VI. The Present State of Philosophy and Science

At that time, Julius Robert Mayer, and later, independently of him, Helmholtz, discovered what has since been called the doctrine of the mechanical equivalent of heat, the so-called conservation of living force. Now, soon after that had happened, Helmholtz built another theory on this theory of the conservation of living force, which was then also widely accepted and is still considered indisputable by many today: namely, that in the interplay of living the interplay of living forces in the universe, there is a constant conversion of some other, let us say, of the processes in the world-leading living forces, be they the forces of magnetism or electricity, be they other purely mechanical forces, into heat. Now, in the sense of the so-called Carnot cycle, it is never possible to completely carry out the process of converting energy into heat while maintaining the same energy quantum. It must be said that it is never possible to convert all heat back into living force. Incidentally, if I wanted to describe this so-called second law of thermodynamics, I would have to give a few lectures on it. But today I only want to characterize it. It is not important that everything you can learn about it is also said here. In the sense of the second law of the mechanical theory of heat and in the sense of what Hermann Helmholtz made of it in the 1850s, it is the case that in all the processes of our existence, ultimately, in the conversion of heat into power, there must be a quantum of heat that can no longer be converted back into another power. Consequently, all our physical-mechanical processes must ultimately proceed in such a way that their forces are converted into heat. And since there is always a residue of heat, these processes must ultimately come to an end in a goal that consists in all other forces having been converted into heat, that all living forces, so to speak, will ultimately have been converted into heat. We would thus have reached what we can call the heat death of our earth. Of course, no other process could take place if everything were converted into heat. Thus, so to speak, physical thinking up to the middle of the 19th century runs into this law, runs into the statement that, if one consulted what could be physically thought at that time, was actually quite correct: it runs into the statement of the heat death of our earth. And the only consolation that Helmholtz found was this: It is still a long time away, and no one has to fear that the heat death will affect them so soon. And everything we can observe shows us this process to such a small extent that we can hope that life will continue for millions of years without the heat death affecting the Earth. For those who proceed with more thorough knowledge, this remains just a philistine consolation.