I repeat, then: One may think logically without having attended any lectures on logic, just as one may raise potatoes without a scientific knowledge of agriculture. It was possible to invent the thermometer, to clearly distinguish between sounds and colors, and a hundred other things, without having explained the faculty of discrimination. But the most abstract distinctions, such as beginning and end, word and meaning, body and soul, man and animal, matter and force, truth and error, presuppose for their explanation a logical explanation of their interconnection with our intellect. EIGHTH LETTER Dear Eugene: Logic is going through the same experience as economics. The economists of the capitalist era talk solely of the means and ways by which profit and surplus value may be increased. They discuss only its relative size, its increase or decrease. But the thing itself, its origin and descent, is not discussed. It is passed in silence that profit is extracted from labor power by paying less for a day's work than is produced by it. The gentlemen talk only of the "wealth of nations," but not of their poverty. And though this was due to ignorance in the beginning, it has later become sheer roguery. The formal logicians are as ignorant as they are roguish, when they persist in discussing the intellect or thought in the traditional manner as if they were isolated things, while ignoring the necessary connection of the object of the logical study with the world of experiences. This interconnection leads to an explanation of truth and error, of sense and nonsense, of god and idols, and this is very inopportune for the professors. For this reason this unwelcome problem is handed over to the mystical departments, to metaphysics and religion, so that these venerable pillars of official wisdom may continue their services to the ruling classes. I have already stated in my letters that the kernel of my discussion turns on the distinction between formal and what I call proletarian logic. The formal logicians treat the intellect as a thing "in itself," while I express in many different ways the fact that the intellect does not exist by itself, but is interconnected with all things and with the universe. That intellect has indeed a transcendental leaning, which seeks vent by trying to exclude now music, now language, now itself, now some other fetich from the universal interrelation. But the science of the mind teaches that the brain watching its own activity finds out that all affirmations and negations, assertions and contradictions, belong to the one omnipotent world mechanism, which keeps them stored within itself and which is actually truth and life. Inasmuch as the human brain is of the same nature as this automatic universal being and interconnected with it, logic is at the same time religion, metaphysics, and world wisdom.[4]