As closely connected with this general criticism of Locke's system, or rather as presenting the defects just criticised under another form, I may notice the tendency of the _Essay_ to bring into undue prominence the passive receptivities of the Mind, and to ignore its activity and spontaneity. The metaphor of the _tabula rasa_, the sheet of "white paper," once admitted, exercises a warping influence over the whole work. The author is so busied with the variety of impressions from without, that he seems sometimes almost to ignore the reaction of the mind from within. And yet this one-sideness of Locke's conception of mind may easily be exaggerated. "When the Understanding is once stored with simple ideas, it has the power to repeat, compare, and unite them, even to an almost infinite variety, and so can make at pleasure new complex ideas." (Bk. II., ch. ii., § 2.) Moreover, amongst the simple ideas themselves are the ideas of Reflection, "being such as the mind gets by reflecting on its own operations." The system, in fact, assumes an almost ceaseless activity of mind, after the simple ideas of sensation have once entered it. But where it fails is in not recognizing that mental reaction which is essential to the formation of even the simple ideas of sensation themselves, as well as that spontaneous activity of mind which often seems to assert itself independently of the application of any stimulus from without. Here again a more scientific psychology than was possible in Locke's day comes to our aid, and shows, as is done by Mr. Bain and other recent writers, that the nerves, stored with energy, often discharge themselves of their own accord, and that movement is at least as much an original factor in animal life as is sensation, while sometimes it even precedes it in time. Had the constant interaction of mental activity and mental receptivity, producing a compound in which it is often almost impossible to disentangle the elements, been duly recognized by Locke, it would certainly have made his philosophy less simple, but it would have made it more true to facts. Physiology, however, was in his days in far too backward a state itself to throw much light upon Psychology. And the reaction against the prevailing doctrine of Innate Ideas naturally led to a system in which the influences of external circumstances, of education and habit, were exaggerated at the expense of the native powers, or as they might more appropriately be called the inherited aptitudes, and the spontaneous activity of the mind. Here, tempting as it is to follow my author along the many tracks of psychological, metaphysical, and logical discussion which he always pursues with sagacity, candour, and good sense, if not always with the consistency and profundity which we should require from later writers, my criticism must necessarily end.