ABSTRACT
Symmetry constitutes an apparently complex correspondence. On the one hand, it is a variety of isomorphism; on the other, it involves a reversal of directions or of order starting from some point or axis such that the symmetrical of ABC but oriented toward the right or toward the top will still be ABC but ordered toward the left or toward the bottom. This reversal can present problems when it has to be constructed (especially in the situation studied in this chapter). From the figurative point of view, however, it corresponds to a perceptual “good form,” so that figural symmetries play a very precocious and general role in young children. This is the case not only in their spontaneous drawings but also when one asks them to put some little unequal sticks “in good order.” In this instance, instead of seriating them, they arrange them symmetrically. Similarly, in order to balance a scale, they resort to spatial symmetries well before they dream of equalizing weights, and so forth.
