This new philosophical psychology can in this respect be traced back to Maine de Biran, for even if in his time scientific psychology was unaware of … - Jean Piaget

Between the various types of rules which we shall give there will therefore be at once continuity of function and difference of structure. This renders arbitrary any attempt to cut mental reality up into stages. The matter is further complicated by the "Law of conscious realization" and the resulting time-lag. The appearance of a new type of rule on the practical plane does not necessarily mean that this rule will come into the subject's consciousness, for each mental operation has to be relearned on the different planes of action and of thought.

There are in existence two distinct ideas of justice. We say that an award is unjust when it penalizes the innocent, rewards the guilty, or when, in general, it fails to be meted out in exact proportion to the merit or guilt in question. On the other hand, we say that a division is unjust when it favors some at the expense of others. In this second adaptation of the term, the idea of justice implies only the idea of equality. In the first acceptation of the term, the notion of justice is inseparable from that of the reward and punishment, and is defined by the correlation between acts and their retribution.

For the fundamental fact of human psychology is that society, instead of remaining almost entirely inside the individual organism as in the case of animals prompted by their instincts, becomes crystallized almost entirely outside the individuals. In other words, social rules, as Durkheim has so powerfully shown, whether they be linguistic, moral, religious, or legal, etc., cannot be constituted, transmitted or preserved by means of an internal biological heredity, but only through the external pressure exercised by individuals upon each other.