The greatest and most influential of Plato‘s students was Aristotle, who established his own school at Athens. Although his writing career probably began with the production of quasi-Platonic dialogues, none of them have survived. Instead, our knowledge of Aristotle’s doctrines must be derived from highly-condensed, elliptical works that may have been lecture notes from his teaching at the Lyceum. Although not intended for publication, these texts reveal a brilliant mind at work on many diverse topics.

Philosophically, the works of Aristotle reflect his gradual departure from the teachings of Plato and his adoption of a new approach. Unlike Plato, who delighted in abstract thought about a supra-sensible realm of forms, Aristotle was intensely concrete and practical, relying heavily upon sensory observation as a starting-point for philosophical reflection. Interested in every area of human knowledge about the world, Aristotle aimed to unify all of them in a coherent system of thought by developing a common methodology that would serve equally well as the procedure for learning about any discipline.

Aristotelian Teachings

According to Aristotle there are four main causes of change in nature: the material cause, the formal cause, the efficient cause, and the final cause. In his own words:

“Cause” means: (a) in one sense, that as the result of whose presence something comes into being – e.g. the bronze of a statue and the silver of a cup, and the classes for which contain these;

(b) in another sense, the form or pattern; that is, the essential formula and the classes which contain it – e.g. the ratio 2:1 and number in general is the cause of the octave – and the parts of the formula.

(c) The source of the first beginning of change or rest; e.g. the man who plans is a cause, and the father is the cause of the child, and in general that which produces is the cause of that which is produced, and that which changes of that which is changed.

(d) The same as “end”; i.e. the final cause; e.g., as the “end” of walking is health.For why does a man walk? “To be healthy,” we say, and by saying this we consider that we have supplied the cause. (e) All those means towards the end which arise at the instigation of something else, as, e.g. fat-reducing, purging, drugs and instruments are causes of health; for they all have the end as their object, although they differ from each other as being some instruments, others actions.

~Metaphysics 1013a, translated by Hugh Tredennick

Aristotle’s systematic treatises may be grouped in several divisions:

• Logic
  1. Categories (10 classifications of terms)
  2. On Interpretation (propositions, truth, modality)
  3. Prior Analytics (syllogistic logic)
  4. Posterior Analytics (scientific method and syllogism)
  5. Topics (rules for effective arguments and debate)
  6. On Sophistical Refutations (informal fallacies)
• Physical works
  1. Physics (explains change, motion, void, time)
  2. On the Heavens (structure of heaven, earth, elements)
  3. On Generation (through combining material constituents)
  4. Meteorologic s (origin of comets, weather, disasters)
• Psychological works
  1. On the Soul (explains faculties, senses, mind, imagination)
  2. On Memory, Reminiscence, Dreams, and Prophesying
• Works on natural history
  1. History of Animals (physical/mental qualities, habits)
  2. On the parts of Animals
  3. On the Movement of Animals
  4. On the Progression of Animals
  5. On the Generation of Animals
  6. Minor treatises
  7. Problems
• Philosophical works
  1. Metaphysics (substance, cause, form, potentiality)
  2. Nicomachean Ethics (soul, happiness, virtue, friendship)
  3. Eudemain Ethics
  4. Magna Moralia
  5. Politics (best states, utopias, constitutions, revolutions)
  6. Rhetoric (elements of forensic and political debate)
  7. Poetics (tragedy, epic poetry)