Karl Marx

“ In its further development, materialism becomes one-sided. Hobbes is the man who systematizes Baconian materialism. Knowledge based upon the senses loses its poetic bloom, and Becomes the abstract experience of the mathematician. The physical movement is sacrificed to the mechanical or mathematical; geometry is proclaimed as the chief science. Materialism takes to misanthropy. In order to overcome misanthropic, fleshless spiritualism on the latter's own ground, materialism must mortify its own flesh and turn ascetic. ”

“ Pierre Bayle not only prepared the way for the acceptance in France of the materialism and philosophy of healthy common science through the sceptical disintegration of metaphysics. He announced the atheistic society which was soon to come into existence, inasmuch as a society of avowed atheists could exist, as an atheist could be an honest man, as man was not degraded by atheism, but by superstition and idolatry.
In the words of a French writer, Pierre Bayle was "the last metaphysician in the sense of the seventeenth and the first philosopher in the sense of the eighteenth century." ”

“ Just as Cartesian materialism branches into natural science, so the other tendency of French materialism merges directly into socialism and communism.
No special acuteness is required to perceive the necessary connection of the original goodness and equally intelligent endowment of men, of the omnipotence of experience, custom and education, the influence of external circumstances on men, the extreme importance of industry, the justification of enjoyment, etc., with communism and socialism. ”

“ If man is formed by circumstances, then it is only in society that he develops his real nature, and the strength of his nature must be measured, not with the strength of the isolated individual, but with the strength of society.
These and similar sentences may be found almost word for word in the writings even of the oldest French materialists. This is not the place to criticize them. Significant of the socialist tendency of materialism is Mandeville's (one of the older English pupils of Locke) apology for vice. He shows that vice is indispensable and useful in present-day society. ”

“ All science is based upon experience and consists in subjecting the data furnished by the senses to a rational method of investigation. Induction, analysis, comparison, observation, experiment, are the chief instruments of such a rational method. ”

“ Hobbes, as Bacon's continuator, argues that if the senses furnish men with all knowledge, then concepts and ideas are nothing but phantoms of the material world more or less divested of their sensual forms. All philosophy can do is to give these phantoms names. ”

“ If man is not free in the materialistic sense, that is to say, is free, not by reason of his negative strength to avoid this and that, but by reason of his positive strength to assert his true individuality, then man must not punish the crimes of individuals, but destroy the anti-social breeding-places of crime, and afford to each person sufficient social scope for the expression of his or her individuality. ”

“ Bodies, being, substance are but different terms for the same reality. One cannot separate thought from matter that thinks. It is the substratum of all changes. The word infinite is meaningless unless it signifies the capacity of our minds to perform an endless process of addition. As only material things are perceptible and knowable, nothing can be known about the existence of God. ”

“ If man receives all his impressions and forms all his conceptions from the world of sense, and derives his experiences from the world of sense, it follows that the empirical world ought to be so constructed as to offer a wealth of truly human experiences. ”

“ The former, viz., the mechanical materialism, is absorbed in French natural science. The French materialism which derives directly from Descartes does not concern us particularly, any more than the French school of Newton and French natural science generally.
Only this much need be said. In his physics Descartes invested matter with self-creative power, and he conceived mechanical movement to be its vital act. He separated his physics completely from his metaphysics. Within his physics matter is the only substance, the only basis of being and perceiving. ”

“ It would, however, imply a contradiction if, on the one hand, we contended that all ideas had their origin in the world of senses, and, on the other hand, that a word was worth more than a word; that besides the individual beings known to us by our senses, there existed also beings of a general nature. An immaterial substance is rather the same absurdity as an immaterial body. ”