いわゆる「原型」思想について : 動物学における「比較」概念の問題

Abstract

Human being has a strong tendency to look for the 'Prototype'. The search for the Prototype has been the source of biological studies also. It is certain that this tendency derives from our method of recognition by comparison. When resemblance and difference are recognized among objects, we are tempted to suppose a common ancestral type of those objects. This ancestral type is perceived as the Prototype. Wolfgang von Goethe, who proposed the concept of Typus or Urtypus, appears to have believed in real existence of Protoplant (Urpflanze). Later, however, he renounced this idea and realized that the Urpflanze was only a conceptual Idealtypus. But in the field of biology the search for really existing prototype has been continued, according to the concept of homology. The concept of homology and phyletic evolution leads directly to the idea of Prototype. But in the comparative morphology which represents the most typical comparative way of biology, the Prototype proposed by a researcher often differs from that proposed by another. This denies the absoluteness usually attributed to the Prototype. The most relevant problem for the comparative biology is to explain why the living beings are so diverse. Comparison guided by the concept of homology will no longer be effective for the analysis of this problem, because it can only show the process and only in a tentative way but say nothing about 'Why'. We should now rely on the method which I call 'Comparison by analogy'. Search for Prototype is no more than a dream of innocent romantists.