Without getting into the economic or political side of Karl Marx, I will mention an important contribution he made to philosophy, which was to emphasize the importance of action.
He said, “Philosophers have only interpreted the world in various ways, but the real task is to alter it.”
His idea was that the truth of a thought must be demonstrated in practice. Without practice, ideas are only scholastic. Philosophers have pursued knowledge with the assumption that knowledge is a fixed entity which the knower is required to discover. But neither the knower nor the thing to be known are static. They are both constantly changing and adapting to one another. This is the dialectical process, according to Marx, who was influenced by Hegel.
In practice, it is possible to know a thing to be true or false, and still to act in such a way that contradicts what you know. To give a simple example (but keep in mind the wider application of this idea), you can know that texting while driving is dangerous, but still do it. And even if you manage to put into practice what you know, the mere passage of time will be enough to reverse the progress you have made. Whether you are trying to curb a bad habit, or construct a good one, it is not enough to know, and it is not enough to act – you must retain conviction in your knowledge, and consistency in your action.
The problem is that changing circumstances, interactions with people, and recurring anxiety, will usually be enough to sway you off track, so the feeling that you have is that you are engaged in a losing battle that will never end.
This is all deeply discouraging, especially when you consider that you are further haunted by endless cognitive biases, errors in judgement, and profound ignorance, and surrounded by creatures that share and often reinforce all that is lacking within you.
But I think it is here that Marx’s idea can be useful, because in the dialectical process that he outlines, there is no constant self and there is no fixed knowledge. If the two are constantly changing, then self-transformation and the reduction of cognitive errors becomes possible. You may never reach a perfect state in which you have perfect knowledge of the world, and all your actions match exactly what you know, but the dialectic presupposes that an approximation to something better (or worse) is taking place.
The mistake would be to be discouraged by a self-invented sort of idealism which you will inevitably betray. Do not expect that you will be consistent in your behavior once you have discovered something is true or false. But do expect that you will be more consistent than you once were, only if you make the effort, only if you act out what you already know.