The Probability of the Existence of a Self-Reproducing Unit

Abstract

IN his ‘Analytical Study’ of life and the multiplication of organisms,¹ Elsasser analyses the way in which the information is stored in the germ-cells which enables these germ-cells to develop into organisms similar to the parent—similar also in their ability to produce in their turn, germ-cells containing the same type of information. Although no clear-cut proof is presented, a good deal of weighty evidence is adduced² to show ‘that the structure of a butterfly, a snake, a tree, or a bird cannot be deduced mathematically from some relatively compact body of basic data stored in the chromosomes’; the ‘maintenance of information is ... not adequately described in terms of the mechanistic approximation’. The present writer has also been baffled by the miracle that there are organisms—that is, from the point of view of the physical scientist, structures—which, if brought into contact with certain nutrient materials, multiply, that is, produce further structures identical with themselves. He felt that it is, according to the known laws of physics, infinitely unlikely that structures of this nature exist and the present article is a report on the considerations and calculations which he undertook in this connection.³ Actually, the point of view is somewhat different from Elsasser’s: Elsasser considers the way in which the information necessary to develop the adult specimen is stored in the germ-cells and shows that the germ-cells do not have properties which the physicist would expect to be suitable for storing large amounts of information. We shall be concerned, on the other hand, with what appears to be a miracle from the point of view of the physicist: that there are structures which produce further identical structures.⁴