A large body of facts and an adequate propor­tion of reasoning have been brought together in the preceding chapters. As far as I understand the proceedings in a court of law, the business of arriving at results or, as they are there called, verdicts, consists in collecting as many as possible of the facts which bear on the case, these are sifted and verified, or the reverse, a certain reasoning on them is carried on; on this the verdict rests. This case before the court is of a civil, not a criminal nature, and it is a claim made to a certain derelict property, that is to say, the honour of forming patterns on the hair of animals, claimed by Use and Habit. The facts concerned have never been disputed, possibly because they were not thought worth the trouble, but they have the singular merit of being open to almost any educated person for confirma­tion or correc­tion, and the reasoning is certainly not profound, though I think it is cogent. In seeking a result in such a cause, or verdict, one claimant might content himself with an arrest of judgment, another that judgment should go by default, and a third would claim proof. It is with the last I desire to stand.

In one word the claim is that of causation.

Now no one can deny that between the groups of phenomena, habits and hair-patterns there is an evident relation; but the question may still arise, “What is the link between them?” I have just said that the facts are unquestioned; substantially they are unquestionable, and they are open to the charge that they belong to the dust-heaps of science, that they are, biologically speaking, such as used to engage the attention of Nicodemus Boffin. Perhaps they are. Of course if they were just collected haphazard and treated like a big collec­tion of little shells in a cabinet, without reference to their natural order, they would possess no evidential value even if they were pretty, for so long as a natural fact remains without its suited interpreta­tion, so long it belongs not to science. Hear Jevons: “Whatever is, is, and no natural fact is unworthy of study for the purpose of its interpreta­tion.”60 Hear also Sir E. Ray Lankester: “That only is entitled to the name of science which can be described as knowledge of causes or knowledge of the order of Nature.”61 Fortified by the authority of a great logician and a great biologist I proceed to claim proof of causation. The stages of the case may be summed up as follows:

1. It has been shown that during the lifetime of an individual, muscular action can change the direction of the hair. Chapter VIII.

2. Undesigned experiment has shown that changes in the direction of the hair, mechanically produced in the individual, are sometimes transmitted to the descendants. Chapter XV.

3. In all the selected examples adequate and ascertainable causes have been demonstrated.

4. The changes of hair described, with hardly an exception, cannot be conceived as resulting from the factors of organic evolution—heredity, variation, adapta­tion and selection—indeed no serious attempt has been made to connect them in any way with utility.

Causation.

For my sins, the most obvious of which is that I made an unfortunate choice of my first birthday, I had to learn up the dreary pages of Mill’s Logic and those of other philosophers, for the pleasure of taking a medical degree, and was reduced to that orthodox state of mind in which one was forbidden to suppose that, in the world around where common men and women, every day and all day, are tracing causes for the occurrences they see on every hand, there was anything at work which could be truly called a cause. It was but natural to fall into the nihilism of the Mill and Karl Pearson school. Having neither the knowledge nor the hardihood to discern that their bewildering notions of causation could be gainsaid, I had to remain submissive and as much contented as possible with their views of an elusive subject. This state of passive resistance was not relieved until I had the great advantage of reading a valuable book by the late Dr. Mercier on Causation, which seems to have let some fresh air into the musty doctrines of the orthodox and autocratic philosophers. No one who has read this work can doubt that after all there is such a process as causation, and that to find a cause for events is not merely a pursuit of the vulgar, but a duty of scientific persons.

Mill appears to have given eighteen different accounts of causation and to have contradicted himself over and over again in his works dealing with this puzzle, devised mainly by Hume and himself; and his successors, such as Dr. Mc’Taggart, the Hon. Bertrand Russell of “Dog Fight” fame, Mr. Welton and Prof. Karl Pearson, have only got as far as to reduce the number of his definitions and put his views into more modern, but equally misleading terms. Without any disparagement of their other claims to respect and admira­tion, one may venture to throw overboard this school of philosophers when considering causation, and one may walk and talk in a clearer atmosphere.

The subjects here considered are cause, effect, result, reason, evidence and proof, and all can be seen to enter into my small thesis. They may then be defined, according to Dr. Mercier, as follows:—

1. A cause is an action, or cessation of action, connected with a sequent change or accompanying unchange, in the thing acted on, or more shortly for my purpose a cause is an action upon a thing.

2. An effect is a change connected with a preceding action.

3. In reference to causation a reason means the cause of an unchange.

4. A result is the changed state that is left when an effect has been produced.

5. Evidence is of three kinds: evidence of sense, evidence of reason and evidence of hearsay.

6. Proof is evidence inconsistent with an alternative to the assertion.

I turn now to the aid given to the case before the jury, and must show how Dr. Mercier’s definitions establish it.

The cause of the changes described is the action of certain new habits on a living growing structure of the mammalian body.

The effect is the change connected with the preceding change of habit.

The result is the changed direction of hair, in other words, new patterns, left when the new habits have been produced, and have been long enough in operation.

The reason for the unchanges observed in many instances is the primitive force of the normal direction of growth of the hair.

The proof of the thesis is that the changes described in the hair—the evidence—is inconsistent with an alternative assertion.

To Some Critics.

It may save time and trouble if replies are given in anticipa­tion to certain classes of critics. I refer of course to those who are well-informed in their branch of knowledge.

To those of high authority and learning, those who ride on white asses and that sit in judgment, who may seek to throw the case into chancery, saying, “This will never do, it contradicts current biological opinion.” I can only meekly reply that current or orthodox opinion is frequently wrong, or (shall I say) seldom right, and that the history of human thought is strewn with examples which may justify my impertinent reply.

To another who says, “I daresay you are right in your claim, but there are too many metaphors,” I would suggest that, so long as metaphors are not used as arguments, the more metaphors—within limits—the clearer the meaning of the statement.

To him who grudgingly allows, “I think you have proved your case—but what does it prove?” I reply that it proves what it set out to prove, no more and no less, and it is an integral part of proof of a larger claim. And if he further grumble that these matters have no interest for him, one may ask him to live and let live. “What have I now done in comparison of you, is not the gleaning of your grapes of great Ephraim better than the vintage of this little Abiezer?”

To the man who reads the preface and the headings of the chapters, glances at the illustrations, detects one split infinitive, two misspellings and three errors of punctua­tion, goes home to tea and writes his opinion—it may suffice to remind him of “that curious mental state which looks past problems without seeing them.”

I will conclude this section with a parable.

In the year 1788 Arthur Young in his travels through France visited the desolate region of the Landes. “Wastes, wastes, wastes!” was his lament over neglected Brittany, and no less could he say of the Landes, at that time a miserable tract of low ground, bordering the Bay of Biscay. Plantations, the sinking of wells, drainage and irriga­tion began to fix the unstable sands, making fruitful the marsh, creating a healthful climate and a fertile soil. Early in the 19th century the land here was sold au son de la voix, that is to say, the accepted standard of measurement was the compass of the human lungs. The stretch of ground reached by a man’s voice sold for a few francs. Crops replaced the scanty herbage of the salt marsh, and a familiar characteristic of the landscape, the shepherd on stilts, was seen no more. Six hundred thousand hectares of Landes planted with sea pines produced resin to the annual value of fifteen million francs, and through these trees also was achieved a climatic revolu­tion, and it is this district which is now a department of a great and well-ordered State.62