"It is no accident that Cartesian rationalism was completely blind to the forces of historical evolution. And what it applied to the past it proclaimed as programme for the future: that man in the full knowledge of what he was doing should deliberately create such a civilization and social order as the process of his reason enabled him to design. Rationalism in this sense is the doctrine which assumes that all institutions which benefit humanity have in the past and ought in the future to be invented in clear awareness of the desirable effects that they produce; that they are to be approved and respected only to the extent that we can show that the particular effects they will produce in any given situation are preferable to the effects another arrangement would produce; that we have it in our power so to shape our institutions that of all possible sets of results that which we prefer to all others will be realized; and that our reason should never resort to automatic or mechanical devices when conscious consideration of all factors would make preferable an outcome different from that of the spontaneous process. It is from this kind of social rationalism or constructivism that all modern socialism, planning and totalitarianism derives."