Here are two rough, but not bad, summaries of what compatibilists and incompatibilists say.
Incompatibilists say that your behavior is free only if it is not caused to happen by things outside of your control.
Compatibilists say that your behavior is free if nothing prevents you from doing what you want to do.
Kensi asked a good question about the compatibilist side. What if there is nothing preventing you from doing a thing that you want to do but, at the same time, you wish that you did not want to do it? Addictions provide good examples here: I want to smoke, because I am addicted to nicotine, but I wish that I did not have this desire and that I was not a smoker.
Compatibilists seem to say you are free to smoke. And maybe that is the right answer. But Frankfurt is going to try to accommodate the thought that Kensi had, namely, that sometimes you are not free even when you are doing what you want to do. Can he pull it off?
His question: what is a person? What distinguishes persons from other creatures?
One answer to this kind of question involves our intellectual powers. What is unique about people is that they are rational; non-human animals are not.
Frankfurt is going to give a different answer. Here it is.
It is my view that one essential difference between persons and other creatures is to be found in the structure of a person’s will. Human beings are not alone in having desires and motives, or in making choices. They share these things with the members of certain other species, some of whom even appear to engage in deliberation and to make decisions based upon prior thought. It seems to be peculiarly characteristic of humans, however, that they are able to form what I shall call “second-order desires” or “desires of the second order.” (Frankfurt 1971, 6)
It is pretty obvious that “second-order desire” is an important concept. This is where he defines it.
A first-order desire is a desire to do something. (Frankfurt 1971, 7)
The will is a first-order desire that moves one to act (Frankfurt 1971, 8)
A second-order desire is a desire to have a first-order desire (Frankfurt 1971, 8–9)
A second-order volition is a desire that a first-order desire be my will, that is, move me to act rather than just being something that I want. (Frankfurt 1971, 10)
The point of the example about the doctor who wants to experience the cravings that his addicted patients feel is to distinguish between a second-order desire and a second-order volition. The doctor wants to understand what it is like to have the desires of an addict but does not want to actually be addicted or take drugs. The doctor does not have a second-order desire for an effective first-order desire, so it is not relevant to the will. (Frankfurt 1971, 9)
Second-order volitions are second-order desires for effective desires, desires that motivate action.
Claim: “it is having second-order volitions, and not having second-order desires generally, that I regard as essential to being a person.” (Frankfurt 1971, 10)
Now we have a new term: “wantons.” Wantons are creatures that have first-order desires but no second-order volitions. Wantons include all non-human animals, young human children, and some adult human beings. Wantons can be rational, but they do not care about what their will is (Frankfurt 1971, 11). This is why he thinks that rationality is not the essential feature of persons.
Illustration of the difference between wantons and persons: Two drug addicts (Frankfurt 1971, 12).
Unwilling addict: wants to not want to take drugs (but can’t).
Wanton addict: never occurs considers whether he wants to want to continue taking drugs or not.
The wanton can have conflicting first-order desires, but he doesn’t have a preference about which desires win the conflict. (Frankfurt 1971, 12)
The unwilling addict, by contrast, “may meaningfully make the analytically puzzling statements that the force moving him to take the drug is a force other than his own, and that it is not of his own free will but rather against his will that this force moves him to take it.” (Frankfurt 1971, 13)
Now we get to free will. Woo hoo!
Frankfurt claims that having a free will means being free to will what one wants to will.
Here is an easier way to put it: the first and second-order desires are in conformity with one another.
It is in securing the conformity of his will to his second-order volitions, then, that a person exercises freedom of the will. And it is in the discrepancy between his will and his second-order volitions, or in his awareness that their coincidence is not his own doing but only a happy chance, that a person who does not have this freedom feels its lack. (Frankfurt 1971, 15, emphasis added)
The unwilling addict’s will is not free because it is not the will that he wants to have.
The wanton’s will is not free either. He has no second-order volitions and so there is no such thing as the conformity of his first and second-order desires.
Frankfurt says his theory satisfies two conditions better than the alternatives (Frankfurt 1971, 17).
It accounts for our disinclination to say that non-human animals have free will.
It explains why free will is thought to be desirable. Those who have free will, as Frankfurt describes it, will have satisfied their second-order desires. (Frankfurt 1971, 17)
He contrasts his position with that of a philosopher named Chisholm who was a libertarian: “Whenever a person performs a free action, according to Chisholm, it’s a miracle.” The movement of a hand is the outcome of a series of physical causes but at some point in the chain one event “‘was caused by the agent and not by any other events.’” (Frankfurt 1971, 18, quoting Chisholm)
Frankfurt makes two points.
Rabbits could do the same thing.
No one cares about the ability to interrupt the natural order of causes.
Finally, there is a question: does moral responsibility require freedom of the will? Frankfurt thinks it does not: it only requires that you act freely, or act “of your own free will” (Frankfurt 1971, 19). So what’s the difference between having “freedom of the will” and acting “of you own free will”?
Having freedom of the will means you are free to have the will the you want to have, meaning that your will could have been other than it is.
Acting freely or acting of your own free will means that your action is caused by a first-order desire that conforms with your second-order volitions.
Suppose that a person has done what he wanted to do, that he did it because he wanted to do it, and that the will by which he was moved when he did it was his will because it was the will he wanted. Then he did it freely and of his own free will. Even supposing that he could have done otherwise, he would not have done otherwise; and even supposing that he could have had a different will, he would not have wanted his will to differ from what it was. Moreover, since the will that moved him when he acted was his will because he wanted it to be, he cannot claim that his will was forced upon him or that he was a passive bystander to its constitution. Under these conditions, it is quite irrelevant to the evaluation of his moral responsibility to inquire whether the alternatives that he opted against were actually available to him. (Frankfurt 1971, 19)
He illustrates the point with the example of the willing addict. The willing addict has second-order volitions, like the unwilling addict, but he is delighted by his condition.
The willing addict’s will is not free because he will have the first-order desire to take drugs regardless of what his second-order volition is.
But when he does take drugs, given what his second-order volition in fact is, “he takes it freely and of his own free will” (Frankfurt 1971, 19).
I think an incompatibilist will pretty clearly have a different understanding of that example. It is worth talking about how the contending sides would disagree here.
Look at his main statement of what free will consists in again.
It is in securing the conformity of his will to his second-order volitions, then, that a person exercises freedom of the will. And it is in the discrepancy between his will and his second-order volitions, or in his awareness that their coincidence is not his own doing but only a happy chance, that a person who does not have this freedom feels its lack. (15, emphasis added, see below)
Does it matter how that conformity is secured? What if your mind is in lock step because of, yes, causes outside of your control, such as, say, your upbringing?
Here is another question. Are your second order desires always what you really want to do? Try to think of a case where someone wishes they didn’t have the first-order desires that they do but would really be more free if they acted on the first order desires than if they acted on the second-order desires.
Third, why stop at the second order? What about third order volitions? Or fourth?