↑ P. Ăng- ghen: Biện chứng của tự nhiên, Nhà xuất bản Sự thật, Hà Nội, năm 1971, trang 367
↑ Triết học Mác – Lenin, chương trình cao cấp, tập II, Học viện chính trị quốc gia Hồ Chí Minh, Nhà xuất bản Chính trị quốc gia, Hà Nội, năm 1994, trang 6
↑ V. I. Lenin, "Materialism and Empirio-Criticism", Collected Works, Vol. 14, p. 1. Trích: We ask, is a man given objective reality when he sees something red or feels something hard, etc., or not? This hoary philosophical query is confused by Mach. If you hold that it is not given, you, together with Mach, inevitably sink to subjectivism and agnosticism and deservedly fall into the embrace of the immanentists, i.e., the philosophical Menshikovs. If you hold that it is given, a philosophical concept is needed for this objective reality, and this concept has been worked out long, long ago. This concept is matter. Matter is a philosophical category denoting the objective reality which is given to man by his sensations, and which is copied, photographed and reflected by our sensations, while existing independently of them. Therefore, to say that such a concept can become “antiquated” is childish talk, a senseless repetition of the arguments of fashionable reactionary philosophy. Could the struggle between materialism and idealism, the struggle between the tendencies or lines of Plato and Democritus in philosophy, the struggle between religion and science, the denial of objective truth and its assertion, the struggle between the adherents of supersensible knowledge and its adversaries, have become antiquated during the two thousand years of the development of philosophy?
