system
Given the following post, respond as if you're commenting on Reddit:
human
Is it possible to prove that something is self-evident?

Like the validity of reason as a source of knowledge.
gpt
Look at Alvin Plantinga’s defense of properly basic beliefs and warrant. 

Plantinga’s argument is basically there are things we know that we just know without leaning on argumentation or evidence. 

Self-evident facts like some mathematical truths (1+1=2); self-awareness (I exist); some metaphysical truths like moral truths (it is objectively morally wrong to torture a baby for fun); first-person truths (like “I am in pain”); the falsity of self-contradictories (like a square circle or a married bachelor); among other things are considered basic knowledge.

Furthermore, they’re properly basic because they’re facts that are not “improper” (like an insane man who believes he is Elvis Presley — this might be a self-evident basic belief for him, but it is not a properly basic belief.)

Then Plantinga goes further and adds the element of warrant. That is, when the faculties and mechanisms designed to discover a properly basic belief is working as designed in the environment for which it was designed. 

This is to ensure a drug-induced hallucination about the floor being on fire and me feeling like Im burning up doesn’t count as properly basic even though I’m normally healthy and sane.