"Vengeance on a dumb brute!" cried Starbuck, "that simply smote thee from blindest instinct! Madness! To be enraged with a dumb thing, Captain Ahab, seems blasphemous."
"Hark ye yet again- the little lower layer. All visible objects, man, are but as pasteboard masks. But in each event- in the living act, the undoubted deed- there, some unknown but still reasoning thing puts forth the mouldings of its features from behind the unreasoning mask. If man will strike, strike though the mask! How can the prisoner reach outside except by thrusting through the wall? To me, the white whale is that wall, shoved near to me. Sometimes I think there's naught beyond. But 'tis enough. He tasks me; he heaps me; I see in him outrageous strength, with an inscrutable malice sinewing it. That inscrutable thing is chiefly what I hate; and be the white whale agent, or be the white whale principal, I will wreak that hate upon him. Talk not to me of blasphemy, man; I'd strike the sun if it insulted me.--Moby Dick, Chapter 36, by Herman Melville
Ahab does not distinguish between whale, sun and man. All are pasteboard masks, all giving the appearance of order or truth, but hiding some as yet unknown power or force. Does it make sense to punish a whale or strike the sun if we feel it has done us wrong? What about punishing a person? At what point can we say that an entity--whale, sun, or human being--deserves to feel the force of our wrath?
Ahab hates Moby Dick because he sees malice in the whale. Is the whale the source, the ultimate cause of this malice? In other words, is Moby Dick the "principal"? Or is the white whale merely an agent of another's will? It does not matter, says Ahab. The whale is all he has to fight against. If there is some other power beyond the whale, then he will strike at it by striking the whale itself.
I don't want to get into whether or not Ahab is right to hate Moby Dick, or whether his fight against Moby Dick is rational. What interests me is the distinction between principal and agent, and whether or not we should follow Ahab's lead in rejecting it.
Let's approach this in philosophical terms. When we are talking about sources of intentional action--minds capable of acting on reasons--we are taking what Daniel C. Dennett calls the intentional stance. Taking the intentional stance is treating an entity as if it had beliefs and desires, and the capacity to act rationally on them. So, if Ahab were to regard Moby Dick as the principal--the reasoner behind the malice--then he would be treating Moby Dick as a rational agent with beliefs and desires. Starbuck says this is blasphemous. We should not treat whales as if they were rational agents. Ahab says that he would treat the sun the same way. In other words, he would treat the sun as an intentional agent, too.
But wait. Ahab does not exactly say that he is treating Moby Dick as a rational agent. He says it doesn't matter. Ahab is equally fine regarding the whale as an agent of another's will. In other words, he is fine treating the whale as if it were designed in order to serve some purpose. So the whale might be understood as the intentional creation of another's will. To treat the whale this way, we would be taking what Dennett calls the design stance. This is just the intentional stance applied to artifacts. To take the design stance, you imagine an object as the product of some intentional design. You imagine how the designer intended the object to function--you imagine what beliefs the designer had and what desires the object was meant to satisfy. In doing so, you can predict how the object will behave. So, Ahab can treat the whale as a "blind brute," an unthinking robot which is merely carrying out a program designed by some other intelligent being.
Ahab says it doesn't matter. Either way, we are imagining the actions of the whale as the result of intention--as the result of beliefs and desires. But it does seem to matter, doesn't it? Don't we want to know if the whale is an intelligent creature?
Let's look at another example: a thermostat. Dennett says that we can treat thermostats with the intentional stance. We can imagine them as having a rudimentary set of beliefs and desires, and this allows us to predict how they will respond to changes in room temperature. But, of course, we know that thermostats are designed. So we can (and should, I would say) take the design stance towards them. They do not have beliefs and desires of their own, but are artifacts which carry out the intentions of their designers.
Dennett says that there is no real difference here. He rejects the distinction between "original intentionality" and "derived intentionality." In other words, there is no difference between treating an object as having beliefs and desires of its own and treating it as if it is carrying out the intentions of some other agent. It would seem Dennett agrees with Ahab, then. It does not matter if Moby Dick is principal or merely agent.
Should we be satisfied with this approach? Well, what of a mercury thermometer? Like a thermostat, it tells the temperature. And like the thermostat, it was designed. When I take up the design stance towards the mercury thermometer, I am taking up the intentional stance towards its designer. So, following Ahab and Dennett, I should not think there is a significant difference here. I may as well treat the mercury thermometer as a rational agent in its own right. Ahab and Dennett lead us to conclude that any designed object can be regarded as a rational agent with beliefs and desires of its own.
Ahab goes one step further. He says the sun, too, can be regarded in the same way. And indeed, why not? Well, we might object that the sun was not designed. We certainly have no evidence that it was designed. But that is not the deciding factor. According to Dennett, the intentional stance is justified just in case it is useful as a predictive strategy. If we can make successful predictions about the sun by taking up the intentional stance towards it, then we are justified in doing so.
It's natural to use the language of intentionality to talk about natural processes. We usually refer to this as personification and metaphor. However, Dennett's view is that, when it comes to using the intentional stance, then it is not a metaphor. If we are making successful predictions about the sun's behavior, we are dealing with a real intentional system--as real as any can be.
It goes without saying that people have, throughout history, regarded the sun, the moon and countless other natural objects as intentional agents. They made predictions on this basis--some more successful than others--but they did the best they could. Aristotle (and others) regarded all entities in teleological terms, and made reasonably successful predictions accordingly. We therefore can say that it is justifiable to regard even the sun as a rational agent, or as exhibiting the intentions of some other agency. Remember, Ahab and Dennett say there is no significant difference.
I, for one, am not satisfied by this approach. There are obvious advantages to distinguishing between rational agents and mere artifacts. We should not regard a clock as a rational agent merely because it carries out the intentions of its designer. We should not regard any complex computer as a rational agent merely because it carries out the intentions of its designer. It is not enough to say that the intentional stance is useful and successful. To say that an object is a rational agent, we should have some means of determining whether or not the intentional stance is justifiable as opposed to the design stance. That is, we should think we are dealing with rational agency if and only if we are dealing with apparently rational behaviour which cannot be explained as the result of another agent's intentions.
We can explain the behaviour of the sun without appealing to rational agency of any sort. Therefore, we should not regard the sun as an intentional system. We can thoroughly explain the behaviour of a thermostat by appeal to the designer's intentions, and so we should not regard a thermostat as a rational agent. The same goes for more advanced systems, like chess-playing computers. Human beings, however, appear to be rational agents and we have no explanation for our behaviour as the result of any other agent's intentions. Therefore, we are justified in regarding ourselves as rational agents.
In short, Ahab is wrong. And so is Dennett.
P.S. I realize I have not given necessary or sufficient conditions for rational behaviour here. Perhaps a sufficient condition is something like what Dennett suggests: That we are justified in regarding an entity as a rational agent if doing so leads to successful predictions. I am just adding the caveat that we must not be able to explain the behaviour as the result of another agent's design. I would also add that whether or not an entity really is a rational agent is not merely a matter of whether the intentional stance can be used to make predictions about the system, but a matter of whether or not the intentional stance is necessary to make the best possible predictions about the system in question. So, people may be justified in using the intentional stance to talk about the sun, but there is a real sense in which they are wrong. We do not need the intentional stance to make the best possible predictions about the sun. I believe we do need the intentional stance to make the best predictions possible about human beings. This conclusion is based on the fact that we do, in fact, apply the intentional stance. Perhaps we do so by design--but even then, we are still taking up a predictive strategy, which means we still have beliefs and desires. So even if we are designed, we are rational agents. (There's no reason to assume that rational agents cannot be designed.) The fact that we do take up the intentional stance proves that we are rational agents. As such, we must be regarded as rational agents or we will not be fully understood. We might suppose that some alien creatures could make predictions about our bodily movements without regarding us as rational agents. However, all this shows is that we--our identity as rational agents--is not defined by our bodily movements. We may supervene on our bodily movements, but we are not identifiable with them. So those aliens will not be describing human action. They will only be describing bodily movements. And since human action is real, their descriptions will be incomplete. At least, that's the position I'm leaning towards now.