Chapter XII

a mere provisional statement from a popular and prejudiced point of view.

=Conclusion.=--When, then, we talk of 'psychology as a natural science,' we must not assume that that means a sort of psychology that stands at last on solid ground. It means just the reverse; it means a psychology

## particularly fragile, and into which the waters of metaphysical

criticism leak at every joint, a psychology all of whose elementary assumptions and data must be reconsidered in wider connections and translated into other terms. It is, in short, a phrase of diffidence, and not of arrogance; and it is indeed strange to hear people talk triumphantly of 'the New Psychology,' and write 'Histories of Psychology,' when into the real elements and forces which the word covers not the first glimpse of clear insight exists. A string of raw facts; a little gossip and wrangle about opinions; a little classification and generalization on the mere descriptive level; a strong prejudice that we _have_ states of mind, and that our brain conditions them: but not a single law in the sense in which physics shows us laws, not a single proposition from which any consequence can causally be deduced. We don't even know the terms between which the elementary laws would obtain if we had them (p. 464). This is no science, it is only the hope of a science. The matter of a science is with us. Something definite happens when to a certain brain-state a certain 'sciousness' corresponds. A genuine glimpse into what it is would be _the_ scientific achievement, before which all past achievements would pale. But at present psychology is in the condition of physics before Galileo and the laws of motion, of chemistry before Lavoisier and the notion that mass is preserved in all reactions. The Galileo and the Lavoisier of psychology will be famous men indeed when they come, as come they some day surely will, or past successes are no index to the future. When they do come, however, the necessities of the case will make them 'metaphysical.' Meanwhile the best way in which we can facilitate their advent is to understand how great is the darkness in which we grope, and never to forget that the natural-science assumptions with which we started are provisional and revisable things.

THE END.

INDEX.

Abstract ideas, 240, 25; characters, 353; propositions, 354

Abstraction, 251; see _Distraction_

_Accommodation_, of crystalline lens, 32; of ear, 49

Acquaintance, 14

Acquisitiveness, 407

## Action, what holds attention determines, 448

After-images, 43-5

AGASSIZ, 132

Alexia, 113

ALLEN, GRANT, 104

Alternating personality, 205 ff.

AMIDON, 132

Analysis, 56, 248, 251, 362

Anger, 374

Aphasia, 108, 113; loss of images in, 309

Apperception, 326

Aqueduct of Silvius, 80

Arachnoid membrane, 84

Arbor vitæ, 86

ARISTOTLE, 318

Articular sensibility, 74

Association,