1. During recent years mathematicians and philosophers have been much occupied in analysing the fundamental conceptions on which the different sciences are based, with the result that many things which were formerly regarded as quite simple and axiomatic can no longer be regarded as such. The tendency has, of course, been to make definitions as precise as possible, and to make descriptions of phenomena approximate to reality as we know it, and not to a preconceived idea of what the description ought to be.
Many difficulties arise, however, in a careful examination of the fundamental concepts of any science, and this is soon found to be the case when we commence to examine the ideas of space and time which are fundamental in all physical and metaphysical enquiries.
In the case of time, for instance, it is found that we have to examine the connection between time as it is known to us by the mind's experience, i.e., psychological time, and time as it is measured by the course of physical phenomena, i.e., physical time.
With regard to psychological time, it has been contested that it is purely qualitative, in other words that we are quite unable to decide intuitively whether two intervals of time are equal or not.[1] This means that
- ↑ See for instance Poincaré, "La Valeur de la Science," ch. II.
June 15th, 1910.
