It is in Man's power to treat himself as a mere "natural object" and his own judgements of value as raw material for scientific manipulation to alter at will. The objection to his doing so does not lie in the fact that this point of view (like one's first day in a dissecting room) is painful and shocking till we grow used to it. The pain and the shock are at most a warning and a symptom. The real objection is that if man chooses to treat himself as raw material, raw material he will be: not raw material to be manipulated, as he fondly imagined, by himself, but by mere appetite, that is, mere Nature, in the person of his dehumanized Conditioners.

We have been trying, like Lear, to have it both ways: to lay down our human prerogative and yet at the same time to retain it. It is impossible. Either we are rational spirit obliged for ever to obey the absolute values of the Tao or else we are mere nature to be kneaded and cut into new shapes for the pleasures of masters who must, by hypothesis, have no motive but their own "natural" impulses. Only the Tao provides a common human law of action which can overarch rulers and ruled alike. A dogmatic belief in objective value is necessary to the very idea of a rule which is not tyranny or an obedience which is not slavery.

--- C. S. Lewis, The Abolition of Man