The present part of this book, comprising Chapters VIII-XI, will be devoted to working out such a conception of matter. An example will thereby be given of how Goethe's method of acquiring understanding of natural phenomena through reading the phenomena themselves may be carried beyond his own field of observation. There are, however, certain theoretical obstacles, erected by the onlooker-consciousness, which require to be removed before we can actually set foot on the new path. The present chapter will in particular serve this purpose.

The following description will show that, directly we free ourselves from the onlooker-limitations of our consciousness in the way shown by Goethe - and, in respect of the present problem, in particular also by Reid - the ideal relationship between the two theorems is seen to be precisely the opposite to the one expressed in the above statement. The reason why we take pains to show this at the present point of our discussion is that only through replacing the fallacious conception by the correct one, do we open the way for forming a concrete concept of Force and thereby for establishing a truly dynamic conception of nature.

We now submit the formula F=ma to the same scrutiny. If we attach to the factor a on the right side of the equation a definite quality, namely an observable acceleration, the other factor in the product is permitted to have only the properties of a pure number; F, therefore, can be only of the same nature as a and must itself be an acceleration. Were it otherwise, then the equation F=ma could certainly not serve as a logical link between the Velocity and Force parallelograms.

This is all we can discover empirically regarding the mutual relationships of three forces engaging at a point.

Science, since Galileo, has been rooted in the conviction that the logic of mathematics is a means of expressing the behaviour of natural events. The material for the mathematical treatment of sense data is obtained through measurement. The actual thing, therefore, in which the scientific observer is interested in each case, is the position of some kind of pointer. In fact, physical science is essentially, as Professor Eddington put it, a 'pointer-reading science'. Looking at this fact in our way we can say that all pointer instruments which man has constructed ever since the beginning of science, have as their model man himself, restricted to colourless, non-stereoscopic observation. For all that is left to him in this condition is to focus points in space and register changes of their positions. Indeed, the perfect scientific observer is himself the arch-pointer-instrument.

Let us begin by describing briefly the content of the two theorems in question. In Fig. 1, a diagrammatical representation is given of the parallelogram of movements. It sets out to show that when a point moves with a certain velocity in the direction indicated by the arrow a, so that in a certain time it passes from P to A, and when it simultaneously moves with a second velocity in the direction indicated by b, through which alone it would pass to B in the same time, its actual movement is indicated by c, the diagonal in the parallelogram formed by a and b. An example of the way in which this theorem is practically applied is the well-known case of a rower who sets out from P in order to cross at right angles a river indicated by the parallel lines. He has to overcome the velocity a of the water of the river flowing to the right by steering obliquely left towards B in order to arrive finally at C.

Our present investigation has done no more than grant us an insight into the process of thought whereby the consciousness limited to a purely kinematic experience has deprived the concept of force of any real content. Let us look at the equation F=ma as a means of splitting of the magnitude F into two components m and a. The equation then tells us that F is reduced to the nature of pure acceleration, for that which resides in the force as a factor not observable by kinematic vision has been split away from it as the factor m. For this factor, however, as we have seen, nothing remains over but the property of a pure number.

Let us now heed the fact that nothing in this group of figures reveals that in each one of these trios of lines there resides a definite and identical geometrical order; nor do they convey anything that would turn our thoughts to the parallelogram of velocities with the effect of leading us to expect, by way of analogy, a similar order in these figures. And this result, we note, is quite independent of our particular way of procedure, whether we use, right from the start, a measuring instrument, or whether we proceed as described above.

The birth of the method of pointer-reading is marked by Galileo's construction of the first thermometer (actually, a thermoscope). The conviction of the applicability of mathematical concepts to the description of natural events is grounded in his discovery of the so-called Parallelogram of Forces. It is with these two innovations that we shall concern ourselves in this chapter.

It is essential to observe that the content of this theorem does not need the confirmation of any outer experience for its discovery, or to establish its truth. Even though the recognition of the fact which it expresses may have first come to men through practical observation, yet the content of this theorem can be discovered and proved by purely logical means. In this respect it resembles any purely geometrical statement such as, that the sum of the angles of a triangle is two right angles (180°). Even though this too may have first been learnt through outer observation, yet it remains true that for the discovery of the fact expressed by it - valid for all plane triangles - no outer experience is needed. In both cases we find ourselves in the domain of pure geometric conceptions (length and direction of straight lines, movement of a point along these), whose reciprocal relationships are ordered by the laws of pure geometric logic. So in the theorem of the Parallelogram of Velocities we have a strictly geometrical theorem, whose content is in the narrowest sense kinematic. In fact, it is the basic theorem of kinematics.