I

Mere observation of the natural world, varied, fascinating, inexhaustible as it is, affords only the material for science. Observed facts must be built up, woven together, ordered, arranged, systematized into conclusions and theories by reflection and reason, if they are to have full bearing on life and the universe. Knowledge is the accumulation of facts. Wisdom is the establishment of relations. And just because the latter process is delicate and perilous, it is all the more delightful. The lofty scorn of the true philosopher for mere perception is well shown in Royer Collard’s remark: ‘There is nothing so despicable as a fact.’ Which does not prevent philosophers or any one else from making facts the essential basis of all discussion of relations. Darwin’s own comments on the general connection between the two are always interesting: ‘I have an old belief that a good observer really means a good theorist,’[432] and again: ‘About thirty years ago there was much talk that geologists ought only to observe and not theorize; and I well remember some one saying that at this rate a man might as well go into a gravel-pit and count the pebbles and describe the colors. How odd it is that any one should not see that all observation must be for or against some view if it is to be of any service.’[433]

It is supposed to be one of the chief functions of education to develop this faculty of relating facts to each other and to train and strengthen the reasoning powers. Darwin did not feel that education did much for him in this line, at any rate in the scientific directions which were of especial interest to him. He believed that his academic discipline was largely wasted. Making Latin verses did not appeal. More general lines of current information attracted him very little, and he seemed at times oddly ignorant of what the ordinary educated man is expected to know. Thus his son records that he once asked Hooker where ‘this place Wien is where they publish so many books.’[434] He read vastly in all that concerned his own work, but that very fact prevented his keeping up with daily interests that were remote from it. His own comment on his university experience is bitter: ‘During the three years which I spent at Cambridge my time was wasted, as far as the academical studies were concerned, as completely as at Edinburgh and at school.’[435] And he believed that he had learned everything that to him was worth learning pretty much by his own efforts: ‘I consider that all I have learnt of any value has been self-taught.’[436]

DOWN HOUSE FROM THE GARDEN

With this sort of discipline behind him, it is of great interest to examine his general attitude toward the connection of reasoning and fact. To some of us the controversy between induction and deduction has always seemed rather profitless. The Baconian insistence upon the absolute necessity of fact as the basis of all solid theory is of course indisputably just. But to talk of proceeding from abstract theory to the investigation of fact seems as barren as to wander aimlessly in unassorted realms of fact without the assistance of theory. It is comforting, therefore, to find so clear and systematic a thinker as Huxley unwilling to identify his processes with either complete induction or deduction: ‘Those who refuse to go beyond fact rarely get as far as fact; and any one who has studied the history of science knows that almost every great step therein has been made by the “anticipation of nature,” that is, by the invention of hypotheses which, though verifiable, often had very little foundation to start with; and not unfrequently, in spite of a long career of usefulness, turned out to be wholly erroneous in the long run.’[437]

Now Darwin obviously finds himself in precisely the uncertainty between inductive and deductive methods that Huxley here indicates. His instincts were naturally hostile to abstract theory, which used facts as playthings to substantiate soaring conjecture. He says in regard to one scientific author: ‘I am not convinced, partly I think owing to the deductive cast of much of his reasoning; and I know not why, but I never feel convinced by deduction, even in the case of H. Spencer’s writings.’[438] And he speaks even more specifically concerning Spencer himself: ‘I always feel a malicious pleasure when a priori conclusions are knocked on the head; and therefore I felt somewhat like a devil when I read your remarks on Herbert Spencer.’[439] Early and late he emphasized that ‘no one has a right to speculate without distinct facts.’[440] Yet at the same time he urges and reiterates that the mere collection of facts, without some basis of theory for guidance and elucidation, is foolish and profitless: ‘I am a firm believer that without speculation there is no good and original observation.’[441]

The truth is, the importance of imaginative power in the equipment of a great scientist is often underestimated. Exact and watchful vision is the first necessity; but it does not go far, or not farthest, except as it has behind it the thoughts that wander through eternity, the vast and questing genius that is perpetually on the lookout for causes and explanations and is eager to evolve theory from the sure and substantial but inanimate basis of fact. Even Thoreau almost deplores his intense preoccupation with the fascinating business of observing: ‘Man cannot afford to be a naturalist, to look at Nature directly, but only with the side of his eye. He must look through and beyond her. To look at her is fatal as to look at the head of Medusa. It turns the man of science to stone. I feel that I am dissipated by so many observations.... I have almost a slight, dry headache as the result of all this observing.’[442] Theory, speculation, must be perpetually checked and restrained by the precision of systematic logic, but the accurate eye and the careful finger need to be supplemented by the eternally active mind.

As to the activity of Darwin’s mind there can be no question whatever. He not only saw, but he thought incessantly. If you compare the Beagle Journal with the Journal of Thoreau, you see at once how much more quick and ready the English naturalist is with speculation and conjecture. The smallest fact is apt to set him off on a train of theory, where Thoreau simply records, or possibly compares, and passes on. How significant is the brief comment of Asa Gray, in regard to some botanical point which as a specialist in that line he should have been the first to develop: ‘That is real Darwin. I just wonder you and I never thought of it. But he did.’[443] And he not only thought himself, he had the rarer and more valuable faculty of making others think. His mind was so intense and so magnetic in its constant activity that all those who came into contact with it were impelled and fired to work double on speculation of their own. ‘You stimulate my mind,’ says Gray again, ‘far more than any one else, except, perhaps Hooker.’[444]

On this point of intellectual fertility, as on his other scientific qualifications, it is most interesting to hear Darwin himself. The mental activity was present early and late, and it does not appear that the exuberance of youth especially emphasized it or that it tended to increase with the later desire to develop and elaborate his special theories. He himself says in the Autobiographical sketch: ‘I am not conscious of any change in my mind during the last thirty years, excepting in one point: ... I think that I have become a little more skillful in guessing right explanations and in devising experimental tests; but this may probably be the result of mere practice, and of a larger store of knowledge.’[445]

The quick intelligence was always working, sometimes wearily, sometimes eagerly, but working, unless absolute physical prostration forbade. When he is too exhausted, he complains: ‘Facts compel me to conclude that my brain was never formed for much thinking.’[446] But if so, he certainly lived contrary to his nature. He tells us that he cannot resist forming hypotheses on every subject.[447] Sometimes he bewails the tendency, realizing its drawbacks and dangers. Sometimes he gives way to it, recognizing its charm: ‘It is delightful to have many points fermenting in one’s brain.’[448] Speculation is fascinating. Theory gives form and texture to the fleeting drift and confusion of fact. Yet even when one indulges with most enthusiasm, a touch of humor shows that the satisfaction must be tempered with a certain lack of entire confidence: ‘That is a splendid fact about the white moths; it warms one’s very blood to see a theory thus almost proved to be true.’[449]

For the wonder and the interest of Darwin is, that, with such an eager and perpetual bent toward theorizing, he could keep the bent so fully under control. As Karl Pearson puts it, generally: ‘Hundreds of men have allowed their imagination to solve the universe, but the men who have contributed to our real understanding of natural phenomena have been those who were unstinted in their application of criticism to the product of their imaginations.’[450] Surely no man applied such criticism more carefully, more conscientiously, more constantly than Darwin. He analyzes his own position and sees the dangers of it: ‘Living so solitary as I do, one gets to think in a silly manner of one’s own work.’[451] He sees constantly how theory interferes and warps the judgment: ‘I have not a doubt that before many months are over I shall be longing for the most dishonest species as being more honest than the honestest theories.’[452] The possibility of error haunts him, torments him, and he knows well how apt his own speculative disposition is to mislead: ‘What you hint at generally is very, very true: that my work will be grievously hypothetical, and large parts by no means worthy of being called induction, my commonest error being probably induction from too few facts.’[453] As a consequence he was ever on his guard against being led astray. The tempting little demon of hypothesis might be luring round the corner: ‘It is as difficult not to form some opinion as it is to form a correct judgment.’[454] But whatever opinion was formed must be corrected, must be adjusted, must be tested, by the cold and rigid measure of fact. As he says himself, ‘I have steadily endeavored to keep my mind free so as to give up any hypothesis, however much beloved (and I cannot resist forming one on every subject), as soon as the facts are shown to be opposed to it.’[455] And one who knew him well and had studied him carefully says the same thing with equal emphasis: ‘His long experience had given him a kind of instinctive insight into the method of attack of any biological problem, however unfamiliar to him, while he rigidly controlled the fertility of his mind in hypothetical explanations by the no less fertility of ingeniously devised experiment.’[456]

In regard to this matter of speculative freedom and the tendency to let imagination run wild, it is interesting to watch Darwin’s comments on the general methods of others. The excess of abstinence he indeed deplores, recognizing that a man’s extreme caution may prevent him from theorizing enough: ‘How many astronomers have labored their whole lives on observations, and have not drawn a single conclusion.’[457] But the danger on the other side is so great and so ruinous that it cannot be enough insisted on, and indeed at times it makes all generalization suspicious and almost a thing to be eschewed: ‘I look at a strong tendency to generalize as an entire evil.’[458] At any rate, the theorist must never forget the subjective element, that his preconceptions and prejudices are apt to warp his judgment and distort his vision, till the keenest of observers and the sanest of thinkers may go astray: ‘the firmest conviction of the truth of a doctrine by its author seems, alas, not to be the slightest guarantee of truth.’[459]

The profit and the lesson of all which must be constantly borne home to oneself: ‘When I think of the many cases of men who have studied one subject for years, and have persuaded themselves of the truth of the foolishest doctrines, I feel sometimes a little frightened, whether I may not be one of these monomaniacs.’[460]

To appreciate fully Darwin’s combination of mental activity and fertility with moderation and restraint, it is well to place him between two extreme types of thinkers. On the one hand, there is the born essential reasoner, and logician, Spinoza, for instance, or Hegel, or Darwin’s own contemporary, Spencer, the man who to a greater or less extent takes fact for his foundation, but who by nature and temperament delights to weave an elaborate web of logical theory, rigid and perfect in its appearance of systematic deduction, but too apt in the end to treat facts with indifference if not disrespect. I like especially in this regard to compare Darwin with Lucretius. The De Rerum Natura is one of the most striking, enthralling examples of what I should call passionate thinking. Theoretical problems take hold of Lucretius like the ecstasies of love. He tears and wrenches at the roots of thought, determined to make them yield to the delving vigor of his eager search. Now Darwin has a broad and constant curiosity, his interest may well be called enthusiasm, and he himself uses the term passion for it: ‘Hence it has come to be a passion with me to try to connect all such facts by some sort of hypothesis.’[461] Yet in no phase of his nature should I be inclined ever to employ the general word, ‘passion,’ and it seems to me that every page of Lucretius is stamped with a devouring ardor different from anything Darwin knew.

On the other hand, over against these furious reasoners, I should set Darwin’s close contemporary, Sainte-Beuve, who, as I said in the previous chapter was, in some aspects, as admirable a representative of the scientific spirit as Darwin himself. The endless curiosity, the unlimited observation of fact, as embodied in the human subject, have never been more richly exemplified than in the great French critic. But Sainte-Beuve was no reasoner in the larger sense. He did not even avoid reasoning from mistrust: he had no taste for it, and when he dealt with it, it was always charily and with extreme reserve. He delighted to study and portray individuals and to allow those individuals, as it were, to classify themselves and so to point the way to general results.

Between these two extremes Darwin stands, as one who used reasoning to the fullest extent for the interpretation of fact, yet at the same time always stuck closely and rigidly to the fact itself, and would not allow it to be for an instant distorted by the reasoning process.