He who believes that some ancient form was transformed suddenly through an internal force or tendency into, for instance, one furnished with wings, will be almost compelled to assume, in opposition to all analogy, that many individuals varied simultaneously.
Antzinako formaren bat barne-indar edo joeraren baten bidez, adibidez, hegoz hornituriko izaki bilakatu zela sinesten duena, ia beharturik aurkituko da, analogia ororen kontra, aldi berean banako asko aldatu zirela onartzera.