A judgment is the mental act by which one thing is affirmed or denied of another.

Logic is the science of the laws of thought, as thought,--that is of the necessary conditions to which thought considered in itself is a subject.

Metaphysics, in whatever latitude the term be taken, is a science, or complement of sciences, exclusively occupied with mind.

Consummated science is positively humble.

An instinct is an agent which performs blindly and ignorantly a work of intelligence and knowledge.

The pursuit of knowledge is but a course between two ignorances, as human life is itself only a wayfaring from grave to grave.

There is a distinction, but no opposition, between theory and practice. Each to a certain extent supposes the other. Theory is dependent on practice; practice must have preceded theory.