If indeed there is such a thing as free will then by definition it must be supernatural. If, on the other hand, all of our actions are determined by a intricately complex set of natural causes and effects then our power of decision is merely an illusion. How can we tell if free will exists? Simple: We all make mistakes. Programmed automatons can’t, you know, no matter how sophisticated. So-called “computer-error” is actually user error, programmer error, manufacturer error or environmental causes outside the computer’s control. How do I know I am right about all this? Because I can’t be in error without proving myself correct. If I am a programmed automaton and it is not my error, then whose is it? Free will is necessary to make a mistake.
A man who is eating or lying with his wife or preparing to go to sleep in humility, thankfulness and temperance, is, by Christian standards, in an infinitely higher state than one who is listening to Bach or reading Plato in a state of pride.