Aristotle
An act is not virtuous if the act itself is of a certain kind,
but only if in addition the agent has certain characteristics as he performs it:
first of all, he must know what he is doing; secondly, he must choose it for its own sake;
and third, the act must spring from a firm and unchangeable character.
...Yet most men do not perform such acts, but by taking refuge in argument they ... act like sick men
who listen attentively to what the doctor says, but fail to do any of the things he prescribes.
For the Historical Origins of the Problem of the Practicality of Reason, see:
Wyner, Garret: Toward a Phenomenology of Conscientious Action
and a Theory of the Practicality of Reason
Primary Sources:
J. Barnes ed: The Complete Works (2 Volumes)
McKeon ed: The Basic Works of Aristotle
W.D. Ross: Aristotle's Metaphysics
M. Ostwald trans: Nicomachean Ethics
A Few Secondary Sources:
J. Owens: The Doctrine of Being in the Aristotelian Metaphysics
H. Joseph: Essays in Ancient & Modern Philosophy
J. Moravcsik ed: Aristotle a Collection of Critical Essays
J. A. Stewart: Notes on the Nicomachean Ethics of Aristotle 2 Volumes
J. Barnes ed: Articles on Aristotle: Ethics & Politics
A. Kenny: Aristotle's Theory of the Will
A. Rorty: Essays on Aristotle's Ethics
H. Wolfson: Cresca's Critique: Aristotle's Physics in Jewish & Arabic Philosophy
T. Aquinas: Commentaries on Aristotle
F. Brentano (see Resource Page)