[6] He declined the offer of a classical chair at Kiel, and accepted a post as tutor to the son of an intimate friend of Karl vom Stein zum Altenstein, the Prussian minister of education.

He held this position for seven years (1826–1833), occupying his leisure time with the preparation of a critical edition of Aristotle's De anima (1833; 2nd ed.

[6] For nearly 40 years, he proved himself markedly successful as a teacher, during the greater part of which time he had to examine in philosophy and pedagogics all candidates for the scholastic profession in Prussia.

Trendelenburg's philosophizing is conditioned throughout by his loving study of Plato and Aristotle, whom he regards not as opponents but as building jointly on the broad basis of idealism.

Proceeding on the principle that like can only be known by like, Trendelenburg next reaches a doctrine peculiar to himself (though based upon Aristotle) that plays a central part in his speculations.

It is true that matter can never be completely resolved into motion, but the irreducible remainder may be treated, like Aristotle, as an abstraction we asymptotically approach but never reach.

On the other side stands the organic or teleological view of the world, which interprets the parts through the idea of the whole, and sees in the efficient causes only the vehicle of ideal ends.

The latter view, which receives its first support in the facts of life, or organic nature as such, finds its culmination and ultimate verification in the ethical world, which essentially consists in the realization of ends.

In Trendelenburg's treatment of the state, as the ethical organism in which the individual (the potential man) may be said first to emerge into actuality, we may trace his nurture on the best ideas of Hellenic antiquity.