Apostel was an advocate of interdisciplinary research and the bridging of the gap between exact science and humanities.

[citation needed] After the second World War he studied philosophy at the ULB in Brussels with philosopher of law and logician Chaïm Perelman.

The transdisciplinary research department Center Leo Apostel (CLEA) at the Vrije Universiteit Brussel was named after him.

[citation needed] In his book "Oorsprong" (Origin) from 2000 Apostel gives a metaphysical introduction about the beginning of man, life and the universe.

In this book he first outlines the term metaphysics, then presents an ontology, which results in his own consistent world view.