I've heard atheists insist that things be scientifically testable to be true or believed, but this is silly and dishonest.
There are many things which people believe, such as the existence of historical figures such as Julius Caesar, which aren't scientifically testable, but would be absurd not to believe. And it's not like testability guarantees that something is true either. It's merely a method of reducing the possibility of falsehood, similarly to how court trials don't guarantee that people are rightfully or wrongfully convicted to begin with.
To me, this just seems like a cop-out by atheists who don't want to believe in the existence of a God. Atheists will demand a specific standard of evidence for things they don't want to believe in, such as the existence of God, while not demanding that same standard of evidence for other things. Such as not demanding that the same standard of evidence of the existence of God be applied to believing in the existence of historical figures like Julius Caesar.
And some atheists would likely refuse to believe in God no matter what evidence was presented to them, just because they don't want to. If I didn't want to believe in the existence of Julius Caesar, I could simply demand that a video recording of Julius Caesar's life from birth until death be provided, and of course it would be impossible to provide such evidence. Therefore, there would be no reason to believe in Julius Caesar.
There are many things which people believe, such as the existence of historical figures such as Julius Caesar, which aren't scientifically testable, but would be absurd not to believe. And it's not like testability guarantees that something is true either. It's merely a method of reducing the possibility of falsehood, similarly to how court trials don't guarantee that people are rightfully or wrongfully convicted to begin with.
To me, this just seems like a cop-out by atheists who don't want to believe in the existence of a God. Atheists will demand a specific standard of evidence for things they don't want to believe in, such as the existence of God, while not demanding that same standard of evidence for other things. Such as not demanding that the same standard of evidence of the existence of God be applied to believing in the existence of historical figures like Julius Caesar.
And some atheists would likely refuse to believe in God no matter what evidence was presented to them, just because they don't want to. If I didn't want to believe in the existence of Julius Caesar, I could simply demand that a video recording of Julius Caesar's life from birth until death be provided, and of course it would be impossible to provide such evidence. Therefore, there would be no reason to believe in Julius Caesar.

