We learn more when we are compelled to invent.

Scientific knowledge is in perpetual evolution; it finds itself changed from one day to the next.

I could not think without writing.

Play is the work of childhood.

What is desired is that the teacher ceased being a lecturer, satisfied with transmitting ready-made solutions. His role should rather be that of a mentor stimulating initiative and research.

The more the schemata are differentiated, the smaller the gap between the new and the familiar becomes, so that novelty, instead of constituting an annoyance avoided by the subject, becomes a problem and invites searching.

What we see changes what we know. What we know changes what we see.