Mens ideas are the most direct emanations of their material state. – Karl Marx
The ideas of the ruling class are in every epoch the ruling ideas, i.e., the class which is the ruling material force of society, is at the same time its ruling intellectual force. – Karl Marx
Capital is reckless of the health or length of life of the laborer, unless under compulsion from society. – Karl Marx
Mankind always sets itself only such tasks as it can solve; since, looking at the matter more closely, we will always find that the task itself arises only when the material conditions necessary for its solution already exist or are at least in the process of formation. – Karl Marx