If Marx says that we confirm our existence by our actions, then if we can't or don't desire to act, but still think, then we don't actually exist? What about creativity or desire, or even our reason, morality and values, where do these come from? German filosofers say that we exist by what we think and believe etc., but this is also wrong because we have a body for a reason, that is, only if you believe in reason. We are not machines or robots and we are definitelty not ghosts roaming the earth. So what are we? We are humans made in the likeness of God, there is no other explanation that corrects these other filosofies and unites them perfectly. By the way this sovereign TRUTH existed way before those other filosofies. You need to stop being prideful, forget yourself and let yourself be saved, loved and taken care of by God and His everlasting perfect grace, you will never regret it because you know that's what you are supposed to do.