This Existential Comics-like sketch popped into my brain while I was reading Capital. I'm not well-read enough to make their personalities and language very accurate, but I tried to get their ideas right.
Engels, Marx, Hegel, Descartes, and Spinoza are sitting together at table.
Engels: Thank you for coming to this meeting of enlightenment dialecticians. Today the topic of discussion will be “free will.” Does anyone want to start?
Descartes: Well, obviously we have free will because God is good, and he gave it to us. God created us and left us the world so that we could affect the world in ways that would decide whether we go to heaven.
Hegel: I agree to an extent, our free wills move forward history by making rational arguments advancing the world spirit. That does not mean we are just souls doing whatever we want. We pick rational choices in line with the dominant thinking of our society.
Marx: Religion may comfort people, but there is no god to give free will. Hegel’s sort of on track, but the limits on freedom are material not ideal. People have material conditions that greatly limit the choices they can make, but the masses ultimate move history forward, not simply ideas.
Descartes: What do you mean there’s no God? I literally proved it in my fifth meditation!
Marx: No, you didn’t, you idealist fool! There are no non-material things and nothing can be proved by pure reason.
Spinoza: I agree with Marx. We are all part of the one material world. However, that has implications for your argument too Karl. Our minds are material too, and therefore our actions are a result not only of outside conditions, but also the material that makes up our minds is also a part of God. Thus, we are ourselves nature acting out deterministically, and free will is an illusion.
Descartes: What God are you talking about?!
Engels: Ignoring Descartes, You are not wrong, though the wills of humanity still move forward history toward communism regardless of if they are free.
Spinoza: True enough.
Hegel: What do you mean forward to communism? I live in the end of history. There is nothing beyond constitutional monarchy.
Marx: You bourgeois idealist bastard!
Marx gets out of his seat and goes to flip Hegel on his head.
Engels: That’s enough everyone. He mutters under his breath. I should’ve picked a different topic.