Practical Reason and the Unity of Agency

Self-Constitution is a thrillingly ambitious book. Ranging widely over both historical and contemporary debates in ethics and the philosophy of agency, Korsgaard sets herself the task of answering some of the hardest questions moral philosophy has to ask. It is required reading for anyone with interests in agency, practical reason, personal identity, or the ethical teachings of Plato, Aristotle, Hume, or Kant. It is also that rarest of academic books: a major contribution to ongoing debate written with such warmth, wit, and clarity as to make it accessible to almost any reader. In short, and notwithstanding its failure to fully convince at least this reader of its conclusions, Self-Constitution is a splendid piece of philosophy.

The book has three main themes: 'the nature of action, the constitution of personal or practical identity, and the normativity of the principles of practical reason' (1.1.6),¹ though it is the last of these that gives the book its unifying structure. As in her earlier Sources of Normativity,² Korsgaard sets herself the problem of showing how the principles of practical reason (thought of as including the foundational principles of morality) attain their authority over us. Her answer, which she argues is also that given by Plato and Kant, is that the principles of practical reason are constitutive of agency itself, so that anyone who is trying to act — anyone who is trying to be an agent — is thereby necessarily trying to conform to them. Thus agents are subject to the principles of practical reason simply through their ongoing commitment to being agents. Moreover, we have no choice but to act, for the simple reason that whatever results from choice is an action: 'choosing not to act makes not acting a kind of action' (1.1.1). So we have no choice but to be agents, and therefore no choice but to be practically rational.

The apparent strength of this conclusion calls to mind Robert Nozick's observation about the typical impotence of philosophical arguments:

Perhaps philosophers need arguments so powerful they set up reverberations in the brain: if the person refuses to accept the conclusion, he dies. How's that for a powerful argument? Yet, as with other physical threats ('your money or your life'), he can choose defiance. A 'perfect' philosophical argument would leave no choice.³

Korsgaard may be read as trying to provide precisely such a 'perfect' argument. On her view, action is self-constitution, and one constitutes oneself as an agent by choosing in accordance with the principles of practical rationality. Her idea is not that the irrational or immoral agent is somehow forced to mend his ways, say by some sanction of nonexistence; the picture is not one in which there first exists an agent who then chooses irrationality and as a result goes up in a puff of smoke. Rather, the entity that 'chooses' irrationality simply fails to constitute itself as an agent in the first place — and so does not choose anything at all (1.4.2). If successful, Korsgaard's argument shows that we quite literally have no choice but to (attempt to) act in accordance with the principles of practical reason. That conclusion is enticingly strong.

To get to it, Korsgaard faces three major tasks: (1) establishing that the principles of practical reason are constitutive of agency; (2) establishing that the principles of practical reason entail the principles of morality; and (3) explaining how, if this is true, irrational and immoral action are possible. For various presentational reasons Korsgaard tackles (3) in advance of (2), and this discussion follows her ordering. In it I highlight some key moves in her argument that failed to convince, and suggest places where I feel more could usefully be said. My focus throughout is on Korsgaard's problematic — to my mind — notion of agential unity. I begin with (1).

I The Principles of Practical Reason

According to Korsgaard, to act is to constitute yourself as the cause of...