SIR W.T. THISELTON-DYER TO A.R. WALLACE
The Ferns, Witcombe, Gloucester. February 12, 1911.
Dear Mr. Wallace,— ... You must let me correct you on one technical point in your letter. It is no longer possible to say that chemists effect the synthesis of organic products "by the use of other organic substances." From what has been already effected, it cannot be doubted that eventually every organic substance will be built up from [pg 096] "the few simple elements available in air, earth and water." I think you may take it from me that this does not admit of dispute....
At any rate we are in agreement as to Natural Selection being capable of explaining evolution "from am[oe]ba to man."
It is generally admitted that that is a mechanical or scientific explanation. That is to say, it invokes nothing but intelligible actions and causes.
De Vries, however, asserts that the Darwinian theory is not scientific at all, and that is of course a position he has a right to take up.
But if we admit that it is scientific, then we are precluded from admitting a "directive power."
This was von Baer's position, also that of Kant and of Weismann.
But von Baer remarks that the naturalist is not precluded from asking "whether the totality of details leads him to a general and final basis of intentional design." I have no objection to this, and offer it as an olive-branch which you can throw to your howling and sneering critics.