ABSTRACT
We analyze, through writings of d’Alembert, the
complex relationships that mathematics, physics and metaphysics entertain with man’s faculties and their linguistic manifestations
and highlight critical issues and philosophical and epistemological
consistency, which we consider valid and actual. For the illuminist d’ Alembert
all good physical science is established and developed on a good philosophy and
vice versa, as any good philosophy must be consolidated
on a good metaphysics, to fertilize then good science. A well-structured science can then only be founded on a well-constructed language. Then the good
metaphysics is above all critical of abusive and badly constructed languages,
confused, quirky, nominalistic, empty, contradictory, when they hypostatize or
reify mere names (force, cause, infinitesimal,
infinite, axiom), they transform mere relations between simple physical
properties in physical entities (velocity, acceleration, differential) or
exchange names for questions about physical realities (the querelle about living forces), generic and
vague names (being, substance, idea) for metaphysical principles (Plato,
Aristotle, Scholastic).