Universal Perfection

I think you're acting like life on Earth is all the life that exists. Sure, it's all the life that we know exists, but we don't know that it doesn't exist anywhere else, and we don't know how it exists, and the laws of physics suggest that it could exist based on other chemistries. That's what she's pointing out to you - that simply because all the life we know of is based on a certain chemistry - which by the way should be obvious, given that all life forms are decended from the same organism - that doesn't suggest a hidden law of physics that could prevent life from being based on another chemistry. You're proposing a hidden law. We're saying that there's no evidence for one.

I'm sorry you'll have to point out where you've talked about life on other planets. As far as I've read you've talked about all the life we can observe, and as far as I know, all that life is on Earth. Can you point out where you've said anything about life on other planets? Don't have 'em. We're just speculating, after all. What's life? Reiterating chemistry. Can molecules based on silicon reiterate? Sure. Seriously? You're seriously asking this? Like, you seriously don't know?I would have thought it would be obvious. The reason we don't see life based on those chemisties on Earth is because oxygen-carbon chemistry won. There's no way life based on those chemistries could gain a foothold on an Earth filled with carbon life. The carbon-oxygen biome is not compatible with that kind of life.Basically you can't mix chemistries. If we find life based on different chemistry, it'll be the only chemistry on that planet.

Ok, it begins to get a little clearer -

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PS: I am not claiming "I am right and you are wrong": we don't know which position is actually true.

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- you're just setting up a false dichotomy. Our position is that life could exist based on other chemistries. Your position is that all the life we know of is based on carbon and oxygen chemistry.I fail to see why these positions can't both be correct. The problem is that if they're both true, it kind of eliminates the idea of "fine-tuning", because you can't know about what could exist in another universe. If all possibilities lead to some form of life, in any imaginable sense, then you can hardly say we're "fine-tuned" for life, can you?It sounds to me like we're both doing a fair bit of speculation. The difference is Rei's speculation (not trying to eliminate myself from the discussion here, but rather to avoid taking credit for Rei's work in this discussion) could be confirmed by potential observations in other areas of the universe. Your speculation of fine-tuning, however, can never be confirmed or denied unless we can peek into other universes.

Duh. You said it yourself, in a post to Rei. (Possibly in another thread, now that I think about it.) You mentioned that silicon-hydrogen molecules would be disasterous in the presence of oxygen.Carbon biomes release oxygen, as we observe. The oxygen, therefore, rules out the possibility of silicon based life. Carbon-based life isn't compatible with silicon-based life, ergo we only see one or the other.Silicon based life could exist, it just couldn't exist where carbon life already had a foothold. I'm not enough of a biochemist to know if even a well-established silicon biome could survive carbon-based life. I doubt it, really.

Yes, that's the true dichotomy. The problem is, the fact that we observe that all the life on one little planet in a corner of the big, big universe has only one kind of life is not evidence for number 1. Neither, of course, is it evidence for number two. There's simply insufficient evidence to know which is correct. In the meantime it would seem reasonable to go with the assumption that doesn't assume an undiscovered law of chemistry; number 2. But such a position can't even be supported. When you say that "life is restricted to LAWKI", you're using a circular definition of life. You're saying that life as we know it can only be life as we know it. Of course that's true. There's no way we could know about life that isn't life as we know it, by definition.If you want to play with circular definitions, that's fine. I like to play with Ockham's Razor. Since there's no physical law that prevents life as we don't know it, I'll assume that it could exist. To assume otherwise would be to assume an unknown physical law that would prevent it.

It wasn't the one you were using when I jumped in. It certainly wasn't the dichotomy Rei was a part of. Nonetheless I'll let you move whatever goalposts you like; the arguments are largely the same. Then why do you insist on using it to do just that? Why is it when we say "life could exist in other forms" you say "you're wrong; the fact that we don't observe such life proves it."If it's not enough to prove one way or the other then it's irrelevant to the discussion, as we're talking about what could be, not what is. And as you say, it supports neither conclusion. As a result the empirical evidence is irrelevant to this discussion. I'm sure you know that isn't true. Yet, both positions are unconfirmable. Therefore neither position can be used in relevance to a discussion of fine-tuning. You don't know that the universe is fine-tuned, because you don't know the ratio between outcomes that could support life, and outcomes that couldn't, because you don't exhaustively know which outcomes could support life besides ours. You don't even know which outcomes couldn't support life.Since you've cut the legs out from your own position by admitting that it's not knowable at this time which outcomes could support life and which could not, how can you make a fine-tuning argument? After all, our position is that you can't know that the universe is in any way fine-tuned. The undecidability of your dichotomy is evidence for our view and a damning counterstroke against yours.

We're starting to lose sight again of what we're talking about. I'll explain again what I see the argument as; hpefully that will prompt some substantial rebuttals from you.I see this as you arguing that you know the universe is fine-tuned for life because the physical parameters that allow for LAWKI are narrow and apparently arbitrary. Right? So the "odds" of them just "happening" to be the way they are are low indeed. Right?And we're saying that there's no way you can know that to be true, which you apparently agree with - there's just no telling - no evidence - about what physical parameters could support LAWDKI - life as we don't know it - because, by definition, we don't know that life. Ergo suggestions of "fine-tuning" imply considerably greater knowledge than you admit it's possible to have.So, where's your argument? If you've agreed with everything that supports our position and not yours, why do you insist on making a totally unsupported conclusion of "fine-tuning"?I repeat my argument - to know that the universe is "fine-tuned" for life, you would have to know exhaustively the ratio of universes that support life - not just LAWKI, which you seem to admit is not necessarily all the life that could be - compared to the universes that can't support life of any kind, not just LAWKI.You all seem pretty hung up on LAWKI, but we've established that since he have no idea of how large a subset of all possible life LAWKI is, I don't see why it's relevant in the least to the proposition that the universe is "fine-tuned" for life.

Of course I am. I'm also a guy who knows what evidence is. "As far as we know, we're the only life" isn't the same as "there's evidence that we're the only life." After all "as far as we know" consists of two planets around one star, in a corner of one galaxy, out of a universe with countless billions of both. The fact that we've only found life in one of the two places we've looked is hardly evidence that we're alone in the vast universe.

Given that DNA seems intent on fixating on any percieved slight as a pretense to avoid substantial argument, isn't it better to just kind of ignore this stuff? It's annoying, yes, but I find Joralex's use of yellow text far more objectionable. I guess I'd think about his code brackets as though they were a huge pimple on his forehead - it's shocking and distracting, sure, but evenutally you're just going to have to overlook it if you want to talk to him.

Well, discussion is, after all, the process by which we make our arguments clearer.Now, I ask again, do you have substantial rebuttals to my core arguments? Which is: how can you make an argument for fine-tuning when you admit that the question of what life could be like besides how we know it isn't even answerable at this time?My position is that no argument could be made; therefore the ambiguity about the existence of life-as-we-don't-know-it supports my position and not yours. Your position appears to be that despite this ambiguity, we can somehow know that the universe is fine-tuned for life. I simply don't see how this is so.