[London,] 30 May 1873

Dear Moor,

This morning in bed the following dialectical points about the natural sciences came into my head:

The object of science: matter in motion, bodies. Bodies cannot be separated from motion, their forms and kinds can only be apprehended in motion; nothing can be said about bodies divorced from motion, divorced from all relation to other bodies. Only in motion does the body reveal what it is. Hence natural science obtains knowledge about bodies by examining them in their relationship to each other, in motion. Cognition of the various forms of motion is cognition of bodies. The investigation of these various forms of motion is therefore the chief object of the natural sciences.”

1. The simplest form of motion is change of place (within time, to do old Hegel a favour)— mechanical motion.

a) There is no such thing as the motion of a single body, but relatively speaking one can talk of a falling body in such terms. Motion towards a centre common to many bodies. However, as soon as a single body moves in a direction other than towards the centre, the laws of falling still apply, it is true, but they are modified ©

a Samuel Moore - > Marginal note by Carl Schorlemmer: ‘Very good; my own view. C. S.’ - © Marginal note by Carl Schorlemmer: ‘Quite right.’

First page of Engels’ letter to Marx of 30 May 1873

b) into the laws of trajectories and lead directly to the interaction of several bodies—planetary, etc., motion, astronomy, equilibrium—temporarily or apparently to motion itself. The real result of this kind of motion, however, is ultimately always the contact of the moving bodies; they fall into one another.

c) Mechanics of contact—bodies in contact. Ordinary mechanics, levers, inclined planes, etc. But this does not exhaust the effects of contact. Contact is manifested directly in two forms: friction and impact. It is a characteristic of both that, at certain degrees of intensity and under certain conditions, they give rise to new effects, no longer of a merely mechanical nature: heat, light, electricity, magnetism.

2. Physics proper, the science of these forms of motion, establishes the fact, after investigating each form of motion separately, that they merge into one another under certain conditions, and ultimately discovers that given a certain degree of intensity, which varies for different moving bodies, they all produce effects that transcend physics; changes in the internal structure of bodies— chemical effects.

3. Chemistry. In the case of the preceding forms of motion it was more or less immaterial whether the bodies under investigation were animate or inanimate. In fact inanimate objects revealed the nature of the phenomena involved in their greatest purity. Chemistry, on the other hand, can only discover the chemical nature of the most important bodies by using substances deriving from the life process. Its principal task is increasingly that of producing these substances synthetically. It forms the transition to the science of organisms, but the dialectical point of transition can only be constructed when chemistry has effected the real transition or is on the point of doing so.*

4. Organism—for the present I shall not indulge in any dialectical speculations on the subject.”

Since you are at the very centre of the natural sciences there, you will be in the best position to judge whether there is anything in it or not.

Your F. E.

a Marginal note by Carl Schorlemmer in English: ‘That’s the point!’ - > Marginal note by Carl Schorlemmer: ‘Nor shall I. C.S.’

If you think I am on to something, don’t tell anyone about it lest some rotten Englishman or other makes off with it. Working it all out will take a long time yet.