Levels of Argument: A Comparative Study of Plato's Republic and Aristotle's Nicomachean Ethics by Dominic Scott (review)

The results of this comparison of the Republic and the Nicomachean Ethics (EN) can be summed up thusly: (i) the texts share the same methodology, (ii) this methodology is based on a functional account of human nature, and (iii) whereas Plato believes that political philosophy needs grounding in metaphysics, Aristotle considers such a thing possible but superfluous.

I shall here focus on (i) exclusively. The shared methodology is characterized by two Platonic similes: the cave from the Republic, and the racecourse simile that Aristotle attributes to Plato in EN 1.4. Both represent a research program with three steps: starting from ordinary intuitions about political matters and ascending towards higher principles, grasping these highest principles and, finally, returning to the initial starting points. At the third and final step, the political philosopher applies his knowledge of the highest principles in explanations of the initial intuitions and intervenes in his society with a view to improving his fellow citizens through education and lawgiving.

This three-step methodology operates on two levels of argumentation: one that uses ordinary opinions and experience as a basis for its conclusions; another that uses metaphysical principles. The levels are distinguished in terms of precision and explanatory power. Borrowing a phrase from Plato, Scott calls them the shorter and the longer routes. Both routes are circular in that they return to their initial starting point in their final steps.

Socrates travels the shorter route in Republic 2–4 and 8–9, but offers only a description of the longer route in books 5–7. Whereas interpreters usually focus on the longer route, Scott has much to say about the shorter one. Most importantly, the shorter route has a more empirical basis than what we usually expect of Plato. In almost all cases, the shorter route does not presuppose the metaphysics of the central books (28). This is quite provocative. If Scott is right, how does he suppose that the shorter and longer routes relate to one another? It seems that he saddles the Republic with a version of the chorismos: if the two routes are completely independent of one another, but lead to the same conclusions, how then are the forms explanatorily relevant for Plato's political philosophy as found in the Republic? The problem is aggravated by the fact that there are indeed metaphysical assumptions on the level of the shorter route; Scott talks about a "middle route" that involves certain metaphysical assumptions (54). However, these are not the metaphysical claims found on the longer route. So it seems that we are left with a set of unwarranted metaphysical assumptions. The thing is that Plato nowhere takes the longer route. It is left as a necessary but unaccomplished condition for his political thought.

Aristotle travels the shorter route in the EN, moving towards the principle: a definition of eudaimonia. He believes that the longer route is possible, but that its pursuit would be counterproductive in a political treatise aimed at action rather than knowledge (118–21). The longer route would lead into theoretical philosophy in order to clarify the terms of the definition of eudaimonia. Aristotle thinks that the philosophy of human affairs will only be complete if a return to the starting points is made, as is clear from EN 10.9. Here, Aristotle advocates the student's engagement in matters concerning real politics. It would be natural to suppose that the ascent from the principles was to be found in the Politics, especially books 7–8. In that case, the account in the Politics would have to rely on the definition of eudaimonia from the EN. But Aristotle relies on exoteric works here and not on the EN (181–85). So Aristotle never attempts the downward move toward the starting points of political philosophy. Let me add that the reliance of the Politics on the EN would also be challenged by...