Incidentally we have touched upon a most far-reaching problem: The alterability of human nature. Early reformers, following John Locke, were inclined to minimize the significance of native activities, and to emphasize the possibilities inherent in practice and habit-acquisition. There was a political slant to this denial of the native and a priori, this magnifying of the accomplishments of acquired experience. It held out a prospect of continuous development, of improvement without end. Thus writers like Helvetius made the idea of the complete malleability of a human nature which originally is wholly empty and passive, the basis for asserting the omnipotence of education to shape human society, and the ground of proclaiming the infinite perfectibility of mankind. Wary, experienced men of the world have always been sceptical of schemes of unlimited improvement. They tend to regard plans for social change with an eye of suspicion. They find in them evidences of the proneness of youth to illusion, or of incapacity on the part of those who have grown old to learn anything from experience. This type of conservative has thought to find in the doctrine of native instincts a scientific support for asserting the practical unalterability of human nature. Circumstances may change, but human nature remains from age to age the same. Heredity is more potent than environment, and human heredity is untouched by human intent. Effort for a serious alteration of human institutions is utopian. As things have been so they will be. The more they change the more they remain the same. Curiously enough both parties rest their case upon just the factor which when it is analyzed weakens their respective conclusions. That is to say, the radical reformer rests his contention in behalf of easy and rapid change upon the psychology of habits, of institutions in shaping raw nature, and the conservative grounds his counter-assertion upon the psychology of instincts. As matter of fact, it is precisely custom which has greatest inertia, which is least susceptible of alteration; while instincts are most readily modifiable through use, most subject to educative direction. The conservative who begs scientific support from the psychology of instincts is the victim of an outgrown psychology which derived its notion of instinct from an exaggeration of the fixity and certainty of the operation of instincts among the lower animals. He is a victim of a popular zoology of the bird, bee and beaver, which was largely framed to the greater glory of God. He is ignorant that instincts in the animals are less infallible and definite than is supposed, and also that the human being differs from the lower animals in precisely the fact that his native activities lack the complex ready-made organization of the animals' original abilities.