WCP4065

[1]

Frith Hill, Godalming

August 25th. 1886

My dear Newton¹,

I have not, I fear, explained so fully as I shall have done in my paper, what seems to me the fundamental difficulty in the views of Belt² & Romanes³, — which is, the complex relations involved in the needful variations. I quite agree that variations in the degree of fertility are likely to be quite as common as any other variations — that is that some individuals (♂. or ♀.) are likely to be more fertile, some less fertile than the average. [2] But this is nothing to the point. The required variation is, that an individual shall be less fertile with the bulk of its species & also, at the same time, more fertile with some few. Even this, I admit, may be tolerably common, — but then ^comes the ^real difficulty. — Let a. b. c. &c. be such varieties, occurring here & there simultaneously in a species — each infertile with the bulk of the species but very fertile with some few — which I have called its "complements". Why should the "complements" of a., be also the complement of b., and of c.? This seems to me so improbable [3] that the contrary is almost certain, that is, that a., b., c., &c. &c. will each have a different set of "complements"; and if so, it is almost impossible that each should meet and pair with its own complements unless in each case these complements constituted a considerable proportion of the whole species. Even then each one of these initial var[ieties] — a. b. c. &c; would be practically a distinct variety, & there is no reason to suppose that their descendants would be fertile with each other, [4] and if not there could be no advantage in there being many such variations, since each one would not be benefited by the existence of the others.

This is the point which Romanes has totally overlooked. It is, at any rate, the difficulty, yet I do not think he once refers to it in his whole paper!

He throughout leads the reader to suppose that his Phys[ical] var[ieties] are simple varieties, and varieties with complex relations⁴

My paper was primarily intended to disprove Romanes' statement that Nat[ural] Select[ion] is not a theory of the origin of species! and as I particularly wished to appear on Sept. 1st for the Brit[ish] Ass[ociation] I did not give quite space enough to the letter past.

Yours faithfully | Alfred R. Wallace [signature]

Prof. A. Newton