I think it fairly safe to say that those you think were claiming a non existence position where actually only rejecting your evidence and assumptions.
Its fine to have assumptions, but if you use them to justify a position then you should expect to have them challenged.
I lurkex around these boards for a while before joining. I was very active over on Wikipedia before joining here, and most of my time was consumed by making editors find reputable sources for what they were putting in articles. I pay a lot of attention to detail and so I guess I was just taken aback when I interpreted replies to my posts to mean that I was being unreasonable in my beliefs because I thought I was being explicit in saying that my beliefs are not assumptions. I guess it's pretty silly to start all of this over the definition of a word.
And I really only wanted to know the truth value of "not assuming aliens do not exist". Throwing what I believe into the mix probably muddied the waters, but that was not my intention. I just wanted to make clear what I believe because I think that is important to know for someone who is evaluating your statements.
well, if you came to these boards and claimed it as knowledge that ET existed, you'd get carried away in a straight jacket.
The debates here are essentially between those with your position, who consider they have grounds for a reasonable belief - and those who do not consider your evidence leading you to that belief as legitimate.
I am entirely neutral on the question of life - that means that I neither think it likely or unlikely - its just unknown. I think thats where most you thought denied the possibility of ET life also sit.
I may have missed this point being raised earlier, if so I apologise for skimming..!
But it seems to me that the claim we have an abundance of life here on earth is VERY misleading. By definition (assuming you accept evolution), 'abundance' is what inevitably happens once you have a SINGLE outbreak of life. And as far as I am aware there is no evidence of anything but one single outbreak of life, somewhere on this planet, at some particular time, under very precise (and at this stage, unknown) conditions. In all the time before or since, no other life has sprung into existence. In all of our (perhaps crude and simplistic) experiments, not once have we managed to duplicate those conditions. In other words, rather than it being very likely that life will spring up given the right earth-like conditions, I would argue exactly the reverse...
So based on what I see (or rather DON'T see) here on Terra, I think the chance of life existing elsewhere is pretty much vanishingly small. While I don't dispute there may be some of it elsewhere, given the tyranny of distance and all the other factors of timing, self- and cosmological- destruction, the chance of it becoming intelligent/sentient let alone technological, let alone interested in 'reaching out'... I'll happily accept that we are, for all intents and purposes, currently - and likely for the duration of our race - quite alone.
And btw, that doesn't depress me at all - I find plenty of other stuff easily interesting enough to keep me occupied..
There's a difference between making assumptions and making suppositions. Look, I just supposed X and then I supposed not(X) (no problem), but it would be irrational to assume both X and not(X).
For me, science operates at the level of supposition (not assumption), and that's where all the interesting (original) work is going on. I think it's far more interesting to have a rational discussion around different suppositions around alien life, than to have these dead-end discussions about who assumed what, and what can be assumed, and what can be said and what cannot be said. Sometimes these type of dead-end discussions even lead to restrictions on what can be thought and what cannot be thought, and this I find quite strange, because why must lack of evidence for something prevent us from thinking about the different logical possibilities?
b) Initial conditions: There is theoretical evidence that the observable universe started out chaotically. Randomness and order would seem at home in the aftermath .. and it is !
c) Primummobile: 'Mathematically unlikely: Could you please demonstrate for us, the mathematics behind such a statement ? I keep seeing 'mathematics' being used to make a point, and yet there is nothing from mathematics I know of, which would suggest that such a statement is anything more than pure arm-waving and a hijack of mathematics.
1. I dislike using the term 'special' .. something unique, doesn't have to be 'special'. That being said, I only used the term as a quote of what was said.
I would argue that we can't say very much about that based on current laboratory experiments. These laboratory experiments are extremely small scale compared to the planet over geological periods. Now, if you were conducting experiments with something like the volume of the Pacific Ocean, and you couldn't get results after a few hundred million years, then you might have a significant argument.In all of our (perhaps crude and simplistic) experiments, not once have we managed to duplicate those conditions. In other words, rather than it being very likely that life will spring up given the right earth-like conditions, I would argue exactly the reverse...
I say there is an invisible elf in my backyard. How do you prove that I am wrong?
The Leif Ericson Cruiser
Was it a sudden, perhaps fortuitous, emergence of a replicating molecule out of a random soup of organic chemicals?
Or did relatively simple catalytic cycles, favored by the principles of thermodynamics, gradually become more efficient and more complex -- cycles along the lines of the reductive Krebs process, where carboxylic acids are formed out of an energy-rich mixture of hydrogen and carbon dioxide?
If we think of it as a single event, it may seem very significant that such an event happened only once.
If we think of it a process, I'm not sure whether you would expect it to happen a second time on a planet where it has already happened -- a planet where the energy from those energy-rich chemical mixtures already has channels to flow thru.
Here are links to two articles in which abiogenesis is understood more as a process than a single event:
Christian de Duve The Beginnings of Life on Earth
James Trefil, Harold Morowitz, Eric Smith The Origin of Life
It's an important part of science to look at suppositions (not yet established as facts), and ask: If this were true, what would follow?
I'm reminded of the distinction which Karl Popper made between a "bucket" theory of knowledge and a "searchlight" theory. Whether science is like lowering a bucket into water, or more is it like aiming a searchlight? In "the searchlight" model, you have to think about where and how the searchlight is to be directed -- it isn't just a matter of letting data pour in, like water into a bucket...
(Similarly, the lack of data cannot in itself, be considered as a valid basis for formulation of the premise that exo-life doesn't exist either, as this leads to the logical fallacy of 'argumentum ad ignorantium').
I said I read the thread in question - I must have missed the bit where somebody said that. Can you provide the quotation?
Obviously, I meant the quotation that supported your claim that some were being too minimalist.
You then gave me a load of quotations, none of which support your claim that some were being too minimalist, none of which stated or implied "extraterrestrial life does not exist because we have seen no evidence of it." So perhaps you can withdraw the claim now.
Due to the paucity of data, one has to go wherever the data leads. And the data comes from exploration of the real-universe.
What's more, it is just as likely to be completely unanticipated, as it is expected from purely philosophically motivated speculation.
Our best attempts at directed searches, in the light of having no data-based premises, are basically akin to searching in near infinite space, in darkness, for something we know we can only just barely detect in our local neighbourhood, in full light, right under our noses !
With such little understanding, focussing too heavily on logical reasoning as a basis for prioritising the search space, is nothing more than being led by philosophy, metaphysics, politics and delusion.
Where is the scientific importance in that ?
Here's one that's not speculative: The existence of life on Earth, does not imply life exists elsewhere.
Earth may not be unique at the scales of, and in the attributes you mention ... and that implies nothing about life.
I have to disagree.Suppositions are superfluous.
I find it tragic that every discussion gets derailed by this discussion. The factions who want to argue about whether aliens exist are destroying the possibility of fresh discussion. How can we ever philosophise about the possible nature of otherworldly beings when the same nay sayers keep popping their heads up and shouting "HOGWASH!"
We get it. Ok. A minority of you simply can't get past this stumbling block. You would rather raise this same tired debate over and over rather than let a discussion unfold based on an assumption.
We once thought our individual nations were the centre of the world and all of creation. Clearly many of us still do.
If ever there was a thread to hammer this out .. its this one !
Your desire to "philosophise about the possible nature of otherworldly beings" would be the "derail" ... sorry to leave you in a 'tragic' state ... and all at your own calliing, I might add !
Here on BAUT (as it was) we've had all manner of speculative discussion about possible extraterrestrial life. There was even one about whether other civilisations would listen to music. And whereas one or two people did indeed fail to "get it" (i.e. that the discussion was purely speculative) they did not derail the thread.
This thread started about logic and assumptions. In fiction we can examine weird starting assumptions using logic and imagination. Usually fiction writers who then claim the details are factual are disapproved.
It is important to separate what we regard as evidence from extrapolation and imagination when using the mantle of logic to arrive at conclusions.
If we are separated by too many light years, the mathematical possibility of life on distant planets surely remains a subject for fiction, we cannot expect to find evidence.
When we study the universe, we make hypotheses based on known physics. Sometimes we've found things that didn't fit known physics, but a lot of it has. It has certainly been something to build on.
Similarly, if we're going to look for exolife (as I think everyone here agrees with the possibility of exolife and that it is a possibility that should be investigated, correct?) it would seem reasonable to make hypotheses based on known life. That doesn't stop anyone from considering other possibilities, but it would be a reasonable place to start.
I say there is an invisible elf in my backyard. How do you prove that I am wrong?
The Leif Ericson Cruiser
But that is sorta my point - either:We wouldn't know about other abiogenesis events unless they happened to have current and distinct descendents, or if there was something very distinct left in the fossil record. It's possible there have been multiple abiogenesis events on Earth.
1. There is/was one very precise, extremely unlikely set of conditions and chemicals from which life can appear - which is the one I'm betting on...
2. There is a range of conditions and chemicals, or if they are precise, those conditions were (even briefly) widespread - in which case we *would* very likely see distinct descendants (in a regional sense) / differing biochemistry / fossil records
Do we? AFAIK, we don't, and I think we probably should. I'll happily admit I'm not widely read on this aspect of abiogenesis, but I've never seen any references to multiple 'beginnings'. Perhaps the books that were cited give some clues, but it would be nice if this aspect got a bit of coverage here..
I'm not sure I agree. If we had no idea of what we are after, then yes, but we DO know what we are after! We have examples of the primitive starting points of life all around us - they are chemically analysable, we understand the basic processes, the chemical structures... It's a pretty good example of reverse engineering where you not only have the blueprints, you also have as many samples as you need to dissect / analyse..I would argue that we can't say very much about that based on current laboratory experiments. These laboratory experiments are extremely small scale compared to the planet over geological periods. Now, if you were conducting experiments with something like the volume of the Pacific Ocean, and you couldn't get results after a few hundred million years, then you might have a significant argument.
Of course we can't quantify it meaningfully in mathematical terms, but I think it's fair to say it is really, really difficult to get life started. Maybe even a few more reallys...
So I stand by my point - saying that life is 'abundant' on Earth is misleading, in this context.
Sure, but don't forget the testability part of a proper hypothesis. In isolation, I don't challenge the 'reasonableness' of the general idea of looking for Earth-life, if one chooses to pursue the search for exo-life ... after all, there is no other choice once one embarks on such a quest. Carbon based biological life tests have to be conducted locally (or via return sample ... oh, SETI signals or ET poking faces at a robotic camera might suffice as well). This limits the practicality of the testing. Such tests cannot be applied over light year distances. This means that the hypothesis is severely constrained by practical testing limitations which ultimately limits the ability to gather the data, and form conclusions. No amount of 'reasonableness' (or logical reasoning) will overcome this practicality imposed limitation. Also, we simply don't have any data to make the firm connection between what we can measure these scales, and the presence/absence of life (whist excluding other unknown non-biological processes).Originally Posted by Van Rijn
Using Physical theories to make exo-life hypotheses: the raw fundamental laws of physics dominate at astronomical scales, (and on astronomical objects), but in complex systems, their complex interactions can have entirely unexpected and unpredictable results. In the absence of any data on exo-life, it is also reasonable to say that deterministic physical theories can only be used to infer where exo-life may exist elsewhere (at best). Using Earth-life as a substitute for Physical Law as you have suggested, comes with all the limitations outlined above.