The Fixed Type is apparent in all recorded human experience.
This is the argument based on human experience during the period of humanly recorded History, of which argument not nearly enough has been made.
For certainly 5000 years of this record types are fixed. That is not to say that maturity is not reached by growth, nor is it to say that a type cannot disappear. But it is an affirmation that the conceptions of ceaseless flux, of the absence of form, of no maturity in characteristics and nature, are baseless. As, indeed, the mere evidence of our senses and of common sense acting on that evidence, must convince anyone who prefers reality to print. Tell the plain man that there is no such thing as a fox or a salmon or a human being, and he will laugh in your face. And he will be quite right.
We are told that the 5000 years or so of recorded History (if we count prehistoric relics the period is probably longer) are so brief that they are a mere flash, and that we cannot observe in that tiny section of an immensely long period the slight process of change over which Natural Selection has been at work. We are under the illusion that types are fixed because the few thousand years over which we can compare them are as nothing compared with the whole period of development. Types only seem fixed to us in the same way as a revolving wheel seems at rest when discovered by a flash of lightning: the period of vision is too brief for the motion to be appreciated.
But people who talk like that have not made the very simple calculation of dividing the total period of a particular development by the few thousand years over which our direct experience stretches.
Take, for instance, the theory of Natural Selection as applied to ourselves. We know that over all these 5000 years the human body has not progressively changed. There have been various sorts of men, of course, and variations also round the normal. But the norm is set. Now even those who have indulged in the wildest guesswork to allow for development do not give true man more than 50,000 years.[[2]] Now, one-tenth is a very sufficient fraction by which to measure any movement. If so highly differentiated and co-ordinated an organism as man has been subject to unceasing slow transformation during 50,000 years, and will go on changing slowly through the next 50,000, then certainly in one-tenth of that period some considerable change should be marked. None is so marked. Man, throughout those 5000 years, at least, is a certainly Fixed Type, as his own records and portraiture show.
[2]. Not to burden the text, I give in this footnote a few of the main guesses. Sollas 15,000 from the beginning of the Magdalenian. Waldmeyer 15,000 to 20,000 for true man. Boulay 10,000. Mainage (a very high authority) 15,000 from the Chellean. Holst, less than 7,000.
2. The Second Argument from Evidence:
Geological record is entirely in favour of Fixed Types.
The geological record also shows us nothing but Fixed Types. Each may have come by a transition more or less rapid out of some other—but at any rate fixed they are, and the longer the time demanded by the modern geologist for his periods, the longer the Fixed Type can be proved to exist. Some few survive to-day from the very early days of life on this earth. It was hoped, when the theory of Natural Selection was first broached, that evidence would appear for continuous change. None has so appeared. On the contrary, the more fossil evidence we acquire the more definitely does it appear that the Fixed Type is the normal—indeed the only—recorded thing. Of connected transitional changes (perhaps because they were too rapid to affect the fragmentary record of the rocks) none has been discovered. There are plenty of intermediary forms: there is not one connected series of changing forms passing one into the other.