Quote by Peter Kreeft

“5. You can’t prove a lot of things that it would be lunacy to deny—for instance, that human reason is trustworthy, that it is not being hypnotized by a demon at every moment. Of course that thought is ridiculous, but can you prove it isn’t true? No, because you’d have to use your reason to prove it, and that means trusting the validity of reason, and that is assuming the very thing you’re supposed to be proving, “begging the question”. If a thousand prisoners are all on trial, no one of them has the right to be the judge and declare all one thousand innocent. If all acts of reasoning are on trial and need to be justified, no one of them has the right to do that justifying. So you can’t prove the validity of reasoning. So not everything has to be proved, for not everything can be proved. So the demand to prove the existence of spirit, and the refusal to believe it just because it isn’t proved, is an unfair demand.”