Direct knowledge of your emotions.
Freewill is simply a feeling you get when you make a decision.
In the same exact way, someone could argue that their god (Krishna) is REAL because they can feel Krishna's love in their heart.
I know my god loves me because I experience a feeling of (god's) love.
Would you accept this as "incontrovertible evidence" of the existence of Krishna?
RE: Critique of Critique