Dietrich Tiedemann

Tiedemann's system was based on the metaphysics of Leibniz and the epistemology of Locke.

Kant dismissed Tiedemann's arguments, which he reasoned were caused by a lack of understanding.

Tiedemann was a pioneer of empirical psychology, and an early practitioner in regard to scientific study of child development.

He kept a journal of his son's sensory, motor, language, and cognitive behavior during the first thirty months of his life.

Through empirical observation, he claimed that children possessed a "pre-linguistic knowledge".