2 Kinds of minds

Let us then start on the questions of what kinds of things possess or could possess mentality, while remembering that the meaning of the term is somewhat elastic and imprecise.

At the outset we proceeded as if creatures with mentality were a sub-category of living creatures – Aristotle certainly thought this – and mentioned both human and non-human animals as examples. However, in answering the above question, you might have wondered whether it is possible for a machine to have a mind or some kind of mentality. If so, you are in good company, for some cognitive scientists are willing to ascribe beliefs to such lowly machines as thermostats! The philosopher John Searle reports John McCarthy, one of the founders of the field of ‘artificial intelligence’, as saying that ‘machines as simple as thermostats can be said to have beliefs’. Searle asked McCarthy what beliefs his thermostats had, and McCarthy answered: ‘My thermostat has three beliefs. My thermostat believes – it's too hot in here, it's too cold in here and it's just right in here (Searle 1984, p.30). This probably seems preposterous, an extreme and egregious case of anthropomorphising which is hard to take seriously. But what about more complex machines, such as computers and robots? Not just today's computers and robots, but also tomorrow's. One line of thought infused in popular culture is the idea that while a robot or computer, built entirely out of non-organic parts, could engage in much of the kind of thinking and reasoning we engage in – indeed, it might even be superior to us in this regard – it could never have a full-blown conscious mental life like ours. It might even be able to have limited visual, auditory and tactile perceptual capacities, in the sense of being able to discriminate accurately among various colours, shapes, sounds and surfaces. But surely no machine could ever experience pain, for example, by touching a burning hot surface, even though it might be able to detect bodily damage to itself caused by touching a hot surface. Moreover, no mere machine could feel emotions like love or jealousy or embarrassment. And even when it comes to perceiving, we are tempted toward scepticism about whether a machine that could detect the presence of coffee or chocolate would really be having any accompanying olfactory and gustatory experiences. Indeed, the plots of some science-fiction stories revolve around certain robots and computers, which are superior to humans in certain cognitive tasks, lacking the full range of human experiences. The robot or android Data in the television series Star Trek: The Next Generation is an example. As viewers well know, various comic moments are created by Data's superior intelligence and rationality but absence of emotions. Moreover, it is often said that even the most complex machine is in principle incapable of imagination and creativity: a computer, for example, could never invent anything or produce a work of art. It is not entirely clear why this should be so, but one thought appears to be that machines are governed by strict deterministic principles and creativity and imagination involve the free play of the mind unrestrained by any algorithmic bounds. But how do we know that our minds do not run according to strict deterministic principles?

Another line of thought present in popular culture is that, one day, computers may even be able to have experiences, emotions and creativity. The evil supercomputer HAL 9000, for example, in Stanley Kubrick's film 2001: A Space Odyssey famously exhibits emotions when he is being ‘shut down’ after murdering some of the human crew of a spaceship. The android Data learns to play the violin and paint. The robot C3PO in the Star Wars films exhibits emotions like fear, worry and frustration; though it is not clear whether he is capable of feeling physical pain. The robots or ‘replicants’ in Ridley Scott's film Blade Runner can feel pain and start to develop emotions after building up a bank of life experiences – with disastrous results. Interestingly, however, these ‘replicants’ are made out of organic materials, they are biological robots, and are only distinguishable from humans by sophisticated tests. Nevertheless, it is clear that even according to this line of thought, there is supposed to be something more amazing or surprising about an emotional or creative robot than there is about a pure thinking or calculating robot. This is no doubt owed partly to the fact that we already have computers that can perform astonishing feats of calculation – witness the fact that the computer Deep Blue has beaten the world chess champion Gary Kasparov – but there is no mechanical device that exhibits even a modicum of the affective side of mental life.

Machines are not the only kinds of non-living, non-organic creatures that are often said to have minds. According to the Christian religion, angels exist and have minds of some kind, as does God, if He exists. What is the mind of an angelic being like? It depends, first of all, on whether angelic beings have material bodies, for we need to know whether they have any sense organs. Opinions about this differ in much the same way as opinions about the nature of the soul differ. Consider, for a moment, the different views about the nature of the soul. Sometimes the soul is thought of as a particularly fine or rarefied material substance with a vaguely humanoid shape. Thus, in the Iliad the souls of the dead Homeric heroes are their ‘life forces’ and are associated with their breath. The souls leave their dead bodies when they heave their last breath and descend to Hades to live out a bleak and shadowy existence. At one point in the Odyssey, Odysseus descends to Hades to consult the ghost of the blind prophet Tiresias, with whom he speaks for some time. There is also a tendency to think of souls as completely immaterial substances, with no shape, mass, volume or spatial dimensions at all; not the kinds of things that can be seen or sensed in any way, let alone conversed with, except perhaps under very special circumstances. Returning to angels, St Augustine (354–430) claimed that we do not know whether they have material bodies, and Descartes, at least at one point, thought that ‘it is not clear by natural reason alone whether angels are created in the form of minds distinct from matter, or in the form of minds united to matter’ (Descartes 1985, vol. III, p. 380). According to Aquinas and Roman Catholic doctrine, however, angels are purely spiritual beings with no material bodies. But as the literary critic Harold Bloom (1997) points out, in Paradise Lost Milton portrays the angels as embodied beings eating human food. And anyone who has seen western religious art (such as romanesque mosaics, gothic icons and Renaissance paintings) is familiar with angels with wings, faces, hands and feet, wearing robes and holding swords and flowers and playing musical instruments. Similar descriptions of angels can be found in the Bible. Perhaps, of course, these are all anthropomorphic metaphors consistent with the literal immateriality of angels.

Leaving angelology to one side, the important point for present purposes is that if angels have no material bodies then they have no sense organs. Since they have no eyes or ears or noses, it seems that they cannot perceive the world in any way similar to us earthly mortals. For certain followers of Aristotle, such as Aquinas and other medieval scholastics, angels did not even have the power of imagination, for they thought imagination, like sensation, is a bodily process. On this immaterialist interpretation of the angelic mind, angels are pure rational intellects whose minds are devoid of all sensuous experience; or at least they are so until they descend to earth to communicate with humans, at which point perhaps they become able to receive and process streams of sensory information by being temporarily attached or ‘housed’ in a material body. Indeed, according to scholastic theological tradition, since angels do not have bodies they must borrow unused ones in order to deliver messages to earth. It is important to realise just how puzzling the nature of such a mind would be if there were such a thing. Is an angelic mind like the mind of a creature all of whose sense organs have completely ceased to function, which are ‘turned off’ either permanently or from time to time, who enters and exits states of total sensory deprivation, like a more extreme version of Helen Keller, who lost both sight and hearing at a very early age?

It is not clear that this is the right way to think about it. After all, angelic minds, according to the immaterialist interpretation, are not only ones that never or rarely have sensory experiences; they were never supposed to have any sensory experiences in the first place, for it is simply not part of their nature to do so. Add to this Aquinas's view that angels do not even use language, except when communicating with humans and things become even more unfathomable. What would such a pure intelligence be like? Is it a completely different type of mentality, so utterly foreign to us that we cannot even imagine what it would be like? And what is it like when an angel, on an earthly mission, becomes temporarily embodied? Does it experience full-blown sensory awareness or is its experience flattened out and ‘flavourless’, a deprived form of our own? The latter option is explored in Wim Wenders's film Wings of Desire, in which an angel faces the dilemma of having eternal life without sensuous experience or a mortal life overflowing with it. His desire to experience human feelings and sensations is so strong that he chooses to renounce his angelhood and accept the inevitability of death. His first course of action with his new mortal coil is to drink a cup of black coffee, which he thoroughly relishes. In contrast, Descartes appears to have thought, despite the apparent agnosticism of the previous quotation, that the mental life of a temporarily embodied angel would have no sensuous phenomenological dimension at all; it would have no sensory experience but would simply make intellectual judgements about the state of its borrowed body. As he said in one of his letters explaining how mind and body are related in humans: ‘if an angel were in a human body, he would not have sensations as we do, but would simply perceive the motions which were caused by external objects, and in this would differ from a real man’ (Descartes 1985, vol. III, p. 206). Interestingly, in his essay ‘The Disembodied Woman’, the neurologist Oliver Sacks (1986) describes a case of someone approaching this condition. Owing to severe inflammation of her nerves the eponymous patient loses her proprioception, her inner sense of the position of her body and limbs – her ‘body image’ – and has to rely entirely on her visual perception of them in order to perform even the most daily of tasks, such as sitting, standing, walking and eating, things which most people can do with their eyes closed. There is a bewildering variety of views, in both intellectual history and the popular imagination, about the kinds of minds that exist or that could exist and little agreement about what these minds might be like.