As the productive forces expand, through greater skill on the part of the worker, through discoveries of new raw material and markets, through the invention of new labour processes, tools and machines, and through the better organisation of trade and exchange, so that the material basis or the economic foundation of society is altered, then the old conditions of production cease to promote the interests of production. For the conditions of production: the former social classes, the former laws, State institutions, and intellectual systems were adapted to a state of the productive forces which is either in process of disappearing, or no longer exists. The social and intellectual superstructure no longer corresponds to the economic foundation. The productive forces and the conditions of production come into conflict with each other. This conflict between the new realty and the old form, this conflict between new causes and the obsolete effects of bygone causes, begins gradually to influence the thoughts of men. Men commence to feel that they are confronted with a new external world, and that a new era has been opened. Social divisions acquire a new significance: classes and sections which were formerly despised gain in social and economic power; classes which were formerly honoured decline. While this transformation of the social foundation is proceeding, the old religious, legal, philosophical, and political systems cling to their inherited positions, and insist on remaining, although they are obsolete and can no longer satisfy mental needs. For human thought is conservative: it follows external events slowly, just as our eye perceives the sun at a point which the sun has in reality already passed, as the rays require several minutes of time in order to strike our optic nerves. We may recall Hegel's fine metaphor: "The Owl of Minerva begins its flight only when twilight gathers." However late, it does begin. Great thinkers gradually arise, who explain the new situation, and create new ideas and trains of thought which correspond to the new situation. The human consciousness gives birth to anxious doubts and questionings, and then new truths; leading to differences of opinion, disputes, strifes, schisms, class struggles, and revolutions. In the next chapter we will consider more closely the class struggle between Labour and Capital. Meanwhile, we will look at the class struggle generally.