Who wrote the definition of insanity in Far Cry 3?

The definition of insanity in Far Cry 3 is not actually attributed to any specific person in the game.

It's presented as a common saying or proverb, though with a slight twist.

Here's the full quote from the game:

"Insanity is doing the same thing over and over again and expecting different results."

While this is a common saying often attributed to Albert Einstein, there's no official source for this, and it's likely just a popularization.

The important thing is that Far Cry 3 uses the saying as a thematic element in the story, highlighting the cyclical nature of violence and the protagonist's descent into madness.