From the philosophical archive for the constructive study of ontological dualism:

Why Must Homunculi Be So Stupid?1

Elliott Sober

quoted from: Mind (1982) Vol. XCI, 420-422

Molière's joke about the sleeping potion's 'dormative virtue' is standard fare in the philosophy of mind. One cannot, so it is claimed, explain someone's seeing, or remembering, or intending something by postulating a little man in the head who looks at an image, retrieves a memory trace, or forms a resolve. Taking this lesson to heart, writers like Attneave [1960], Fodor [1968], and Dennett [1978] have argued that explanations of a mental capacity can only avoid the emptiness of Molière's dormative virtue by decomposing the capacity into a set of components which are more rudimentary. Postulating little men in the head is permissible, as long as the little men do not have the same full-blown abilities as the people they inhabit. Homunculi are all right, if they are stupid.

Rorty ([1979], p. 236) has observed that the pattern which allegedly vitiates smart homunculus explanations can be found in other sciences, but without such disastrous results. An explanation of why the bodies of the solar system revolve as they do may with impugnity invoke the idea that the bodies are composed of atoms whose components exhibit the same pattern of motion. Similarly, the digestive capacities of an organism may be explained perfectly well by the fact that it is the host of a parasite which itself has those very abilities. If smart homunculi confer the kiss of death in the context of psychological explanation, then perhaps we have at last uncovered what is unique about the mind. Whatever might be said of planets and parasites, and whatever promise there may be in Brentano's idea of intentionality, it would appear that stupidity is the mark of the mental.2

I suspect, however, that no such distinctive feature is at hand. What goes for physics and biology also applies to psychology. What, then, is wrong with smart homunculi? Why must homunculi be stupider than we are, if 'Chinese box explanations', as we might call them, are permitted in other domains?

Sometimes preferred explanations are empty because they rather obviously could not be true. The supposed problem with the evolutionary principle of the survival of the fittest amounts to the fact that one can't explain differences in actual reproductive success in terms of differences in fitness, if the fitness of an organism is simply identified with its actual reproductive success. The principle would then be devoid of explanatory power, and its explanatory emptiness reveals itself in the fact that certain explanatory stories cannot be right. Nothing explains itself, so fitness cannot explain reproductive success, if fitness is reproductive success.3

But this cannot be the source of the explanatory emptiness of postulating smart homunculi. If smart little men were surgically discovered to be mediating someone's inputs and outputs, wouldn't this explain his capacity to avoid walking into walls, to carry on sophisticated repartee, and to fulfil his basic and not so basic needs? The discovery of how his panel of intelligent homunculi were connected to stimuli on the one hand and to behaviour on the other would be very illuminating indeed. The explanatory emptiness of smart homunculi must have a different genesis.

Another variety of empty explanation is the kind which, though true, is uninformative. There is little doubt that Molière's potion is capable of putting you to sleep in virtue of its having some property or other which endows it with that capacity. But to say so is to say very little. The potion does have certain powers, but to leave it at that is to fail to dispel the mystery of how the potion is able to do what it does. But this, again, is not the problem with postulating smart homunculi. The problem here is not that the proferred explanation is true, but trivial. It is outrageous in its falsehood, implying a slew of startling, contentful, consequences.

Chinese box explanations-whether they involve smart homunculi, planetary atoms, or intestinal parasites-are capable of offering illumination in one explanatory context, but in another they are not. When we ask for causal explanation of token events or states of affairs, there is nothing in principle defective about such accounts. The planets moved as they did because their component atoms did the same. The organism was able to digest the food because its intestinal parasites could too. And it is conceivable that I am now seeing the page in front of me because a little man in my head is now looking at my retinal images.

Matters change, however, when we shift our request for explanation from token to type. If the question about the solar system is to understand what revolving is, it is no good being pointed to little atoms that do the same thing. Our question, still unanswered, would then involve grasping what unites planets and atoms. We might hope for help from the laws of motion. Similarly, if our interest in an organism leads us to ask about the nature of digestion as a kind of process, we are not helped by being told that the organism can digest partly because it contains a parasite which can too. Again, the result of this remark is merely to broaden the scope of our unanswered question. We now want to know what laws govern the way organisms obtain energy from their environments, and how these laws apply simultaneously to hosts and to the parasites they house.

So it is for the psychological. Our interest in this area of inquiry, as in other sciences, has at least two parts. First, there is the causal explanation of token events. Additionally, there is the task of understanding the character of various psychological types. Smart homunculi may explain why I now see the page in front of me, but they do not explain what seeing is. Chinese box explanation is to no avail here, and it is the importance of this explanatory problem which explains why homunculi must be so stupid.4

  1. This paper was written under grants from the John Simon Guggenheirn Foundation and from the University of Wisconsin, Madison, Graduate School. I also wish to thank the Museum of Comparative Zoology, Harvard University, for its hospitality during 1980-1
  2. Dennis Stampe has observed that a related doctrine, namely that a mark of the mental is the possibility of stupidity, lives on in the idea that the intensionality of belief locutions is a unique characteristic of the mind. Allegedly, an essential property of belief is that it be possible for one to believe P but not believe Q, when P and Q are logically equivalent. I argue in Sober [1982] that this sort of opacity is not specific to the mental.
  3. It is within the context of causal explanation that an object's having property P can't explain its having property Q, if P = Q. However, this does not rule out the possibility that another style of explanation, which we might call 'explanation by decomposition', may permit this pattern. Perhaps a gas' having a particular temperature could, in some sense, be explained by, the fact that the molecules of which it is made have a certain mean kinetic energy.
  4. If smart homunculi are not ruled out a priori, then Dennett [1978] is mistaken in his claim that it is a 'category mistake' to apply psychological predicates of the personal level (like 'see', 'believe', 'want', and 'intend') to objects at the subpersonal level.


Attneave, F. [1960], 'In Defence of Homunculi', in W. Rosenblith (ed.), Sensory Communication (MIT Press, Cambridge), pp. 777-782.

Dennett, D. [1978], Brainstorms (Bradford Books, Montgomery, Vermont).

Fodor, J, [1968], Psychological Explanation (Random House, New York).

Rorty, R. [1979], Philosophy and the Mirror of Nature (Princeton University Press, Princeton, N.J.).

Sober, E. [1982], 'Why Logically Equivalent Predicates May Pick Out Different Properties', American Philosophical Quarterly.