> Both claim that God does not exist.

This is not true.
A weak atheist is someone who doesn't believe that a god exists but does not assert no god exists.
His position is not making any claims but rejecting the claims of theists.
The court analogy would be when the judge thinks that the suspect has commited the crime but can't declare him guilty of the crime because of insufficient evidence.
The judge thinks that he is probably a murderer but doesn't assert that he is because it isn't beyond reasonable doubt...

>I distinguished the two only to show how confident they are in these positions.

Agnostic atheism can mean different things depending on how the word agnostic is used.
As it is used in philosophy, it doesn't even make sense to say agnostic atheist. You can't be both.
If however atheism is used as non-belief then saying weak or maybe even agnostic atheism makes it clear that the claim is not made.
Without this you don't know whether one also asserts/believes that no god exists or if they are just unconvinced that he does.
With weak/agnostic you now know that they don't make the claim.

>If the "weak atheist" is not making a claim about God's existence, but is suspending judgment, they are not an atheist but an agnostic.

I agree but then you are using the definitions in philosophy in which case you are correct and weak atheism will have to mean something different like the confidence.

>So you claim. Most experts, including atheist ones, would disagree, assuming "serious" here is a judgment on the respectability of a position as something worth "seriously" considering.

I think you may have understood something different than what I mean.
Serious evidence means something that changes things a bit.
Anecdotal evidence do not change things much.
It's like, I want to say that there is no evidence at all but then there is anecdotal evidence and it does count as some form of evidence I guess but it is not evidence that matters much.
There's evidence that aliens visited and abducted human beings.
But it's trash evidence.
I was reffering to the evidence, the position may be philosophically at the very least worth considering.

>Not at all. I was addressing when the absence of evidence for a thing may count as evidence for its absence. This does not say that is the only way or time we may suppose the non-existence of a thing.

Well then you are saying that it is either confirmed or debunked as you are not saying that it is neither confirmed nor debunked.
So which is it?
When there is absense of evidence of a thing does this mean that the thing exists or does it mean that it does not exist?

This seems to go against god... Absence of evidence is definitely what we observe and the only way this would make sense is if god doesn't exist or is beyond detection.
Do you think that if such a god as the one that you believe in exists we wouldn't expect to find strong evidence of its existence?

>Is there?

Yes. Planet earth hosts inteligent life so there's a chance that is almost certainly not negligible for the universe to have created life on one planet so there's a non negligible chance that life exists elsewhere.
At least based on currect evidence, we definitely need to learn more about how life formed etc and make better assesments of how likely it is.
Right now we can't even come up with a reliable estimate that has narrow bars.
But it is likely.
Let's think of it this way:
We have a number generator and is spawns a gazilion different numbers
From -gazillion to +gazillion
with gazillion I just mean huge number.
The number 0 is planet with intelligent life.
One planet has happened to be 0.
So even though 0 is very rare compared to all other numbers
The generator has also produced a gazzilion numbers.
We know that one planet is 0 so the chance that 0 occurs is probably not very small. If the chance was very small that 0 would occur after all those gazzilion numbers generated then we wouldn't be here to talk about it.(Probably, maybe we were lucky).
So we were probably not lucky and it was normal.
So if we expect that the probability that the generator produces 0 is not small(it happened, so lets say that the chance is 1 in gazillion since that's how many numbers the generator produced) then there's a good chance that there are other planets with intelligent life.
Now, this may not be good evidence, I don't know I may be wrong.
In any case, the absence of observing aliens is not surpising since we can't really see what happens in most other planets.
I am not saying that the case that aliens exist can be made.
If that was the case then we wouldn't be ignorant about their existence.
I just find it likely.
I find it more likely that intelligent alliens exist than their non existence.
But it is likely that I am wrong and alliens aren't more likely to exist than not. Or maybe they are actually more likely not to exist based on what we know.
It's certainly possible that they exist because earth has proven that life, even intelligent life, can exist in this universe.
It's not a claim that is outside of our reality.

>This must be evidence of a very different sort then, because to my knowledge we have no found life anywhere else.

My point is that maybe we don't need to.
But ok, when I say likely, I don't express as much confidence as you may has understood. We still have insufficient evidence.
It could be 50/50. I could call even that likely.

>We must then be merely supposing that life exists then, without any direct evidence, but instead by implication (e.g. given the fact that life developed on earth, and the size of the universe).

Exactly. We could be wrong but we are likely to be correct.
Many things have been theorised/found/implicated to exist with good reasons(the math led us there) and were subsequently discovered.
Black holes is such an example. They even looked out of reality and were thought not to be real at first even though the math led there.
However, alliens don't seem to be out of reality at all.
We know of ways this could happen and that if the conditions are "right" it will happen and it would have so rare as to expect one or less times of this occuring in the entire universe.
But I mean if one expects it to happen one times after a million tries, if he lives in such one of a kind lucky shot does this not mean that in the rest 999,999 times it is still pretty much expected that another planet will have life in it? each individual planet may have 1/1,000,000 chance of having life but 999,999 make it likely that there is another one.

>So previously I established that it is sometimes rational to merely suspend judgment about a topic when you have insufficient information, rather than assert its contrary.

I agree. Many people identifying as atheists may feel like this.
In your book they are agnostics.

>I think you agree here, although you seem to switch back and forth a bit.

I agree. I don't assert that alliens exist for sure.
We need to answer the question of how likely it is for a planet to have the right conditions for life to exist. If we find this is likely given the ammount of planets that exist then it becomes more and more certain that alliens exist.
If we find that it is not so likely even with the great ammount of planets then allies are more and more certain not to exist.


>It seems like the default positions for some topics is suspending judgment, while for other topics it is denial. Perhaps, for some, the default is to assert it's truth.

How then do we tell the difference?

We use what we know to make an educated guess of how likely it is.
The flying spaghetti monster is not likely to exist based on what we know.
Alliens are. Alliens have evidence that make it likely that they exist.
It is not certain and there are other evidence which decrease the probabilitty that alliens exist but alliens may as well exist whereas the flying spaghetti monster is so removed from reality that almost certainly does not exist.

>For one thing, it's spaghetti that can fly. We have a good bit of evidence of how spaghetti works, and we're pretty sure it cannot fly. In other words, we have a defeater against the belief in flying spaghetti.

It's a special kind of spaghetti. Not the one you are used to.
In fact, is it even spaghetti? The limit is our imagination.

>Where we don't have that, this is less clear. For example, should you believe, deny, or suspend judgment to this statement "There is a particle smaller than the currently known smallest particle?"

Since I am not a physicist and don't really know I would go with suspending juedgement.
But maybe physicists know that this is unlikely as they would have detected it.
I don't know how small of a thing they can detect and there is a length that is minimum that nothing smaller can exist than that(If my understanding is correct that is...)

>and it seems to me like the right position here is not to deny its existence, but to suspend judgment.

We agree on this.
We just need examples that we have no evidence, no idea about how likely they are to be correct or not.

>There is insufficient evidence then to determine if the external world is real.

I think that the evidence points to a real word because this word doesn't seem like one that would be created by beings but by nature.
But I am fine with someone thinking otherwise in this case.
Maybe I overdo it and should be more "agnostic".
Gives you an idea of why so many atheists are what you would call agnostics.

>It seems natural to inherently trust your faculties, so in the absence of any reason to doubt them, you should not.

I mean, I feel like this could be used to validate any position almost...
Being a theist? My faculties made me one.
An atheist? The same.
I am sure not what you mean :)

>However, I think from the arguments so far I've made it clear that denial is not always the default stance.'

Atheism as defined is philosophy is not the default stance.
That would be agnosticism, the position that there is insufficient evidence to make any conclusions.
At least per default, because I think that there is evidence to be examined.