[bduerst]

Except you can observe a bank robbery, so that analogy is just a self-serving hypothetical.

I think psychics are a bunch of baloney too, but by definition the supernatural is not natural and not provable/disprovable. Let's not pretend that the act of disproving has some magic reach because then psychics or creationists or whoever will latch onto that overreach as a defense.

[greiskul]

And why can't you observe a psychic? And write down what they say/predict? And make tests based on that?

If we can interact with something, even indirectly, we can perform experiments on it.

[scott_s]

As I said above, you're right in that we can't prove a negative. But it's not a claim outside of science. They make claims which can be tested. When tested, their claims fail. When you repeat that enough times, you have amassed an incredible amount of negative evidence. When the body of negative evidence becomes overwhelming, it's reasonable to conclude that thing likely does not exist.