If everything is the result of previous factors, and nothing could have turned out differently, what is the point of making any argument about anything at all?

If everything is the result of previous factors, and nothing could have turned out differently, what is the point of making any argument about anything at all? You are relying on my free will: that I will focus my mind, read your argument, incorporate my experience, judge its truth using my reasoning faculty, and choose. Without free will, reason is impotent. Philosophers can’t agree or disagree because they have no choice in the matter. Free will is not about being able to choose any random thing at all. That would be like saying I’m not a human because I can’t will myself into becoming a banana peel.