Lecture I

Even at this stage our contemporaries fail to think clearly enough. I will explain by an example, how great is the leap from kinematics into mechanics. The kinematical phenomena can still take place entirely within a space of our own thinking; mechanical phenomena on the other hand must first be tried and tested by us in the outer world. Our scientists however do not envisage the distinction clearly. They always tend rather to confuse what can still be seen in purely mathematical ways, and what involves realities of the outer world. What, in effect, must be there, before we can speak of a parallelogram of forces? So long as we are only speaking of the parallelogram of movements, no actual body need be there; we need only have one in our thought. For the parallelogram of forces on the other hand there must be a mass—a mass, that possesses weight among other things. This you must not forget. There must be a mass at the point a, to begin with. Now we may well feel driven to enquire: What then is a mass? What is it really? And we shall have to admit: Here we already get stuck! The moment we take leave of things which we can settle purely in the world of thought so that they then hold good in outer Nature, we get into difficult and uncertain regions. You are of course aware how scientists proceed. Equipped with arithmetic, geometry and kinematics, to which they also add a little dose of mechanics, they try to work out a mechanics of molecules and atoms; for they imagine what is called matter to be thus sub-divided, In terms of this molecular mechanics they then try to conceive the phenomena of Nature, which, in the form in which they first present themselves, they regard as our own subjective experience.