What has to be accepted, the given, is – so one could say – forms of life.

The statement ‘Corgis and basset hounds have ears of different lengths’ is meaningful and useful when it comes to recognizing these life forms, but is uninformative about their hearing ability. ‘Sharks have longer flippers than whales’ also has some kind of meaning, even if the life forms belong to different families, but fails to indicate which one is the better swimmer. However, ‘squid have more fingers than humans’ is a somewhat misleading statement (squid hardly ever wear gloves, even in cold seas), and it is difficult to find a context where such a statement would be useful. The usefulness of a statement about one form of life using descriptive units relevant to another form of life depends on how members of these families resemble one another, and such a statement is not informative about the consequences of the described difference.