Note 16 — PART IV SUMMARY AND CONCLUSION

Let me here parenthetically remind you that again (as I observed in an earlier lecture) the Naturalism of which I speak is Naturalism in what, from our present point of view, must be regarded as its most plausible shape. Those who have followed, even at a distance, the trend of biological thought are aware that many naturalists of the highest authority are shaken in their allegiance to natural selection. They do not, indeed, exclude it from the evolutionary drama, but they reduce its rôle to insignificance. Why then, you may ask, do these lectures so constantly refer to selection, but say never a word about other theories of organic evolution?

The answer is that selection, and only selection, really imitates contrivance. Other theories may deal, and do deal, with variation and heredity. But selection alone can explain adjustment; whence it follows that selection alone can imitate design.