What is this thing called love?

By Peter Hankins

Edge has excerpted the first chapter of Marvin Minsky's book on emotions, The Emotion Machine: Commonsense Thinking, Artificial Intelligence, and the Future of the Human Mind. I clearly need to read the whole book, but I found the excerpt characteristically thought-provoking. As you might have expected, the general approach builds on The Society of Mind: emotions, it seems, allow us to activate the right set of resources (their nature deliberately kept vague) from the diffuse cloud available to us. So emotions really serve to enhance our performance: in young or unsophisticated organisms they may be a bit rough and ready, but in adult human beings they are under a degree of rational control and are subject to a higher level of continuity and moderation.

At first sight, explaining the emotions by identifying the useful jobs they do for us seems a promising line of investigation. Since we are the products of evolution, it seems a good hypothesis to suppose that the emotional states we have developed must have some positive survival value. The evidence, moreover, seems to support the idea to some degree: anger, for example, corresponds with physiological states which help get us ready for fighting. Love between mates presumably helps to establish a secure basis for the production and care of offspring. The survival value of fear is obvious.

However, on closer examination things are not so clear as they might be. What could the survival value of grief be? It seems to be entirely negative. Its physiological manifestations range from the damaging (loss of concentration and determination) to the surreal (excessive water flowing from the tear-ducts down the face). Darwin himself apparently found the crying of tears a puzzler -- with no practical advantages either to modern humans or to any imaginable ancestor, or any intelligible relationship to any productive function -- what has rinsing out your eyes got to do with the death of a mate or child? If it comes to that, even anger is not an unalloyed benefit: a man in the grip of rage is not necessarily in the best state to win an argument, and it's surely even debatable whether he's more likely to win a fight than someone who remains rational and judicious enough to employ sensible tactics.

One of the thoughts the extract provoked in me, albeit at a tangent to what Minsky is saying, concerned another possible problem with evolutionary arguments. The physiological story about an increased pulse rate and the rest of it is one thing, but does all that have to be accompanied by feeling angry? Can't we perhaps imagine going through all the right physiological changes to equip us for fighting, fleeing, or whatever other activity seems salient, without having any particular feelings about it?This sounds like qualia. If emotions are feelings which are detachable from physical events, are they, in themselves, qualia? I'm not quite sure what the orthodox view of this is: I've read discussions which take emotions to be qualia, or accompanied by them, but the canonical examples of qualia -- seeing red and the rest of it -- are purely sensory. The comparison, at any rate, is interesting. In the case of sensory qualia there are three elements involved: an object in the external physical world, the mechanical process of registration by the senses, and the ineffable experience of the thing in our minds, where the actual redness or sounding or smelliness occurs. In the case of the emotions, there isn't really any external counterpart (although you may be angry or in love with someone, you perceive the anger or love as your own, not as one of the other person's qualities): the only objective correlate of an emotional quale is our own physiological state.

Are emotional zombies really possible? It's widely though not universally believed that we could behave exactly the way we do -- perhaps be completely indistinguishable from our normal selves -- and yet lack sensory qualia altogether. An emotional zombie, along similar lines, would have to be a person whose breathing and pulse quickened, whose face blushed and voice turned hoarse, and who was objectively aware of these physiological manifestations, but actually felt no emotion whatever. I think this is still conceivable, but it seems a little stranger and harder to accept than the sensory case. I think in the case of an emotional zombie I should feel inclined to hypothesise a kind of split personality, supposing that the emotions were indeed being felt somewhere orin some sense, but that there was also a kind of emotionless passenger lodged in the same brain. I don't feel similarly tempted, with sensory zombies, to suppose that real subjective redness must be going on in a separate zone of consciousness somewhere in the mind.

The same difference in plausibility is visible from a different angle. In the case of sensory qualia, we can worry about whether our colour vision might one day be switched, so that what previously looked blue now looks yellow, and vice versa. I suppose we can entertain the idea that Smith, when he goes red in the face, shouts and bangs the table, is feeling what we would call love; but it seems more difficult to think that our own emotions could somehow be switched in a similar way. The phenomenal experience of emotions just seems to have stronger ties to the relevant behaviour than phenomenal experience of colours, say, has to the relevant sensory operations.

It might be that this has something to do with the absence of an external correlate for emotions, which leaves us feeling more certainty about them. We know our senses can mislead us about the external world, so we tend to distrust them slightly: in the case of emotions, there's nothing external to be wrong about, and we therefore don't see how we could really be wrong about our own emotions. Perhaps, not entirely logically, this accounts for a lesser willingness to believe in emotional zombies.

Or, just possibly, emotional qualia really are tied in some deeper way to volition. This is not so much a hypothesis as a gap where a hypothesis might be, since I should need a plausible account of volition before the idea could really take shape. But one thing in favour of this line of investigation is that it holds out some hope of explaining what the good of phenomenal experience really is, something lacking from most accounts. If we could come up with a good answer to that, our evolutionary arguments might gain real traction at last.

Peter Hankins is author of the Conscious Entities weblog.