Eugenics as a Creed and the Last Decade of Galton's Life 309
his biographer. In 1907 Galton, though he still had cause for anxiety, recovered something of his usual mental activity and. hopefulness. He had been asked and with some hesitation had consented to give the Herbert Spencer Lecture at Oxford on June 5th meanwhile his biographer had been invited to give the Boyle Lecture on May 17th, and in accepting had taken for his topic : " The Scope and Importance to the State of the Science of National Eugenics." On the other hand, Galton chose as his subject-matter: "Probability, the Foundation of Eugenics*," although the most interesting part of his lecture strayed somewhat from that topic. By the title Galton chose for his lecture he definitely gave forth as his opinion that his new science of Eugenics ought to be based on the actuarial treatment of man. For him the selective mating-rate, the selective birth-rate, the selective death-rate, and heredity in man were fundamentally mass-problems, to be solved statistically, by actuarial methods; shortly, Eugenics was a branch, the most important branch, of Biometry. For evolution the important matter is the changes that are taking place in the type or average of a species, and the variations that render these changes possible. -We may never be able to predict what the individual child C of a given A and B will be like, but we can state the probability that he will be so and so ; in other words, we know the average' distribution of character in the children of all parents like A and B. If A and B both come of stock tainted with insanity, we can predict with considerable accuracy the- percentage of their offspring which will be insane or transmit insanity. It is no argument against the eugenic principle-that A and B ought not to have had children-to tell us that their particular child, C, is sane-he may be indeed a genius. The aim of Eugenics is to improve the race as a whole-to raise our nation above its present low level-not to breed one sane man at the cost of producing one or more bred insane. No-farmer would be content with his flock, if with every white lamb, however fine its wool, he added at the same time a black sheep to his flock ! I think _this is the meaning of Galton's statement that probability is the foundation of Eugenics, and of his opinion expressed in his letter to Bateson that " an exact knowledge of the laws of heredity " would scarcely help us in the problems of Eugenics t.
A few letters here may throw light on the trend of events.
March 2, 1907.
MY DEAR FRANCIS GALTON, Just a line to say that I have been asked to give the Boyle Lecture at Oxford this year (May 17th) and have settled to take " The Scope and Importance to the State of the Science of National Eugenics " for my topic. I expect my views will not wholly satisfy you, but they may help to push forward the whole movement and lead some of the younger Oxford men to think over and possibly take up the subject. If any ideas occur to you before Easter I should be glad of jottings or of suggestions for lines of thought. My idea
is to indicate what we know already, what again we need to find out, and, how much all these
* Oxford, at the Clarendon Press, 1907.
f See p. 221 above. It is, perhaps, needless to remark that-with all the thousands of pounds and of pages°devoted to genetic research during the last 25 years we seem to-day scarcely nearer the exact knowledge of the laws of heredity; the further we advance the' more complex does the problem show itself.