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Meat Thinks Sandra LaFave, Ph. D. Until a few hundred years ago, philosophers, especially rationalist philosophers, considered it IMPOSSIBLE that bodies (“meat”) could think. One obvious reason is that souls in heaven are typically portrayed as doing all kinds of conscious stuff – thinking, sensing, enjoying, etc. – while their bodies are obviously decaying. René Descartes (1596-1650), for example, did not think physical stuff could think. His view is known as substance dualism. Substance dualism is a metaphysical view: a view about what exists, has being, is real. It is also a view about what it means to be a person (“personhood”). According to substance dualism, only two kinds of things exist: • physical things (res extensa) and • non-physical “things” (res cogitans). A person comprises both kinds of being, although the body is temporary and disposable. According to substance dualism, the two kinds of being are completely different. Their properties are incompatible. See the handout for substance dualism’s descriptions of the properties of the two basic metaphysical categories. Note that “XOR” means exclusive OR. The logic expression “p XOR q” means that either p or q is the case but NOT BOTH. What's distinctive about Descartes’ substance dualism is the notion that Mental (capital “M”) substance (res cogitans) is necessary for mental states. We would probably want to say the brain is involved somehow, no? Descartes denies this. If something is Mental, it can’t also be physical. If something is physical, it can’t also be Mental. The Mental comprises all “invisible” events of consciousness including thoughts, intentions, desires, knowledge, and feelings. Only res cogitans can think, feel, and know. To sum up, according to the metaphysics of substance dualism, everything that exists is either • Res cogitans: thinking “substance” (rational, unlimited, dispassionate, orderly, logical, clean, “pure”, free, active, creative mind or soul or consciousness) – “soul”; XOR • Res extensa: extended substance (inert, passive, corruptible, possibly disgusting, predictable, decaying) – body. Note how the material/physical column describes the attributes of things in the world as described by science. Things and events in the physical world are able to be sensed, occur regularly, and can be predicted on the basis of scientific laws. Res extensa, for Descartes, is the world of determinism. If persons were merely material things, they would be objects in the universe and their movements in the world would be determined by the laws of science. They would not have free will. But free will is a fundamental Christian doctrine. The notion of free will underlies the notion of sin. No sin, no need for redemption from sin, no need for Jesus. Substance dualism – the idea that reality includes material and non-material – also has implications for epistemology. Epistemology is the branch of philosophy that concerns knowledge. What can res cogitans know with certainty? Only propositions like itself: propositions whose truth is independent of res extensa. For example, math truths are true whether or not res extensa exists. So is cogito ergo sum. Knowledge about res extensa is knowledge about the changing world of the senses, so in that sense, knowledge about the external world has to be inferior and unreliable. Knowledge about the realm of res cogitans is unchanging and universal, and thus absolutely reliable. This kind of knowledge is often called a priori knowledge, like knowledge of math and logic. Why substance dualism is attractive 1. It includes human freedom. 2. It makes humans and other rational beings unique and special – superior to mere things, able to use and command things. (Remember the Church condemned Galileo for daring to say the Earth was not the center of the universe.) 3. Res cogitans can survive the dissolution and death of res extensa, so people survive death. As Plato put it, “The soul of man is immortal and imperishable.” Descartes’ project in the Meditations The full title of the work? Meditations on First Philosophy in which are demonstrated the existence of God and the distinction between the human soul and body Descartes wrote the Meditations to satisfy the Church that it had nothing to fear from the new science. So Descartes is careful not to challenge ideas important to the Church, such as free will and the existence of immortal souls. In fact, he gives arguments for those views. At the time Descartes was writing, scientists had already found what seemed to be (and was) very reliable knowledge about res externa, particularly in astronomy. Scientists, including Descartes, wanted the Church not to persecute them, and hopefully, to accept that science has an important role to play in the world. The Church, for its part, wanted scientists not to interfere in its role as the ultimate moral authority. Science per se didn’t threaten the Church as long as science talked only about res extensa: in other words, as long as science kept silent about conscience or religious or moral belief. Descartes found a clever way of reconciling the Church to science. He noted that if God is not a deceiver, the objects of math knowledge appear to be unchanging universals, so if God is not a deceiver, res cogitans knows math with absolute certainty. However, math was also the language of science. But the scientists’ mathematical (a priori) knowledge of the world was drawn from unreliable changing sense data -- i.e., from res extensa. Descartes wants to show that math knowledge about res extensa is really reliable (Descartes’ own work on optics was on the line), without scaring or offending the Church. Does anyone know Descartes’ solution? HINT: it’s in the title of the Meditations. Meditations on First Philosophy in which are demonstrated the existence of God and the distinction between the human soul and body Descartes’ strategy may strike you as lame, but here it is: (1) Demonstrate in a way that convinces any rational person (even scientists) that God exists and is not a deceiver. Descartes uses a traditional argument for God (the Ontological Argument) that supposedly does not involve any reference to res externa. This is a whole other talk. Let’s just note that philosophers have a lot of issues with the Ontological Argument. (2) Recommend to the Church that because God exists and is not a deceiver, scientists should not be prevented from using math confidently in their investigations of the physical world. Whether they know it or not, scientists depend on God for the legitimacy of their conclusions about the external world. Furthermore, since res cogitans cannot be an object of scientific study – since it is still private and unobservable – scientists can have nothing to say about it. Science rules in the realm of the physical. The Church rules in the realm of the spiritual. Interestingly, the Catholic Church has pretty much stayed out of science’s way since Descartes, so his strategy worked. Too bad substance dualism has so many problems. Philosophical Arguments Against Substance Dualism Objection 1: The most obvious problem is that substance dualism appears to fly in the facts of our ordinary experience of our bodies and our consciousness (res cogitans). If mind and body are completely separate kinds of being, why does consciousness change when I put LSD into my body? Why do people with brain damage (e.g., people with Alzheimer’s disease) have any loss of normal consciousness? Objection 1 exemplifies what philosophers call the mind-body problem. If substance dualism is true, the two kinds of reality are totally sealed off from each other: res extensa can’t influence res cogitans, and res cogitans can’t influence res extensa. Yet as we have seen, the two kinds of being appear to interact all the time. How do you move your arm, for example? You might say that first you think about moving your arm. Your res cogitans does the thinking, according to substance dualism. Now, res cogitans is not part of the physical world. And things in the physical world move only by the agency of other things in the physical world. So how exactly does your thought of moving your arm result in your arm moving? Descartes knew, of course, that there was interaction between mind and body. Descartes says, “I [presumably his res cogitans] am not only lodged in my body as a pilot in a vessel, but … I am very closely united to it, and so to speak so intermingled with it that I seem to compose with it one whole.” Examples: If I hit my hand with a hammer, I am conscious of pain (body influences mind). I feel the pain of the hammer immediately, without having to call in res cogitans. If I remember that my Mom’s birthday is today, I will pick up the phone and call her (mind influences body). Descartes needs to explain how this is possible. His response is disappointing, though. In Passions of the Soul, he writes “I had clearly ascertained that the part of the body in which the soul exercises its functions immediately is in nowise the heart, nor the whole of the brain, but merely the most inward of all its parts, to wit, a certain very small gland which is situated in the middle of its substance …” (the pineal gland, in the mid-brain) Wait a minute … didn’t he say mind can’t be located? Descartes’ “solution”: the pineal gland is the “locus of interaction” where the mental can interact with the physical. Malebranche’s “solution”: Although God is res cogitans, God can do anything, including move bodies. So you might think you’re moving your arm, but it’s really God. Neither of these solutions are adequate. Objection 2: The Mental is defined only in terms of what it is not. Generally, negative definitions are far too vague to be useful. How many zillion things are contained in the set of “not-pencils”? Objection 3: The notion of res cogitans is compatible with all states of affairs. If a claim is compatible with all states of affairs, the claim can’t be proved true or false. Consider the following statements: (1) “Sandy LaFave is in this room.” (2) “Barack Obama is in this room.” (3) “God is in this room.” Statement (1) is true, because it corresponds to what is so. Statement (2) is false, because it does not correspond to what is so. We know how the room would be different if Obama were here. Statement (3) is neither, because we don’t know how to determine whether the state of affairs expressed is the case. We don’t know how the room would be different if God were here (assuming the ordinary notion of God as an invisible being). Scientists are wary of statements that can’t be proved true or false. You find statements compatible with all states of affairs in astrology and pseudo-science. Examples: (1) “The universe came into being this morning, complete with so-called “historical” records and so-called “memories”.” (2) Your horoscope of the day: e.g., “You may be disappointed today.” The claim that “res cogitans exists” is similar. The very definition of res cogitans guarantees that you won’t be able to tell if it’s around, since it’s supposedly unable to be sensed by bodily organs, invisible, outside of space and time, etc. Objection 4: Substance dualism commits the fallacy of composition. What’s true of the parts isn’t necessarily true of the whole. Consider this fallacious argument: All the atoms comprising this desk are mostly empty space. Therefore, this desk isn’t solid at all; it’s mostly empty space. The argument is fallacious because the arguer assumes (wrongly) that whatever is true of the parts of the desk (the atoms) must be true of the desk. BUT … The parts of a thing often have quite different properties from the whole thing. A whole thing often has different properties from its parts. Another example of the fallacy: The Philosophy Club is more than 30 years old. Therefore, every member of the club is more than 30 years old. (True premise, false conclusion = bad logic) Another (important) example: No cell of the body is conscious. Therefore, no body is conscious. The conclusion here does not follow from the premise. Objection 5: We don’t need res cogitans to explain consciousness and mental events. Consciousness is an emergent property of brains. Mental events are brain events. Wetness is an emergent property of water. Consciousness is an emergent property of brains. Ockham’s razor says “Do not multiply entities unnecessarily.” So if the notion of res cogitans is so problematic -- it gives rise to the mind-body problem, its existence can’t be verified or falsified, it is defined only by negation, it is not needed to explain consciousness, etc., -- then according to Ockham’s razor, we should probably remove res cogitans from our metaphysics. Translation: give up the idea of spiritual substance. Substance dualism also contributes to confusion and unsavory consequences in two other ways: (1) In epistemology, substance dualism helps contribute to serious misunderstandings of subjectivity and objectivity. (2) Substance dualism supports traditional misogyny and speciesism. (1) In epistemology, substance dualism helps contribute to serious misunderstandings of subjectivity and objectivity. Substance dualism has contributed to the mistaken idea that “Objective” and “Subjective” are mutually exclusive (the XOR). In science, “OBJECTIVE” goes with “public” “physical” “measurable”. “SUBJECTIVE” goes with “private” “mental” “not measurable”. Epistemologically for rationalists like Descartes and Plato, what happens “inside” the private conscious self (feelings, emotions, intentions, thoughts) is forever private, since everything is either res extensa or res cogitans and never both. No one can ever feel your pain, for example. And epistemologically, the notion of “opinion” – subject to change and improvement – goes with res extensa: the changing world of the body and the senses. So, if you have a headache, according to substance dualism, your headache is an experience of res cogitans (consciousness), so it is “subjective” “invisible” “private” and in fact cannot be known to exist in the physical world, because there are only two mutually exclusive ways to be in the world: either res extensa XOR res cogitans (and not both). This is odd, no? We do think headaches are felt AND are also events in the physical world. People go to doctors every day for pain relief. It can get odder. You might apply this very same reasoning to your experience of the Eiffel Tower. There you are in Paris, looking at the Eiffel Tower, and you think, "Gee, no one else is having this precise experience of the Eiffel Tower, it’s my private experience, so this experience of mine is just as subjective as my headache!“ And if you are philosophically inclined (and philosophically naïve), you might go further and make an argument like this: P1: All my experiences of res extensa (the world) are unique and private to me, i.e., they are all “subjective”. P2: “Subjective” is the XOR opposite of “objective”. P3: If all my experiences are subjective, then whatever I say about them has to be mere belief or opinion. P4: P1 and P3 are true of everyone! C: Nobody can be objective about res extensa. Anything anyone says is “just their opinion”. But (as Plato liked to argue), not all opinions are equally valuable. Some people’s opinions are nonsense. (2) Substance dualism helps support traditional misogyny and speciesism. Terry Bisson’s story They’re Made of Meat The aliens in the story are OK with the idea that meat can think. “The brain does the thinking. The meat.” In fact, most contemporary philosophers would agree with the aliens. So if the issue is not substance dualism, what is it? Historically (and even today in many cultures) people have denigrated the body, sexuality, and bodily pleasure because the body is supposedly the dirty disposable inferior part of a real person, and a major source of temptation to sin. Furthermore, cultures commonly identify the mind with the Male (he is rational, active, objective, logical, strong-willed) and the body with the Female (she is emotional, passionate, weak-willed, passive, and in need of the guidance of the man). Western cultures have historically withheld personhood from many people. Females have not had the status of full persons in many cultures. The same goes for lower-status men. Western cultures still withhold personhood from big-brained social animals (chimps, dolphins, elephants, whales, etc.) and Artificial Intelligences (AIs). Since we do not know what extraterrestrial life forms might look like, humans will need to think carefully about which alien life forms should be treated as persons and which are expendable/edible. Since in substance dualism, the res cogitans is the real person, identifying res cogitans with the Male in effect denies genuine personhood to females, lower-status men, children, bigbrained social animals, and AIs. Descartes, for example, thought animals did not have consciousness. And because substance dualism’s has only two mutually exclusive metaphysical categories, not a full person means not a person at all. Many entities are consigned to the status of Other, permanently and with no appeal. And if you are Other – res extensa – you are just a thing. You are made to serve the highstatus Male, who can use you with impunity. You might even be a source of disgust, like … meat. The aliens represent the dilemma facing humans qua res cogitans in encountering unusual life forms (e.g., aliens and AIs): how to decide who counts as worthy of respect, and who is Other. And unfortunately, the aliens in the story handle this human dilemma in a typically clumsy human way: arbitrarily, irrationally. The aliens think humans are meat, meat thinks, and meat is simply disgusting. Notice their disgust is not based on reasons; it is visceral and primitive. The aliens know that mere disgust is not a good enough reason to ignore the signals, yet they decide to ignore the signals anyway, and thereby violate their own official rules. They demonstrate, for me, the ambivalence towards the “lower” body/Other that has historically gone hand in hand with substance dualism. This ambivalence towards Others – those whose full personhood is in question – seems to me a prominent theme in popular culture. For example, story lines about ETs and AIs are commonplace, and a recurring theme is “You can’t deny respect and rights to [fill in the blank] just because [fill in the blank] is from another planet, or happens to be a sentient robot.” The world of Star Wars has that problem licked.