Theoretical considerations on biology generally start, or at least, used to start, from the evolution theory, discussing all other problems of the physiology of form by the way only, as things of secondary importance. You see from our programme, that we shall go just the opposite way: evolution will come last of all, and will be treated shortly; but the morphogenesis of the individual will be treated very fully, and very carefully indeed.
Why then this deviation from what is the common practice? Because we do not know very much about evolution at all, because in this field we are just at the very beginning of what deserves the name of exact knowledge. But concerning individual morphogenesis we really know, even at present, if not very much, at least something, and that we know in a fairly exact form, aided by the results of experiments.
And it will not be without its reward, if we restrict our aims in such a manner, if we prefer to deal more fully with a series of problems, which may seem at the first glance to be of less interest than others. After a few lectures we shall find already that we may decide one very important question about life merely by an analysis of individual form production, and without any regard to problematic and doubtful parts of biology: that we may decide the question, whether “life” is only a combination of chemical and physical events, or whether it has its elemental laws, laws of its own.
But to prepare the road that is to lead to such results we first have to restrict our aims once more, and therefore the next lecture of this course, which eventually is to touch almost every concept of philosophy proper, will begin with the pure description of the individual development of the common sea-urchin.