Bacon had. justly reproached the physicians of his time for their neglect to make records of the cases of their patients.... Sydenham.... by his bedside study again brought it into favor." And finally, "he found English medicine reduced to the lowest state of empiricism—he raised it once more to the dignity of a science of observation."[1]
The disposition in which Locke entered on his inquiry was certainly "to exclude prevailing theories," for he has himself recorded that his Essay originated in a conviction that, before advancing to abstruse problems, "it was necessary to examine our own abilities, and see what objects our understandings were or were not fitted to deal with." His method of induction was truly Baconian: he approached the subject without any clear design, proceeded without a plan, and attained such results as can be so reached. But the "laws ruling the" formation of ideas were elucidated, and mixed and simple modes "described with an accuracy" and in one or two cases with "a graphic coloring" which have not been greatly surpassed. The philosophy of the mind he found an untrodden jungle, with a few bridle-paths in the directions marked "Sense," "Appetite," etc.; he cut a highway through the part where the bush was thickest—the region of ideas. The a priori method was in favor, and "bedside study" of the human patient out of fashion; the a priori method he did not indeed kill, but he left it to die a lingering death; and though to Hobbes belongs the honor of introducing the experimental method into Psychology, it may be truly said of Locke that he "raised it to the dignity of a science of observation." And just as Sydenham, follower of Hippocrates as he was, attributed a number of diseases to morbid fermentation in the humors, so Locke, in spite of his antischolasticism, could still assign the motion of the "animal spirits" as a "natural cause" of certain ideas.[2] The defects and the merits, in truth, of Locke's procedure were equally those of the physical science of the age. The patient observation of which Sydenham set the example gave rise to the first discriminative account—we can hardly call it analysis—of the proximate origin and more obvious constituents of our ideas. To the same causes and doubtless also to the impulse of conquest in unexplored regions which the post-mediæval world owed to Bacon, we may ascribe it that Locke's "Essay," as he named it, "inquiry," as he described it, was the first comprehensive survey of mental phenomena; while the small part which hypothesis and theory play in his investigation, his incomplete statement of mental causation of all kinds, his bare discovery of association as producing a few obvious compounds, were clearly due to the unspeculative character of the contemporary science to the influence of which he was most exposed.
Berkeley's most notable contribution to philosophy belongs rather to the metaphysics, than to the psychology, of sensation; and his less
