1. The fact that success, even with the most richly-endowed natures, is only possible through specialism.
2. The imperfections and uncertainties of memory.
3. The exceedingly narrow limitations of the senses.
4. The fact that the best results of cerebral activity are largely involuntary, if not unconscious.
Specialism is not peculiar, as some would believe, to modern science or recent civilization; all the famous Greeks were specialists: one could not conceive of a Socrates, Homer, Phidias, Pericles, Demosthenes, and Sophocles, combined in a single individual. Although poetry and philosophy, being nearly allied, have been the twin products of one superlatively endowed intellect—although Goethe has demonstrated the possibility of uniting the genius of song with the genius of speculative science—yet no human being as yet proved himself at once great in poetry and mathematics. The combination of a Newton and Milton seems impossible; a conclusive and crushing deductive argument against the theory of the Baconian origin of Shakespeare's plays is, that no single brain could have produced the "Novum Organum" and "Hamlet."
In the present century, science has become so specialized that all the advances are made by specialists in comparatively restricted fields, by men whose entire energies are concentrated for a lifetime in some single path of research beyond which they never wander, and in which alone they are accepted as guides. So universal is this law of specialism that the instincts of men regard with suspicion any one who attempts to become an authority on more than one branch of science, while literature is so split up into divisions and subdivisions that eminence in all is unattainable. The lopping away of all superfluous branches, that bearing boughs may live, is carried to such an extreme that only one branch remains, and through this the whole cerebral force circulates. The human mind is like a stream which carries along the same amount of water, whether it flows through one channel or many. In spite of all the criticisms of specialism and specialists, the work of specialization has gone on, and in obedience to the law of evolution must yet go on; specialists are our sole authorities, even among those who despise them:
in certain grooves, as it were, the result is more rapid succession. Thus one student was able to think in a minute of thirty different kinds of actions, forty-six animals, fifty places or fifty persons. I can myself think, without much effort, of thirty-two animals or forty places or persons, in a minute. Even in these cases, however, it will be found that the rapidity greatly depends upon the degree in which the objects have been associated. When thoughts have been very closely and frequently linked together, the number of which may be compressed within a minute is much greater. I find that I can count about ninety-six in half a minute, which, without allowing for the two places of figures, gives one hundred and ninety-two thoughts per minute. I can think of every letter in the alphabet in five seconds at most, which is at the rate of more than three hundred per minute. Finally, by counting the first ten numbers over and over again, I have compressed nearly four hundred changes of idea within the minute.' "