p As a rule, idealists reject the objective existence of matter. Some hold that it does not exist at all, but was invented by materialists to prove their atheistic conclusions (Berkeley). Others declare it to be a totality of sensations (Mach). Still others represent it as a result of the development of consciousness, as something dependent on or derived from it (Hegel).

p All the materialists, however, recognise the real, objective existence of matter. In the course of history, materialist views on the substance of matter have differed considerably. Ancient philosophers were inclined to identify matter with the most widely spread substances or phenomena, such as water (Thales), air (Anaximenes), or fire (Heraclitus). Later, matter was believed to be an infinite multitude of various invariable elements, such, for instance, as the so-called “seeds of things" (Anaxagoras), or atoms (Democritus). The 18th-century French materialists, Feuerbach, and other thinkers considered matter to be the totality of immutable atoms that made up all objects existing in the world.

p To view matter as a totality of atoms or substances is both narrow and false. This way of thinking is associated with definite forms of the existence of matter, and raises their inherent properties and states to an absolute. It is unable, therefore, to embrace the entire totality of phenomena occurring in the world and the endless variety of the forms of being.

p The inadequacy of the above conception of matter was revealed strikingly during the crisis that gripped natural science at the turn of the 20th century, following the discovery of the electron and radioactivity. The discovery of the electron showed, in particular, that the atom is not immutable and eternal as previously believed, but consists of smaller particles-electrons. Moreover, it was discovered that the mass of an electron is not invariable, but is a direct function of its velocity. Yet it had been believed that the mass of an atom was constant. This notion gave rise to the idea that atoms, and consequently matter, were eternal and indestructible.

p The collapse of the notions that atoms were indivisible and eternal and that the mass of bodies was constant and indestructible evoked doubts as regards the objective existence of matter and led to the conclusion that it was disappearing. The logic was as follows: if an atom is divisible, if it disintegrates into electrons whose mass depends on motion, then matter, as something basic underlying all being, disappears and turns into motion. Similar conclusions followed from the discovery of radioactivity. The 97 radioactive decay of uranium, and later of radium, was taken to mean the transformation of matter into motion, or pure energy. Idealists were quick to take this up. They began to assert that the latest advances of natural science refuted materialism, having shown that matter did not exist and had been invented by materialists.

It was necessary to generalise the above scientific discoveries, to bring them in the line with dialectical materialism and refute those idealists who caught at these discoveries. Lenin undertook to solve this problem.