^'l' 



56 THE CASE AGAINST EVOLUTION 



periment, and so a factual proof is out of the question. Man> 

 the late-comer, not having been present at the birth of organic 

 forms, can give no reliable testimony regarding their parent- 

 age. In like manner, no a priori proof from the process of 

 inheritance is available, because heredity, as revealed to us by 

 the experimental science of Genetics, can account for specific 

 resemblances only, and cannot be invoked, at present, as an 

 empirically tested explanation for generic, ordinal, or phyletic 

 resemblances. It has still to be demonstrated experimentally 

 that the hereditary process is transcendental to limits imposed 

 by specific differentiation. There remains, however, the a pos- 

 teriori argument, which interprets homology and adaptation 

 as univocal effects ascribable to no other agency than the dual 

 process of inheritance and variation. What are we to think 

 of this argument? Does it generate certainty in the mind, 

 or merely probability? 



A moment's reflection will bring to light the preliminary 

 flaw of incomplete enumeration of possibilities. To suppose 

 that inheritance alone can account for structural resemblance 

 is an unwarranted assumption. Without a doubt, there are 

 other similifying influences at work in Nature besides inherit- 

 ance. True, inheritance is one possible explanation of the 

 similarity of organisms, but it is not the only one. Even 

 among the chemical elements of inorganic nature we find 

 analogous uniformities or ''family traits," which, in the absence 

 of any reproductive process whatever, we cannot possibly at- 

 tribute to inheritance. Mendeleeff's discovery of the perio- 

 dicity of the elements, arranged in the order of their atomic 

 weights, is well-known. At each interval of an octave, a suc- 

 cession of chemical types, similar to those of the preceding 

 octave, recur. Hence elements appearing in the same vertical 

 column of the Periodic Table have many properties in com- 

 mon and exhibit what may be called a family resemblance. 

 Now, we have in the process of atomic disintegration, as ob- 

 served in radioactive elements and interpreted by the electronic 

 theory of atomic structure, a reasonably satisfactory basis 



