for example, to see whether in the developing subject, i.e. the child, integers are directly constructed starting from class logic by biunivocal corr… - Jean Piaget

In certain circumstances where he experiments in new types of conduct by cooperating with his equals, the child is already an adult. There is an adult in every child and a child in every adult. … There exist in the child certain attitudes and beliefs which intellectual development will more and more tend to eliminate: there are others which will acquire more and more importance. The later are not derived from the former but are partly antagonistic to them.

The majority of parents are poor psychologists and give their children the most questionable moral trainings. It is perhaps in this domain that one realized most how keenly how immoral it can be to believe too much in morality, and how much more precious is a little humanity than all the rules in the world. Thus the adult leads the child to the notion of objective responsibility, and consolidates in consequence a tendency that is already natural to the spontaneous mentality of little children.

Logic is the mirror of thought, and not vice versa;in classes, relations et nombres; essai sur les groupements de logistique et la réversibilitié de lq pensée