« Celui qui peut, agit. Celui qui ne peut pas, enseigne. »

George Bernard Shaw – Maximes pour révolutionnaires (1903)

« He who can, does. He who cannot, teaches.

A learned man is an idler who kills time with study. Beware of his false knowledge: it is more dangerous than ignorance.

Activity is the only road to knowledge.

No man can be a pure specialist without being in the strict sense an idiot. »