The Anthropic Principal - Cosmology

If you read Dawkins statement it's really quite clear. It's an explanation in that it gives a reason why it should be the case that we happen to live on a habitable planet (which is the issue he's talking about). In calling it a truism all you are saying is that it is so obviously right that nobody should even consider another possibility.Personally I don't think that it is so obvious that it doesn't need saying, at least sometimes.

quote:

---

I could paraphrase to this: "We must be on a life sustaining planet, because we are here, on a life sustaining planet thinking about it"

---

That's hardly an accurate paraphrase. You've reduced it to a simple tautology - leaving out the point. So I have to question whether you actually understand Dawkins' statemnt correctly.Try answering this.Is it reasonably possible that things could be otherwise, that instead of being on one of the few life-friendly planets we could be elsewhere, without some reason why ?If the answer is no, then you concede that Dawkins' statement is all the explanation needed.

Since you didn't deal with my point, here it is again. "All the explanation needed" is the key. It is not a causal explanation but it presents reasons to expect things to be as hey are and it is an explanation in that sense.

quote:

---

But If we were elsewhere we would classify it as life-freindly because we would be on it. The statement is a tautology.

---

How badly wrong can you be ? We wouldn't classify it as life-friendly BECAUSE we were there. It would have to be life-friendly FOR us to be there. Unless there were some reason why we ended up there - and somehow preserved us despite the hostile environment.And that is an adequate reason for why we happen to find ourselves in a friendly (relatively speaking) environment. Edited by PaulK, : No reason given.

quote:

---

It MUST always be true. It's obviously true. And it says nothing.

---

As I said at the start it isn't so obvious that it doesn't sometimes need saying. If it didn't then why would anyone ask the question in the first place ? Why would we have people arguing that this planet is so life firendly it had to be set up for us by a god, for instance ?All logical truths are tautologies. Every valid logical argument is a tautology. If tautologies said nothing then logic would be of no use whatsoever. Thus the fact that logic is useful proves that identifying a tautology CAN tell us something.

quote:

---

Perhaps you havn't understood me. The statement is ALWAYS true.

---

Obviously you haven't understood me, or you wouldn't say that.

quote:

---

Lets assume for a moment (purely hypothetically) that God specially created the earth especially for people to live on. The statement would STILL be true. This is my whole point.

---

Mabe. However we cannot conclude that that is the case from the mere fact that we exist on a life-friendly planet. And some people need to be informed of that. Thus, they at least, are being told something by Dawkins' point.

quote:

---

Every valid argument is not a tautology. Deductive logic is a system to validly get from a set of premises to a conclusion, the truth of the conclusion still rests on the premises. The generation of tautologies is not it's primary purpose.

---

On the contrary, every logically valid argument is a tautology (at least in the simple logics typically used). I've formally studied logic in a degree-level course and was one of the basic points of the course. Indeed it is how ordinary deductive logic works - the conclusion contains nothing that is not found collectively in the premises. Thus if the premises are true the conclusion has to be - because all the rest of the argument adds nothing.I'm not sure of the point of the blog reference is as it adds nothing to this discussion (and says nothing that hasn't been said far better elsewhere - for a good introduction to logic, try this Good Math, Bad Math).Given that the author of the blog you link to seems to make the same mistakes as you in interpreting Dawkins, perhaps it is your blog and you are just trying to drive up the hit count. If this is the case I advise you to get some better content. If it is not, then I suggest you find a better source.

So long as you insist that tautologies tell us nothing the logic is definitely on-topic. Identifying tautologies does tell us something and obviously there are people who haven't identified this particular one (although it isn't quite a tautology - if there was a God it could keep us going even in an environment we "shouldn't" be able to survive in).

quote:

---

I think something that is trivially true is called a truism. A tautology is a completely true statement relying on zero assumptions. I thought this one didn't say much, but maybe for some...

---

Since Dawkins is answering an argument that some people are actually using it can't be so obvious that everybody sees it. Nobody would waste time with an argument that everybody could see to be fallacious. They must either think it good themselves or believe that others will think it to be good.