I think it depends on the belief. Some beliefs may require more justification than others.

Why do some beliefs require more justification than others? I'm interested in your theory but I'd like it in bigger pieces.

Why do some beliefs require more justification than others? I'm interested in your theory but I'd like it in bigger pieces.

a informal answer might be because that some beliefs are intuitive and others are composed...

Including what kennethamy says above, I think it also has to do with burden of proof. Different claims require different amounts, or types, of proof. From the example illustrated, if I believed the proposition, "Elvis is dead", I would be required to present more justification than if I claimed "Elvis is dead". This is because Elvis being dead is considered conventional knowledge. To believe otherwise would require me to present further evidence for my positive claim.

In other words, if someone believed "Elvis is dead", I think this would be justified based on conventional knowledge. But if someone believed "Elvis is alive", there would need to be further justification necessary.

Yes, the issue is that of initial probability. People who know all about Bayes' theorem (not me) know all about that. Given all we know, the proposition that Elvis is dead is more initially probable than is the proposition that Elvis is alive. And therefore requires less proof.

I did not consider the issue of probability. That does make sense.

I hope so. If it doesn't, a lot of mathematicians will be very angry.

Including what kennethamy says above, I think it also has to do with burden of proof. Different claims require different amounts, or types, of proof. From the example illustrated, if I believed the proposition, "Elvis is dead", I would be required to present more justification than if I claimed "Elvis is dead". This is because Elvis being dead is considered conventional knowledge. To believe otherwise would require me to present further evidence for my positive claim.

That's a weird criterion for justification, considering how wildly inaccurate conventional knowledge has been in the past.

I think that conventional belief has been pretty good. Why do you say that? For instance, conventional belief has it that the Sun will rise the next day. And, so it has. Water will continue to be wet, and guess what, it has. Quito is the capital of Ecuador, and it is! That's a pretty good record right there!

It was also conventional wisdom that witches cause disease, time is absolute, the sun and planets orbit the Earth, humans are animated by a vital essence, etc...

Sometimes conventional wisdom is wrong, and most often, it is right.

If it didn't, we would not be around to discuss it.

That's a weird criterion for justification, considering how wildly inaccurate conventional knowledge has been in the past. It seems to me that whether or not something is conventional depends on its popularity and not on its accuracy.

That hasn't been demonstrated.



Are you saying that whether or not the Sun orbits the Earth is critical for our survival? If we were wrong about that then we wouldn't be here? That seems obviously false.

We can only be certain that something does not exist in the universe if its existence is contradictory to the physical laws of the universe, a rock so big that it cannot be moved or cannot move, for example (?). Even then, the idea of such a thing will exist in the mind. Therefore, we cannot say that unicorns do not exist because their existence is not contradictory to the known physical laws of the universe. Unicorns may certainly exist in the universe somewhere, if not on earth. We may not even say that a unicorn has not existed on the earth at some time in the past, and certainly there is more evidence in support of their existence than in rejection of their existence.

To reject the existence of an entity, we must first have the idea of that entity in our minds, must conceive it clearly with all its properties and attributes. It must exist in the mind before it's existence in reality (in the universe) can be rejected. Therefore, in the broadest sense of the question, it is impossible for anything not to exist, if its existence may be questioned.

As for the existence of entities in the universe (or multiverse?), we must be specific with regard to the space-time location of the entity in question, unless its existence contradicts the physical laws of the universe. Otherwise, almost anything can exist somewhere as far as we may know.

Samm

No. What I said was that if conventional wisdom had not be right in the main, we would not have survived.

The problem with your argument is that most conventional wisdom isn't relevant to our survival. Our conventional wisdom about which berries to eat is right for the most part and if it weren't then we wouldn't have survived. However, most of the things worth arguing about are more intellectual than that.

If unicorns exist, how would their existence be explained. How would they have evolved, and from what? What would their DNA be like?