I don't think that's a proper analogy.
"i like dogs" is not a claim concerning "external" reality. It's an expression of a personal preference.
In french, we say "les gouts et les couleurs, ça ne ce discute pas".
Which roughly translates to "personal tastes, are not a subject of discussion".
Clearly "i like dogs" is of an entirely different order as saying "I believe dogs are aliens".
But in that case, me saying "I believe in God" is not a claim either. Also I could say "I like God" would not be a claim either, despite in that statement one could argue that I acknowledge the reality of God. Because its not really possible to like something which doesn't exist, even if it is just a concept, like me saying that "I like Harry potter" even though he as a physical person doesn't exist, I still acknowledge the concept or idea of him existing. So I would say that it is a claim, and I agree with you, that it is also a personal preference.
But that preference comes from my experience or exposure to God or Harry Potter, because I could just as well, say that I don't like them. But this belief could be based on me misunderstanding things about them which made me draw the wrong conclusion. So the idea is the same as I see it, because you could equally ask me why I don't like Harry Potter, and I tell you some reasons and from your perspective I got it wrong and present the real meaning or whatever, which would make the foundation of my belief wrong, or said in another way, the claim I have based my argument on is wrong.
I don't think personal preferences just come out of the blue, it is equally based on experience or an exposure to something. Unless we talk about something that we are born with obviously.
It's called the "burden of proof", but we all know that what is meant is evidence.
When a scientist expresses a belief that life exists elsewhere, people WILL ask him "why?".
To me, again, there is an equivalence here:
A: "Life exists elsewhere in the universe"
B: "what evidence supports that?"
vs
A: "I believe life exists elsewhere in the universe"
B: "why?"
==> the answer to B's question in both cases would be the same. Because it's asking about the same thing: the justification for the belief / support for the claim being believed.
Does prefixing "life exists elsewhere in the universe" with "I believe" change anything about the statement?
I don't think so. In both cases a justification would be required for it to be valid / rational.
If no such answers are forthcoming then both the statements, without and without the prefix, are without rational justification.
Which is just another way of saying that the burden of proof concerning the claim of life existing elsewhere in the universe, has not been met.
I just don't agree that you can take any claim, explicitly prefix it with "i believe" and then get to pretend that one shouldn't be challenged on it and / or that it suddenly doesn't require any form of justification anymore.
I think it's a total cop-out and just a silly excuse.
I disagree, because its sort of like ignoring the word used.
Not really sure if this explains it, but its like me saying.
"I like red cars" and then you say,
"Well you like cars"
No, I said I like
red cars, not specifically all cars. So by ignoring the word "Red" you changed the meaning of what I said, if that make sense.
Equally,
A: "Life exists elsewhere in the universe" (<- This is a truth claim. The person claim to know that life does exist out there.)
B: "what evidence supports that?" (<- Therefore asking for evidence to support that claim is rational, because why should you believe such claim to be true.)
A: "I believe life exists elsewhere in the universe" (<- Believe is simply to be convince of, or find something the most plausible explanation.)
B: "why?" (<- Its perfectly fine to ask why, but what you are interested in is the arguments that led to the set belief. And these as above, might be irrational.)
As I mentioned to
@Trailblazer or someone else earlier as well, can't remember. There is a difference between a logical claim and a non logical one. A logical claim is either true or false. Either there is life out there or there isn't. Both can't be true at the same time.
But me saying that
"Strawberry tastes better than chocolate" is still a claim, but not a logical claim, because it can't be answered with true or false. And a belief in something is not automatically a logical claim in itself. It might derive from one and I might even have misunderstood the logical claim which made me reach a irrational belief and the same goes with a none logical claim. Just to take it to the extreme, I might have gotten a strawberry wrong and thought about an apple, and when you show me a strawberry, I say that is not what I meant, clearly my original claim is wrong, due to that misunderstanding. But it doesn't change the fact, that even if that is the case, there is no way that we could conclude that "Apples/Strawberries taste better than chocolate". It is merely my believe that it is the case.
But you can easily demonstrate whether or not Life exist elsewhere in the Universe, if someone were to make that claim and wanted to be taken serious, because they could simply show it.
So the word "Believe" does matter in regards to what meaning the sentences have, just as "Red" did in the above example with the cars.