarded by the Admiralty (and Cook) as laughible .. Cook despised them, because to him, they lied by producing ridiculously inaccurate maps causing unnecessary death and suffering for seafarers.

    Quote Originally Posted by Colin Robinson
    I recommend you have a look at Karl Popper's studies of the scientific method, such as his book Conjectures and Refutations.

    If a hypothesis raises questions that stimulate research, then it has contributed something to science even if it does get falsified.
    Cook's falsification (via detailed recorded observations) was co-incidental and after the fact. 'Twas historians and academics who declared the falsification ... not Cook nor the Admiralty.

    Quote Originally Posted by Colin Robinson
    Maybe that is why a serious planetary scientist (and astrobiologist) like Chris McKay is not ashamed to say that the ideas of planetary scientists have often been quite wrong.
    ... or maybe McKay is just a poor scientist who doesn't realise he's being motivated by fantasies of Star Trek and political lobbying, rather than doing productive science which leads to tangible results?

    Quote Originally Posted by Colin Robinson
    I agree with you that examining possible habitats in the Solar System will be scientifically fruitful, even if it leads to the conclusion that a certain location is not a habitat.

    But to do this at all, we'll need hypotheses about which places in the Solar System might be habitats, how organisms there might function, and how would you find them if they were there...

    That's why we need people like Chris McKay...
    We don't need McKay to do that ! Its been going on for centuries before he turned up !
    The local research in the extremes of Earth environments didn't require McKay to lift a finger !
    This glorification of McKay is beginning to teeter on the edge of pseudoscientific behaviour !

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    Quote Originally Posted by Selfsim View Post
    Nonsense ... Cook was despatched by the Admirality to observe the transit of Venus and to see what other lands he could claim for the King. The Northwest Passage expedition was also motivated by the potential for commercial gain. The act of exploration was the means for achieving these goals, and its rewards were more than familiar to the Admirality. It had nothing to do with the geographers' hypotheses !
    In your posting immediately before this one you wrote of "James Cook's expeditions to look for a non-existent (at the time) hypothesised Northwest Passage and the hypothesised 'Great Southern Continent' ". Now again you use the expression "Northwest Passage expedition". And then you tell us it "had nothing to do" with the hypothesis of a Northwest Passage...

    Where is the nonsense?

    ... or maybe McKay is just a poor scientist who doesn't realise he's being motivated by fantasies of Star Trek and political lobbying, rather than doing productive science which leads to tangible results?
    Do you have empirical evidence to back your hypothesis that McKay is a poor scientist?

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    Quote Originally Posted by Selfsim View Post
    Definition and constraining the possibilities of what one is thinking about is necessary ...
    Why limit your thinking? Thinking about something and thinking that it's true are two different things.

    Well, it would seem that he arrived at the Rutherford model after a series of Geiger-Marsden experiments, aimed at probing the structure of the atom, which ultimately changed the view of the day from the 'plum-pudding model' of the atom, to a nucleus based model. All this was a direct result of the high deflection of alpha particles observed in these experiments. What role does preconceived dogma play in any of that ?
    The man was experimenting and going from there. His opinions were trivial considerations. He was after the reality of how materials behaved .. irrespective of what 'the field' of Physics had to say about atoms.
    You were talking about "existence" of a field. If the field of physics didn't exist how is a complex experiment requiring complex instrumentation even possible in a conceptual vacuum. Rutherford was surprised by his finding, how could he have been surprised if he didn't have some pre-conceived idea that was then falsified? "Conjectures and refutations", that's the process.


    Whilst I broadly agree with the gist of the first part of what you say, there is another 'logical possibility' (your term), which is so often overlooked in these discussions ... and it happens to be the only supportable option .. ie:
    3) It is unknown​ whether exo-life exists, or not ! (Ie: indeterminate).
    Why is this so frequently disregarded ? Following this 'logical possibility' can yield very practical results, and results in way less biased ventures.
    In reality there is only two possibilities, what we know or don't know is not a possibility in the reality out there, it's only in our minds. "We don't know" doesn't exist out there. Reality is not agnostic, it is one way or the other, right now, as we speak. And this whole thing about "biased ventures" just represents a misunderstanding of what it means to hypothesize. If it's not conclusive how can it possibly be biased? This kind of thinking of "biased ventures" seems more applicable to the kinds of statistical methods used in the social and economic sciences; there must be a representative sample space etc etc. Anyway, statistics at best will only give you a phenomenological theory rather than a comprehensive theory based on fundamental and universally applicable principles.

    Deductions ... yes. Deductions are not inferences. All exo-life hypotheses I've encountered are dependent on inference ... not deduction. The distinction being that with inference, the belief in the truth of the premise is necessary .. whereas in deduction, the generalised statement (or Physical Laws) come first, and are used to 'deduce' (or predict) the specific case in question via established theory .. no belief needs to be held as truth, because the Laws are based in physically verifiable evidence .. (as opposed to some wild idea).
    Deduction is the most rigorous form of inference. It is purely logical inference from a premise, irrespective of empirical truth value of the premise. Other forms of inference are inductive inference (generalization from a set of instances) and abductive inference (going from empirical data to an explanation of that empirical data). It is the latter kind of inference that I find most applicable to theoretical progress in both physics and exobiology.

    Whilst you may not find this approach 'scientifically interesting', it is the honest, (ie: non-belief based), approach ... ie: acknowledge the facts and then see what can be done. What I'm saying is that the mere act of local exploration is what will build real knowledge about exo-life. I've used James Cook's expeditions to look for a non-existent (at the time) hypothesised Northwest Passage and the hypothesised 'Great Southern Continent' as examples. The hypotheses (or theories) of the day were irrelevant. In fact, he falsified all of them. The act of exploration was the only factor which made the difference.
    It is equally honest and non-belief based to qualify one's ideas as hypothetical ... but we have been over this numerous times and we're going around in circles. Your example of Jimmy Cook has no application to the issue of exo-life. Since the existence of a hypothetical north-west passage, Australia and New Zealand are completely contingent matters there is no conceivable general theory with which their existence or non-existence could have been predicted. It is quite a different situation with exo-life; it is conceivable that there is theory by which the existence of life under certain conditions could be deduced.

    Its the same as looking for an instance of exo-life, based on the Earth-life model. Looking for so called 'possible biogenic exo-gases' results in inference based conclusions only. Travelling feasible distances, and looking at the appropriate scale level, is the only way to find out ! Even if exo-life isn't present where we can look, then at least we can eliminate that specific habitat and ponder why it wasn't present there. My point is that if we're serious about looking for exo-life ... then take meaningful steps that result in firm conclusions .. rather than ones which are only capable of inference based conclusions, which still end up being about 'my' opinion vs 'your' opinion. (Figuratively speaking .. not personally speaking, that is).
    You keep on wanting either firm conclusions or nothing. I think I've made my point clear on "conclusions" numerous times.

    And exo-life tests are not practically feasible over light-year distances.
    This point I also addressed a few times. You cannot know this a priori.

    So, in effect, such a hypothesis is not practically testable.
    You don't know this.

    Why should Astrobiology get away with generating impractical, resource intensive, unfeasible tests, whereas other areas of science cannot ?
    The resource issue I addressed also. At the moment local planetary exploration is much more resource intensive, not that I have anything against local exploration.

    The evidence emerged because testing resulted in verifiable observational data which led to the nuclear based model. The hypothesis you mention became obsolete in an instant. The hypothesis added no value to the process .. as a matter of fact, it might as well have been a bed-side story for all it ended up being worth !
    Exo-biology tests over light year distances is not practically feasible and therefore leads to nothing more than opinion-based inference. Nothing can be resolved. How does this support scientific progress in the hunt for hypothesised exo-life?
    These are your opinions.

    If it is needed, then why not pursue meaningful avenues .. rather than ones which we already know, cannot progress the quest ?
    We already have a 'life' theory. Finding exo-biology allows for the execution of that universality test .. this is not practically feasible over light year distances, nor via inference based conclusions on the presence/absence of exo-gases.
    If the laws of physics have to be violated it can be dismissed on a theoretical basis. If the practicality of executing the tests is not feasible, then the best one can 'hope' for is more opinion-based debate. Opinion based debates never resolve science issues.
    ... and more opinions.

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    Paul;

    Although this discussion may to have given you the impression that I outright reject hypothesisation in the scientific process, I have already agreed, (elsewhere - in the past), that I recognise and fully acknowledge the role it plays in guiding scientific thinking and modelling. I do not find these views to be shared by other across this forum, however.

    My issue lies in over-emphasing the reality of hypotheses with the view to directly acting upon them. Prioritising a hypothesis based venture and depleting resources away from non-hypotheses based science projects is a growing issue thesedays, (IMO).

    I find over-emphasis on the importance of hypotheses is exactly what is happening in this forum (IMO) .. this being by way of multiple restatement almost to the point of excess. Hypotheses are best handled by those who originate them, and by those empowered within scientific communities, to able to support, reject or moderate them.

    Lobbying in support of scientifically unsupportable hypotheses, to the extent they become reality-by-consensus in the mind of the public, (IMO), is directly at odds with the principles of science … (ie: in-so-far as science being our best tool for distinguishing reality from delusion). This is at the core of my opposition.

    You say I have expressed opinions (in the latter comments on your previous post). I would agree they are indeed opinions (although historically supportable). This is exactly where opinion based hypotheses lead, and why debating opinions, in my view, is a waste of time.

    I'd like to suggest we move on, and discuss more productive matters where the potential for learning and knowledge acquisition abounds, eh ?

    Best Regards
    Last edited by Selfsim; 2012-May-04 at 10:17 PM. Reason: Added 'historically supportable'

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    Quote Originally Posted by Selfsim View Post
    The model was developed gradually from the data. That differs from searching specifically for another instance of something which already exists. The two areas are not the same by any comparison I can envisage.
    Yes. To look for life on other worlds is to search for another instance of something which is already known to exist.

    Not comparable to the way atomic physics developed? Maybe not...

    But what about the scientists who worked on the question of exo-planets, before the existence of exo-planets was definitely established?

    Weren't they "searching specifically for another instance" of a sun with planets?

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    Quote Originally Posted by Colin Robinson View Post
    Yes. To look for life on other worlds is to search for another instance of something which is already known to exist.

    Not comparable to the way atomic physics developed? Maybe not...

    But what about the scientists who worked on the question of exo-planets, before the existence of exo-planets was definitely established?

    Weren't they "searching specifically for another instance" of a sun with planets?
    Well, if those scientists were unsuccessful .. (and they were) … then they were clearly barking up the wrong tree ... right up until the first exo-planet discovery !

    As it turns out, in fact, the first exo-planet was discovered purely by chance, and was a direct result of observing a millisecond Pulsar in 1992, (PSR 1257+12), with the intention of making precise timing measurements of the pulses ! The Pulsar was found to not even be associated with a companion stellar object !

    In other words, the act of exploration, (as opposed to a deliberate, preconceived search for a 'sun with planets'), was the cause of the discovery. Ie: random chance, (pure luck), combined with the deliberate act of exploration within practical capabilities, in this case, resulted in a totally unexpected exo-planet discovery !

    Centuries of dreaming of finding a 'sun with planets' was just that … a dream … nothing more.

    I assert that in cases like this, acting upon a dream, with the belief in mind that the capability will materialise because of that belief, is just plain naivity. The bulk of the effort in creating the enabling technologies leading to subsequent exo-planet discoveries, eventually came about for a whole pile of other unrelated reasons.

    What came after the first discovery might be a better example of your point (?) But I'd say after the first discovery, the quest became to find how many are out there. After the first few discoveries, the 'how many' question, (for me), rapidly disappeared again … back into the 'noise' ...

    Regards

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    Quote Originally Posted by Selfsim View Post
    Well, if those scientists were unsuccessful .. (and they were) … then they were clearly barking up the wrong tree ... right up until the first exo-planet discovery !
    They were raising a question which they were not able to answer conclusively.

    As it turns out, in fact, the first exo-planet was discovered purely by chance, and was a direct result of observing a millisecond Pulsar in 1992, (PSR 1257+12), with the intention of making precise timing measurements of the pulses !
    Yes, and the people who timed the pulses concluded that they had found exoplanets, and the scientific community agreed.

    Could that have happened if the question of exo-planets had not previously been a topic of discussion among scientists?

    Centuries of dreaming of finding a 'sun with planets' was just that … a dream … nothing more.
    A dream that came true in an unexpected way.

    I assert that in cases like this, acting upon a dream, with the belief in mind that the capability will materialise because of that belief, is just plain naivity. The bulk of the effort in creating the enabling technologies leading to subsequent exo-planet discoveries, eventually came about for a whole pile of other unrelated reasons.
    I'd agree that the capabilities don't develop only because scientists formulate questions whose answers they yearn to find.

    There usually are "unrelated reasons" for scientific advances, like rocket technology being developed for military purposes, and afterwards being used to study the solar system and to launch space telescopes...

    So, to raise a scientific question insistently is not a sufficient condition for an answer to arrive... Then why do scientists raise questions which cannot be immediately answered?

    Raising a question cannot guarantee an answer. But without the question, would the answer ever come?

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    QM has its, ahem, less than scientific "theories," such as the many-universes hypothesis. Currently, the evidence supporting string theory is not much better than that for non-terrestrial life.

    The questions that astrobiology purports to investigate -- "how did life originate?" and "could it originate someplace else?" -- are both sensible, scientifically acceptable questions, albeit ones which cannot be currently answered. In this regard, they are really no different than questions like "what happens inside a black hole?"
    Information about American English usage here and here. Floating point issues? Please read this before posting.

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    Quote Originally Posted by Colin Robinson View Post
    But what about the scientists who worked on the question of exo-planets, before the existence of exo-planets was definitely established?
    This is a very good question. Answering it could shed some light on the scientific process. I would add some further questions:
    1) Did these scientists work on theoretical aspects of exoplanet detection methods which later contributed to actual exo-planet detection?
    2) Did they actually attempt to detect exoplanets?
    3) If the answers are yes to 1) and 2) then we should ask why they failed to detect exo-planets. Were there perhaps technological limitations at the time?

    I think the problems with exo-planets and exo-life detection are mainly technological, i.e. to develop the technological means to detect them. The scientific issues are to learn more about these things, but the question of whether these things exist or not is really not the big question. It is not as if the scientists were surprised then by the discovery of exo-planets, as in: "Wow!, I didn't know that's possible. So exo-planets do exist after all? Gee! That's really paradigm changing!". The same applies to exo-life. All our efforts should go into developing the scientific theories, methods and technologies that would increase our chances of detecting exo-life, instead of getting stuck on the question of whether it exists or not.
    Last edited by Paul Wally; 2012-May-06 at 06:20 PM. Reason: "detection"

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    Quote Originally Posted by Colin Robinson View Post
    So, to raise a scientific question insistently is not a sufficient condition for an answer to arrive... Then why do scientists raise questions which cannot be immediately answered?
    errr … because that's what humans do .. and why the checks and balances in the scientific process, were developed in so far as to redirect such thoughts and efforts, back into the real universe, and out of delusional thinking.

    Quote Originally Posted by Colin Robinson
    Raising a question cannot guarantee an answer. But without the question, would the answer ever come?
    Who is challenging the raising of scientific queries ?
    Certainly not me ! As I stated previously:
    Quote Originally Posted by Selfsim
    the issue lies in over-emphasing the reality of hypotheses with the view to directly acting upon them. Prioritising a hypothesis based venture and depleting resources away from non-hypotheses based science projects is a growing issue thesedays, ..
    Dedicating major resources to pursuing an inference whose assumptions are taken as reality, is a flaw in rationale. Science has a long history of trying to dispel the dogma established by using this approach.

    When it can be demonstrated that other competing projects can return results, at least capable of constraining the possibility-space, (ie: actively demonstrate correlations between measured HZs and the presence/absence of exo-life), these project should take priority.

    Regards

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    Quote Originally Posted by Paul Wally View Post
    I think the problems with exo-planets and exo-life detection are mainly technological, i.e. to develop the technological means to detect them. The scientific issues are to learn more about these things, but the question of whether these things exist or not is really not the big question. It is not as if the scientists were surprised then by the discovery of exo-planets, as in: "Wow!, I didn't know that's possible. So exo-planets do exist after all? Gee! That's really paradigm changing!". The same applies to exo-life. All our efforts should go into developing the scientific theories, methods and technologies that would increase our chances of detecting exo-life, instead of getting stuck on the question of whether it exists or not.
    So why execute projects which we know are incapable (in practice) of answering the question (ie: unfeasible in practice).. when we have others which are capable (in practice) of answering the question (ie: feasible) ?

    Clearly, there is a case to be accounted for, as far as the existence of exo-life, (even if your view is, that there is none) .. for example, why has NASA gone out of its way to declare that the MSL/Curiosity is mission is specifically not for the sole purpose of detecting life ? Why does Claudio Maccone encourage political 'trickery' in the SETI camp by advising SETI folk to leverage the successful Cosmology stream, in order to move exo-life investigation forwards ?

    Quote Originally Posted by Paul Wally
    Whether these things exist or not is really not the big question …
    {snip} …
    All our efforts should go into developing the scientific theories, methods and technologies that would increase our chances of detecting exo-life, instead of getting stuck on the question of whether it exists or not.
    If this is the case, why does Chris McKay openly state that: "the generalisation of the phenomenon of life is 'hard' because we only have one instance of life to draw from, and that this is a case where the science will only advance by going out and looking, and we really need to be driven by the data" (~9:56 min mark) … and that: "we can't even replicate our own life … we are far from being able to synthesise our own life in the laboratory … we are way, way too early in our understanding of life to rule anything out, or anything in" .. "we're lost" (~11:47mins).

    If all this is the case, then exactly why is the existence or not, of 'these things' (ie: exo-life), not a big question ? (It certainly seems that McKay thinks it is). If its as hard as he says, then why not do as he says … ie: go out and look for it, by generating the data which leads to answers ... as opposed to making attempts at constructing a 'hard'-to-construct theory ?

    Technology 'Problems':
    Why does Marc Kaufman also argue the same point, that the technology is absent for detecting exo-life and yet, it is widely known that the remote exo-gas sensing technology (over lyr distances), already exists ? It would seem that its practical application over light-year distances, in terms of expecting to be able to draw conclusions from the results, is where the problems set in, and these 'problems' arise specifically because of a lack of past instance reference data to support any correlations which might be observed.. ie: not technology limitations at all .. just plain old missing data !

    Why is it reported that the target exo-species detection technologies have already been tested, and demonstrated to be effective in detecting life ?

    Are LR, racemic and chirality tests, also unsupported in technology ?

    Regards

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    Quote Originally Posted by Selfsim View Post
    So why execute projects which we know are incapable (in practice) of answering the question (ie: unfeasible in practice).. when we have others which are capable (in practice) of answering the question (ie: feasible) ?
    Which projects are incapable of answering what question? I'm sure there are some projects (yet to be developed) capable of answering some questions, but I don't think you can predict what projects will be developed, and how technology would develop and what we may possibly discover. It's seems more that you want to block the process even before it has started.

    Clearly, there is a case to be accounted for, as far as the existence of exo-life, (even if your view is, that there is none) .. for example, why has NASA gone out of its way to declare that the MSL/Curiosity is mission is specifically not for the sole purpose of detecting life ?
    Is that so? Perhaps it's for the simple logical reason that if there is no life to detect the mission will at least be useful for other purposes also.

    Why does Claudio Maccone encourage political 'trickery' in the SETI camp by advising SETI folk to leverage the successful Cosmology stream, in order to move exo-life investigation forwards ?
    Now why do you have to drag politics and other people's opinions into a discussion of purely logical and physical possibilities?


    If all this is the case, then exactly why is the existence or not, of 'these things' (ie: exo-life), not a big question ? (It certainly seems that McKay thinks it is). If its as hard as he says, then why not do as he says … ie: go out and look for it, by generating the data which leads to answers ... as opposed to making attempts at constructing a 'hard'-to-construct theory ?
    There's nothing wrong with attempting to construct any theory. Now it seems not only do you not want empirical research relating to extra-solar life, you also don't want theoretical progress.

  23. #113
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    Quote Originally Posted by Paul Wally View Post
    for example, why has NASA gone out of its way to declare that the MSL/Curiosity is mission is specifically not for the sole purpose of detecting life ?
    Is that so? Perhaps it's for the simple logical reason that if there is no life to detect the mission will at least be useful for other purposes also.
    There is a detailed "horse's mouth" explanation of the mission's scientific aims at MSL Science Corner: Science Goals. As explained there, they are not looking directly for organisms, but they are looking for complex organic compounds. This is something that has not been attempted since the Viking mission, except by the British mission Beagle 2 which didn't land successfully.

    An excerpt from the NASA page:

    MSL is not a life detection mission and is not designed to detect extant vital processes that would betray present-day microbial metabolism. Nor does it have the ability to image microorganisms or their fossil equivalents. MSL does have, however, the capability to detect complex organic molecules in rocks and soils. If present, these might be of biological origin, but could also reflect the influx of carbonaceous meteorites… MSL will also be able to evaluate the concentration and isotopic composition of potentially biogenic atmospheric gases such as methane, which has recently been detected in the modern atmosphere.

  24. #114
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    Quote Originally Posted by Paul Wally View Post
    Which projects are incapable of answering what question? I'm sure there are some projects (yet to be developed) capable of answering some questions, but I don't think you can predict what projects will be developed, and how technology would develop and what we may possibly discover. It's seems more that you want to block the process even before it has started.
    See the two new threads I started:

    i) ESA EChO Exo-Gas Mission - This thread describes a proposal for an orbital exo-gas detection telescope. I assert that if this project were to go ahead in isolation, (hypothetically), the data returned by it, would be so unconstrained, (only in as far as exo-life detection progress), any exo-life conclusions it might make, would be highly questionable. It is critically dependent on data from local exploration of other Solar System HZs and/or exo-life exploration conclusions.

    ii) Exo-Oceans Not Detectable ? - I think its fair enough to regard the paper in this thread as highlighting present limitations, (which admittedly, may well be overcome further down the track). However, it serves as a pertinent reminder about the present limitations of specular reflectometry and its inaccuracies, when it comes to detecting 'waterworlds' (still a NASA high priority Astrobiological target environment).

    Regards

  25. #115
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    Quote Originally Posted by Selfsim View Post
    See the two new threads I started:

    i) ESA EChO Exo-Gas Mission - This thread describes a proposal for an orbital exo-gas detection telescope. I assert that if this project were to go ahead in isolation, (hypothetically), the data returned by it, would be so unconstrained, (only in as far as exo-life detection progress), any exo-life conclusions it might make, would be highly questionable. It is critically dependent on data from local exploration of other Solar System HZs and/or exo-life exploration conclusions.
    It's good to hear that ESA is planning such a mission. Just to get data from exo-planet atmospheric composition would be valuable in itself. I mean, it should at least tell us whether some earth-like physical conditions are common in universe. The conclusions that can be drawn from the data, I think, depends on the broader research process which may not necessarily include a simultaneous "local exploration" mission.

    Quote Originally Posted by Selfsim View Post
    ii) Exo-Oceans Not Detectable ? - I think its fair enough to regard the paper in this thread as highlighting present limitations, (which admittedly, may well be overcome further down the track). However, it serves as a pertinent reminder about the present limitations of specular reflectometry and its inaccuracies, when it comes to detecting 'waterworlds' (still a NASA high priority Astrobiological target environment).
    Sure, there are limitations. Things are certainly developing faster than I expected, people went from talking about hot Jupiter's, to Neptunes, to super Earth's, to Earth sized planets and 'waterworlds' in a very short period of time. May I ask why you put waterworld in inverted commas? You think it's nonsense?

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    Quote Originally Posted by Paul Wally View Post
    It's good to hear that ESA is planning such a mission. Just to get data from exo-planet atmospheric composition would be valuable in itself. I mean, it should at least tell us whether some earth-like physical conditions are common in universe.
    How does making such a finding, necessarily result in the conclusion of "common in the universe" ?
    Is drawing conclusions about frequency distributions statistically valid for a parent population of the size of the observable universe ? How so ?

    Quote Originally Posted by Paul Wally
    The conclusions that can be drawn from the data, I think, depends on the broader research process which may not necessarily include a simultaneous "local exploration" mission.
    Local exploration and localised bio-testing is the only means by which verification can be practically achieved. (Apart from direct ET contact, caused by a random chance discovery).

    Quote Originally Posted by Paul Wally
    Sure, there are limitations. Things are certainly developing faster than I expected, people went from talking about hot Jupiter's, to Neptunes, to super Earth's, to Earth sized planets and 'waterworlds' in a very short period of time. May I ask why you put waterworld in inverted commas? You think it's nonsense?
    No .. in this case, my thoughts don't effect the physical reality.
    For me, the term 'waterworld' anthropomorphises the reality … which would be a lump of rock and water.
    The term 'world' includes countries, people, societies, institutions and other natural features. Until there is evidence of such things, the application of such a term is premature, and unjustifiably prescriptive.

    (Nonetheless, others here seem to take some solace in the use of the term).

    Regards

  27. #117
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    Quote Originally Posted by Selfsim View Post
    How does making such a finding, necessarily result in the conclusion of "common in the universe" ?
    Is drawing conclusions about frequency distributions statistically valid for a parent population of the size of the observable universe ? How so ?
    It surely doesn't look as if we are located in a particularly special corner of the universe. If you have evidence that general conditions where the local group of stars are located are especially different from elsewhere in the galaxy and that our galaxy is especially different from the other galaxies in the universe then please present it. My main point, however, is that the data will have scientific value even if we cannot conclude the existence of life from it. You seem to think that if we cannot conclude the existence of exo-life from such a mission we shouldn't even bother doing it in the first place. Any information is better than nothing.

    No .. in this case, my thoughts don't effect the physical reality.
    For me, the term 'waterworld' anthropomorphises the reality … which would be a lump of rock and water.
    The term 'world' includes countries, people, societies, institutions and other natural features. Until there is evidence of such things, the application of such a term is premature, and unjustifiably prescriptive.

    (Nonetheless, others here seem to take some solace in the use of the term).
    I don't think the intended meaning of the term "waterworld" is that it must be populated, but simply that it is a planet covered with water. Do you have possible reasons why planets covered with water couldn't exist or why they would be unlikely?

  28. #118
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    Quote Originally Posted by Selfsim
    How does making such a finding, necessarily result in the conclusion of "common in the universe" ?

    Quote Originally Posted by Paul Wally View Post
    It surely doesn't look as if we are located in a particularly special corner of the universe. If you have evidence that general conditions where the local group of stars are located are especially different from elsewhere in the galaxy and that our galaxy is especially different from the other galaxies in the universe then please present it.
    The Cosmological Principle can be formally stated (from Wiki):
    'Viewed on a sufficiently large scale, the properties of the Universe are the same for all observers.' This amounts to the strongly philosophical statement that the part of the Universe which we can see is a fair sample, and that the same physical laws apply throughout.
    So, there is nothing in that, which states that the properties of two particular planets, when viewed at the scale level of Earth's oceans, which formed under the same Laws of Physics/Chemistry, will exhibit the same physical characteristics at that scale.
    As a matter of fact, (as a sample), of the ~180 (??) moons/planets/dwarf planet rocky bodies in our Solar System, to the best of my knowledge, no two are identical at the scale of the oceans of Earth, nor are there any such bodies having liquid oceans which resemble Earth's (chemically, volumes, etc). And such a sample also doesn't rule out oceans of water on exo-'waterworlds' .. Inferences drawn either way, on these bases at these scales, are meaningless.

    All this happens without the need for invoking anything 'special' about our location in the galaxy (or universe).

    If it was all so formulaic, then we could predict the appearance of liquid oceans .. and we can't. Thus, for the same reasons, we cannot predict the distribution, and thence, the 'likelihood', of exo-'waterworlds'.

    Quote Originally Posted by Paul Wally
    My main point, however, is that the data will have scientific value even if we cannot conclude the existence of life from it. You seem to think that if we cannot conclude the existence of exo-life from such a mission we shouldn't even bother doing it in the first place. Any information is better than nothing.
    (Re: the underlined bit): That is not what I think .. I have repeated my views on this so many times, all I can conclude is that there is some kind of impediment preventing my message from getting through .. I expressed candidly, where I was coming from in post #104.

    Quote Originally Posted by Selfsim
    The term 'world' includes countries, people, societies, institutions and other natural features.
    Quote Originally Posted by Paul Wally
    I don't think the intended meaning of the term "waterworld" is that it must be populated, but simply that it is a planet covered with water.
    … The definition came from the Merriam-Webster dictionary.

    Quote Originally Posted by Paul Wally
    Do you have possible reasons why planets covered with water couldn't exist or why they would be unlikely?
    Why are you asking me ? The answer to such a question is not relevant from where I stand.

    Regards

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    The argument for waterworlds depends on simulations of planetary formation, which seem to predict that a high proportion of terrestrial planets will have deep, or very deep, coverings of water. I note that the wiki page calls them 'ocean planets'
    http://en.wikipedia.org/wiki/Ocean_planet
    this was the label given to them by Kuchner and Leger in 2003, and may have been chosen deliberately to avoid the implication that such planets might be inhabited 'worlds'.

    In fact it might be difficult or impossible for life to emerge on a deep ocean planet, as there would be no rockpools on the surface where organic chemicals might collect and become concentrated enough to react and interact. A deep ocean planet would be a very dilute environment, or so it seems to me (the same would probably be true of a gas giant).

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    Merriam-Webster actually offers a list of different senses of "world", one of which is "14. a celestial body (as a planet)".

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