51动漫

The panel members were Chris Frith, professor of cognitive neurology at London鈥檚 Institute of Neurology; Shere Hite, author of the Hite Reports and professor of gender and society at Nihon University in Japan; Owen Holland, senior lecturer in computer science at the University of Essex; and Geshe Tashi Tsering, a Tibetan Buddhist monk and head of the Jamyang Buddhist Centre in London. Keeping the proceedings focused was Simon Blackburn, professor of philosophy at the University of Cambridge and author of Think

Chris Frith

When you spontaneously lift your finger, you are aware, first, of the urge to lift it and then, shortly afterwards, of lifting it. But the brain activity that goes with this simple action (as the famous work by Benjamin Libet shows), produces a time line for the physical event that is different from that of the mental event. On average, there is a change in brain activity almost a second before your finger 鈥渟pontaneously鈥� lifts, whereas the awareness of the intention to lift the finger happens considerably later. This has been replicated by my colleague, Patrick Haggard.

So does this observation eliminate the possibility of free will? I don鈥檛 think so. For me, the moment of freedom occurs much earlier. This delay in our awareness is to give us a sense of being in control of our movements.

There鈥檚 another aspect of the original Libet experiment. The awareness of initiating the act also happens at a different time from the physical event 鈥� earlier in this case, so you are aware of initiating the act about 80 milliseconds before your finger moves. The consequence is the intention and the action are pulled closer together in mental time compared to what happens in physiological time. So voluntary actions and their effects are experienced as being closer together in mental time than they are, while the opposite is true for involuntary movements. Haggard calls this 鈥渋ntentional binding鈥�.

But what if, rather than being told to lift your finger at a certain time, an experimenter lets you choose from four responses? Is this really a free-selection task? When Libet tells you to lift your finger whenever you feel the urge, you鈥檙e well aware he would be cross if you never had the urge. So you鈥檙e selecting from a specific sub-category of responses. Your interpretation is to try to produce non-obvious responses so the experimenter can鈥檛 predict what will happen next. Patients with damage to the prefrontal cortex show 鈥渦tilisation behaviour鈥�: they can鈥檛 resist making the obvious response. When the French neurologist Fran莽ois Lhermitte took one such patient round his flat, he showed him the bedroom and the patient undressed and climbed into bed!

Now, once we鈥檝e chosen from this restricted repertoire of responses, the selection of the individual response can be determined by the environment. We may decide to behave like a scientist, a citizen, or a hero, but having chosen, we can be driven by the environment. That is why I suggest that 鈥渇ree will鈥� occurs before the selection of a particular action.

Is the decision to behave in any particular mode somehow predetermined? I can鈥檛 answer that absolutely, but it seems clear that someone with frontal lobe damage or an animal with a less developed prefrontal cortex will have less free will because their behaviour is driven by the environment in a much more direct way. Studies of the brain certainly don鈥檛 eliminate free will, but may specify a bit more what we鈥檙e trying to talk about.

Shere Hite

In the discipline of intellectual history, which was my first field of study, we try to separate out the ideas that we learn and decide are our own (even if they鈥檙e not, but really ideas that society wants us to internalise) from those that we are truly expressing.

For me, the idea of the male 鈥渟ex drive鈥� is a classic example. It is discussed so often in the media as if it is a scientific precept 鈥� but I鈥檓 not so certain. It is hard to say if there is such a thing or if it is a product of ideology.

The common, clich茅d view of men鈥檚 sexuality is that men鈥檚 bodies contain a powerful mechanism called 鈥渟ex drive鈥� connected to 鈥渕ale hormones鈥�, and that sex drive makes men want to 鈥減enetrate鈥� and 鈥渋mpregnate women with their seed鈥�. Using the phrase 鈥渟ex drive鈥� seems to imply that sexual activity leading to reproduction is a biological imperative.

It may be that men really have a choice about how they want to express their sexuality. In fact, 鈥渟ex drive鈥� may be a deus ex machina, a concept designed to prove everything else, 鈥渟ince this, therefore that, obviously evident鈥濃�� But there is no proof whatsoever for its existence. The only 鈥渆vidence鈥� is circumstantial.

If the 鈥渕ale sex drive鈥�, the erect penis being biologically programmed to be attracted by the vagina of a reproductively aged female, exists 鈥渋n nature鈥�, then it should be possible to prove its existence scientifically. Hormones are usually cited as a 鈥減roof鈥� for the existence of the male sex drive. But it must still be demonstrated: first, how do hormones cause desire for orgasm, other than that they and orgasm coincidentally exist, and secondly, how exactly do hormones cause men to 鈥渘aturally鈥� focus on 鈥減enetration of the vagina鈥� of a woman, or 鈥渢he reproductive act鈥�?

The cause of a desire to orgasm is not scientifically known. 鈥淗ormonal urges for orgasm鈥� and focus on coitus are separate issues. Men have fluctuating sexual hormones that may or may not coincide with desire for orgasm. It is an age-old question: just how mechanical is male desire?

Most men in my research feel their desire is largely inspired by a particular desired individual, or by particular images or a fantasy 鈥� it does not come automatically or 鈥渕echanically鈥�, without their effort. Or if they get an erection at night during sleep, it doesn鈥檛 automatically make them feel they desire something or someone.

These questions science must answer. To simplistically assert: 鈥淚t鈥檚 a question of men鈥檚 sex drive鈥� doesn鈥檛 answer any questions. Using the concept of 鈥渟ex drive鈥� as a jack-in-the-box may be distorting both male and female sexuality. It puts everyone under pressure to have this mechanical idea of what is happening in the body.

Of course, if it can be proven that there is some mechanism we could call 鈥渟ex drive鈥�, I鈥檇 like to know about it. But so far we really don鈥檛 know.

Owen Holland

Robots are usually seen as the paradigm case of things which obviously don鈥檛 and can鈥檛 have free will. Industrial robots certainly are automata, but I want to turn this negative view around by talking about another kind of robot, the biologically inspired robot designed to imitate humans and animals or to have an architecture containing abstractions based on our understanding of humans or animals.

The first of this breed was devised in 1948 by Grey Walter, a pioneering neuroscientist. The way Walter described their design is critical to our understanding of what robots are: 鈥淥ne of the elements of animal behaviour and human psychology, which the [robot] tortoise is designed to illustrate, is the uncertainty, randomness, free will or independence so strikingly absent in most well-designed machines.鈥�

He discovered something else, too. People treat small robots physically as if they were small animals, and, importantly, they attribute to them intention, decision-making, moods. Fifty years on, the ease with which small robots encourage people to project animal qualities onto them has been exploited by large corporations 鈥� like Sony with its dog, Aibo.

And what about robots that mimic humans? The best known is Cindy Breazeal鈥檚 Kismet at MIT. This is a cartoon-like collection of plastic and metal in the form of a robotic head, with facial expressions, a voice of sorts, and head movements, all linked to a sophisticated internal model of emotion. Kismet is almost a caricature of a humanoid robot 鈥� but 鈥渟he鈥� produces interactions with humans that look and feel natural.

On the Web, there鈥檚 film showing a researcher who had worked in the lab for seven years, taking part in an exercise to 鈥渟cold鈥� Kismet 鈥� bad robot, no, inappropriate, bad! Kismet鈥檚 ears go down, her eyes go down, head goes down鈥� The researcher turns and looks at the camera, absolutely horrified at the idea of hurting the robot鈥檚 feelings! But don鈥檛 call this an illusion 鈥� some people maintain it鈥檚 the real thing, that鈥檚 all there is. Go to any bar at 1 am, where it鈥檚 too noisy to hear, and you鈥檒l see Kismet talking to Kismet鈥�

Now whatever consciousness is, it does appear to be some kind of user illusion created by the brain for dealing with itself. And while a lot of what consciousness seems to be telling us is wrong, it鈥檚 still very useful. In The Illusion of Conscious Will, Daniel Wegner extends this by arguing that conscious [free] will is an illusion that allows us to track and identify the 鈥渁uthorship鈥� of our actions, and to behave consistently. These illusions are engineering solutions from nature, to solve engineering problems which we don鈥檛 yet understand. But when our biologically inspired robots get sophisticated enough, we鈥檒l copy those tricks. So robots won鈥檛 have free will but they will have the illusion of it, the same illusion that we have.

As a roboticist, I鈥檒l settle for that. As a human being, I鈥檓 not so sure.

Geshe Tashi Tsering

In Buddhism, free will is not discussed. One of the main points in Buddhism 鈥� known as dependent arising, or dependent origination 鈥� is that everything and every event, including human existence, comes into existence dependent on others. My existence and your existence is dependent on others. So free will is not really discussed.

As a human being, my existence is a combination of material matter and consciousness. When this combination is put together, I can say I exist, I function. But if I search within this combination of matter and consciousness, can I find anything that I can describe as a 鈥渕e鈥� or an 鈥淚鈥�? No, I cannot find it. I am a process, a combination of mind and matter. If we go beyond that, and try to find something within it that we can call a 鈥渕e鈥� or 鈥淚鈥�, we cannot find it. Our feelings, such as of happiness of sorrow, also come into existence as a result of causes and conditions.

For me, free will seems very much connected with the concept of the god or the soul. But Buddhism doesn鈥檛 believe in that. There isn鈥檛 within ourselves something we can call a soul. Simply, everything comes into existence through causes and conditions. Given the right causes and conditions, things will come into existence, events will happen. But nothing exists independently, or inherently. Everything, including our identity, is dependent on others.

Simon Blackburn

Exercising the prerogative of the chair, I would say I agree with Shere Hite that talk of 鈥渄rives鈥� is often doubtful. It leads people to think that drives aim at their own extinction, which is a mistake. Sexual desire aims at sex, not at absence of desire.

Then I must say I agree with Geshe Tashi that the 鈥渋nterventionist鈥� idea of free will 鈥� that the real 鈥渕e鈥� can stick its finger in and change the direction of the body-brain mechanism 鈥� is untenable. It postulates a self as a kind of extra-physical 鈥渆xtra鈥�. And I was intrigued that Chris talked about neurophysiologists searching for the moment of freedom. That strikes me as reflecting the Cartesian or interventionist view.

Most philosophers think of free will more in terms of 鈥渞eason responsiveness鈥�. What it means to regard you as free, as opposed to being in the grip of some delirium or schizophrenia is that I expect you to respond to reason in a certain way: if you don鈥檛, then I don鈥檛 regard you as free and I think of you as a phenomenon to be managed or avoided like bad weather. This is the compatibilist idea of free will. There isn鈥檛 a moment of freedom, there鈥檚 just the ongoing fact about a person that they are or are not responsive to reason and so responsible for what they do.

Aaron Sloman

University of Birmingham

It hasn鈥檛 been said clearly enough that there are different interpretations of the phrase free will. I鈥檒l mention four: there are probably a lot more. There鈥檚 the theological notion, that it鈥檚 God鈥檚 excuse for the nastiness in the world 鈥� he didn鈥檛 do it, it was down to our free will. Another notion is the romantic one of people wanting to feel they鈥檙e initiators rather than products of things, and this often comes out in poetry and novels. Another is a legal and social idea and has to do with the conditions under which you can be punished, blamed or absolved of something you鈥檝e done.

Then there鈥檚 another notion waiting to be invented, which is the scientific version. Once upon a time, there were very simple organisms which unlike other physical objects had a store of chemical energy inside them which they could use to resist some external forces and to make selections between them. Gradually evolution found more and more sophisticated ways of building mechanisms that could enable these organisms to take information and use it later. To be like a human being you have to have a very large collection of different capabilities that were produced at different times in our evolution. Owen鈥檚 robots have a long way to go but there鈥檚 no reason why they shouldn鈥檛 get to the same state as us. Then they鈥檒l have what we have: the ability in some sense to control our own destiny instead of being subject to physical forces acting on us.

Christopher Cordess

University of Sheffield

It seems in much of this discussion there exists the notion of a subconscious or a pre-conscious or a not-so-very conscious, not necessarily in the Freudian sense. As a forensic psychiatrist I鈥檓 often trying to make a judgement about how responsible someone was for their action, and it鈥檚 evident that a rational choice model is inadequate, because the last person who knew what they were doing was the person doing it. One is then in the area of something pre-conscious or unwilled. This kind of thinking is certainly not amenable to the scientific interpretation we might like.