Hegel was a man of vision who belied his own insights in order to assure the Prussian monarchy that its existence was part of the divine plan an, indeed, its final expression. Since the reasons he adduced were the most transparent rationalizations, both his system and his method fell into disrepute. Attempting to prove that all of existence was rational, therefore necessary, and, therefore, good, he failed to make the existence of any particular thing intelligible. There was not much difference between his ruthless optimism which assured the rising German bourgeoisie that this was the best of all possible worlds and the sentimental pessimism of his arch-enemy, Schopenhauer, who held it was the worst. For neither system admitted that the world could significantly change on way or the other. For Hegel, change was merely appearance, for Schopenhauer, illusion.

Marx was an empiricist. If change was not real, nothing was real. Even if permanence and invariance were characters of existence, they could only be recognized in change and difference. The dialectic method of Marx is a way of dealing with what is both constant and variable in every situation. It is the logic of movement, power, growth and action.
- Sidney Hook
- from Towards the Understanding of Karl Marx p.148

This may seem like an odd question, but does anyone know if Marx ever commented on Schopenhauer's philosophy (or vice versa)? I assume Marx would feel Schopenhauer was pessimistic and Schopenhauer would feel Marx was another silly Hegelian but I have no idea if they ever made comments on one another. Despite this, as a philosophy student, I imagine Marx would have read Schopenhauer's magnum opus, even though Schopenhauer held such disdain for Hegel's dialectic.

The reason I ask is I cannot help but draw ontological lines between Schopenhauer's concept of the 'will to life' in The World as Will and Representation and Marx's concept of 'need', specifically 'natural need', in the 1844 Manuscripts. Although Schopenhauer felt that the 'will' is a dark and miserable drive that can never be completely fulfilled for humans (and thus suppressed) and Marx felt humans should create a 'wealth of needs' collectively, both philosophers felt that these drives must be objectified externally to be actualized.

Marx tries to show how social change arises from the interacting processes of nature, society and human intelligence. From objective conditions, social and natural (thesis), there arise human needs and purposes which in recognizing the objective possibilities in the given situation (antithesis) set up a course of action (synthesis) designed to actualize these possibilities.
- p. 158 of the same text