A presumption of equality may be contrary to present fact, and yet not contrary to a desideratum. We are not as a fact all equally fit to live, equally responsible, or equally deserving of the protection of the law: but it will hardly be doubted that it would be desirable if we were.
But further, the presumption of a desired condition is, in any group of plastic minds, a force tending to bring about the thing presumed, i. e., to create it. It aids a boy to reach maturity to treat him as if he were a little older than he is. A little older: for the presumption loses its effect if it is too wide of the actual fact. The fundamental presumptions of the law are justified on this basis and to this extent: if they are too wide of the truth to be creative, they are not justified.