Notice the P(H|E) that is on the left side of the equation. P(H|E) is the probability that a god exists IF the universe is fine-tuned.
The term is GIVEN, not IF--and it means something slightly different, but the technical difference is critical in this case.
All probabilities are given something. That P(H) in the equation is shorthand for U.
Only in a Bayesian treatment, U is constantly changing. So we can say that it's shorthand for U
n. The whole theory behind a Bayesian treatment relies on the fact that the real world--the actual, existing world--is somewhere in your U. You don't know where exactly, but you keep modifying your U, by culling out things you know aren't so, and thus are zooming in on actuality. Each culling is a Bayesian inference. It's a degree of belief by virtue of the fact that you're constantly getting rid of things you are ruling out, and are thus winding up with higher proportions of the possibly actual worlds where some things are true and lower proportions where other things are true.
What you really have, then, is this:
P(H|E)=P(H|U
n)P(E|H)/P(E|U
n)
A Bayesian inference occurs when you cull out everything in U
n that your evidence says isn't there. That is, when you form a U
n+1 where E is true. In this new U, P(H) can be described more accurately. Bayes Theorem, in these terms, let's you do this:
U
n+1=E
|- P(H)=P(H|U
n)P(E|H)P(E|
n)
Your P(H|E) is your key to a new P(H), in a new U. Forming a Bayesian inference is forming a new U. That's a U where E is entirely true, and if you're going to keep the actual world in your U's as you modify them (the raison d'être), you had better be sure E is true.
That's why you want your E's to be something simple you can verify. Like, "this foonomia test came back positive"--you want to make damned sure that the NOT-Es you are culling out don't include the actual world. Another way to view this is that Bayesian inferences are
positive claims about the actual world.
Now, it could be that we're simply talking past each other, but I doubt it. Your Carl Sagan believes in ET intelligence analogy strongly suggests that the thing you are talking about is more than just "people who think P(H|E)>P(H)", but rather, "whether or not theists who think E is true are rational".
If it's the latter, a belief that E is true amounts to a belief that H AND E and H' AND E are the only two possibilities. If it's not the latter, what the hell does Carl Sagan's beliefs have to do with anything? And what the hell does it have to do with this entire thread--whether or not theists are rational?
Every argument assumes a premise. Stronger arguments have premises that are "merely supported by evidence" (what else would it be supported by?).
Blood on the floor is evidence supporting that there was a murder. It's weak evidence, but it is evidence. Now, in scene 2, a dead body on the floor with a knife sticking out of it is
also evidence of a murder, but is much stronger. Should I form a belief that there was a murder, "merely supported by evidence", then in both cases, you have support by evidence. "Merely supported" means that this is all you're considering--that there is support. That implies that you jump to the conclusion that there was a murder at both scenes.
Your objection seems to be using the wrong interpretation, which is better described as "supported merely by evidence", as if you have to have something else. That is not what I'm saying.
Again, you can make a valid critiques of the premise and reject the conclusion of any argument (including one based on Drake's equation).
Yes, I can. But that's not what I'm doing.
You do understand what a false dichotomy is, right?
A false dichotomy is a logical fallacy where one presents two alternatives as collectively exhaustive, when in fact there are more.
That it's a premise doesn't matter. What matters is if, in your belief system about what worlds are possible--your U--you only have two kinds of entities--such as H AND Es and H' AND Es--but where, in fact, it's quite possible that the actual world is something else--such as an H AND E', or an H' AND E'. If it can be demonstrated that the alternatives actually are the only alternatives, it's not a false dichotomy.
But just assuming, presuming, or accepting premises that the two alternatives are the only two possible alternatives, does not fit the bill. That throws you back under the bus.
And I've been qualifying this since I started.
It is not a false dichotomy to propose an argument with premises that can either be accepted or rejected.
Correct. Exactly as I have been saying alternately, in just about every response to you.
But having presented that argument, if you
accept the premises, and the premises hold that there are only two options, and you don't have good reason to suspect those are the only two,
you are committing a false dichotomy.
I've been qualifying this in nearly every post. You're telling me nothing different than what I'm saying. What I'm having issue with is that (a) you're still disagreeing with me, and (b) I'm pretty sure your entire argument relies on people actually accepting said premises. Oh, and (c), there's a way to accept the premises without committing a false dichotomy--something else I keep saying in every single post, but you keep ignoring.
Here's an idea. Rather than disagreeing with me about something I myself contend to
and am saying in every single post, why not defend the rationality of a specific set of theists who accept the premises that the universe is fine-tuned, by telling me how they aren't making a false dichotomy of presenting only that there's a god and the universe is fine tuned or there's no god and the universe is "accidentally" fine tuned...
...by telling me how they justify that those two are the only possible options? (A caveat I implicitly agree
could be there in every post, but you never actually positively try to defend people qualify for in practice).
Everything else you do here is a waste of both of our time.