Introduction
Practical deliberation - bouleusis - is discussed by Aristotle in books 3 and 6 of the Nicomachean Ethics. Although Aristotle doesn't mention this, it is necessary to distinguish practical deliberation from what may be called "cognitive deliberation". Cognitive deliberation is deliberation over whether something is true or false, while practical deliberation is over what to do. In jury trials for example the jury is asked to decide the cognitive question, is the accused guilty as charged? Its deliberations concern this matter exclusively. If the judgment is "guilty", the judge must deliberate about something quite different, viz. what sentence to impose. The jury's deliberations are cognitive, the judge's practical. In this chapter, I shall be concerned with practical deliberation.
Aristotle makes two remarks about deliberation that are familiar to every philosopher: first that we deliberate about means not ends, and secondly that we deliberate about things that are in our power and can be done (EN 1112a30, 1112b11-16, 1139b6, 1140a32). I need a table; to make a table requires a hammer and saw; I have a hammer but no saw; so let me go out and buy a saw. Again a doctor, qua doctor, does not deliberate about whether a patient should be healed, but how to heal him. No one will disagree with this. To be sure, one can imagine circumstances in which a doctor might deliberate over whether a patient should be healed, say if there were 1000 patients and drugs for only 500. But in this case the doctor isn't really deliberating about ends, but about the practical problem of how to treat as many people as possible with the means available. If a doctor were truly to deliberate about ends and ask for example, "Is healing worthwhile?" then that would fall under cognitive rather than practical deliberation.
What exactly is deliberation? In what follows I try to give a philosophically adequate account of it, and to answer some difficult questions. I finish up by speculating about what sorts of structures and neurophysiological functioning in the brain would make possible in real life the philosophical description of the deliberative process that I have given.
Deliberation
Let's start off with a concrete example. Marsha has to decide whether to accept an offer of graduate study in philosophy at UBC, Western Ontario or McGill. Call these alternatives A, B and C. Each one has its advantages and its disadvantages, and it is important to make the right decision. Marsha deliberates.
The first step in the deliberative process is to be clear about the alternatives, to represent them accurately and keep them in focus. Is the list exhaustive? Should she make a last-minute application to McMaster, where her sister is studying? Should she simply do nothing, and not accept any of the offers? Call this last option D, the do-nothing alternative. Let's suppose that A, B, C and D exhaust the alternatives facing her, and that each one is a "live" alternative in the sense that (i) she can choose it, and (ii) if she chooses it her choice determines what happens subsequently. Thus if she chooses UBC, she goes to UBC. We may imagine that Marsha has lined up three envelopes on her desk, addressed to UBC, Western and McGill. All she has to do is to put a stamp on one of them and mail it, or alternatively forget about graduate study. The first requirement for deliberation, then, is the existence of a "choice set", a set of two or more alternative courses of action (A, B, C, D,...) each of which it is physically possible for the deliberator to perform or implement, and which together exhaust the available options.
Once the choice set has been established, the process of deliberation begins in earnest. Each option has its advantages, which constitute the reasons for choosing it, and its disadvantages, which constitute the reasons for not choosing it.
I shall call these deliberation reasons. For example UBC has made a generous scholarship offer, but on the other hand has no member of staff who works directly in Marsha's area of interest. These facts constitute positive and negative deliberation reasons for A, and there will be other positive and negative deliberation reasons for B, C, and D. In deliberation, we weigh deliberation reasons. We compare their relative strength with the aim of arriving at an overall comparative evaluation. The process of evaluation is normally but not invariably the most time-consuming part of deliberation, and ideally should result in a list of the options ordered by preference.
Once evaluation is completed, it might seem that the deliberative process is at an end. But this is not so. There is one more step, frequently ignored in studies of rational choice and decision but still essential: the element of choice or decision itself It may seem difficult to imagine, once an ordered evaluation of the options has been made, what more a deliberator could need. But suppose the first two alternatives are very close in the ordering? Suppose they come out equal? What if the deliberator is faced with a difficult decision? Even in the case where an evaluation is unambiguous, with a clear-cut winner, something else besides evaluation is needed for action. The missing element is what Aristotle call prohairesis, deliberative choice.
More needs to be said about prohairesis, but we should first sum up what has been established so far. Our philosophical account of deliberation has distinguished three separate components of the deliberative process, ordered in strict temporal sequence:
(i) Representation of the alternatives,
(ii Evaluation,
(iii) Choice.
With decision, which is choice of one of the alternatives, the deliberative process ends. We turn now to decisions and the reasons for them, the latter being distinct from the deliberation reasons for the different options.
