Born in Vienna, Austria, in 1893, Paul Diel is orphan at the age of 14, and completes high-school thanks to the material support of a benefactor. He then undertakes self teaching in philosophy. Inspired notably by Platon, Kant and Spinoza, but also by Freud’s, Adler’s and Jung’s discoveries, he deepens his own psychological research by establishing the bases of an introspective method first experimented on himself.
Firstly a psychologist in the central hospital of Vienna, he escapes to France after anschluss, works in Saint-Anne’s psychiatric hospital in Paris until world war II, during which he had to suffer the hard life of french foreign refugees camps. Then, in 1945, backed by Albert Einstein, with whom he sustained a correpondance over many years, he joins CNRS, where he will work as children psychotherapist in Henri Wallon’s laboratory.

Until his death, occurred in 1972, Diel endlessly continued his task of researcher and psychoanalyst, training a group of students and publishing new books on various subjects (education, symbolism, evolution, etc…) but all of them linked by the same usage of his introspective method.