Louis Agassiz wrote:
…if species do not exist at all, as the supporters of the transmutation theory maintain, how can they vary? And if individuals alone exist, how can differences which may be observed among them prove the variability of species?
Darwin responded to Asa Gray:
I am surprised that Agassiz did not succeed in writing something better. How absurd that logical quibble — “if species do not exist how can they vary?” As if anyone doubted their temporary existence.
The irony is that science works by finding invariants — things that don’t change. If everything is always changing (and changing in ways that change), science is impossible.
There are many problems with the species concept but the main problem is that species are not even close to a concept of invariant/created kind. For human beings we cannot accept any speciation; there is only one kind. On the other extreme for microorganisms we can accept many speciations within a created kind. Other organisms are in between — it’s something like the more complex organisms are, the fewer species there can be.
A concept of created kinds is not like species because kinds are permanent, like chemical elements.
January 2014