I: Context in MATSEC AM 25: Module 3, Question 3

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1 I: Context in MATSEC AM 25: Module 3, Question 3 The question we will be addressing here, how do I know? is one out of four in module 3, which alone makes up the second paper out of two. In the MATSEC A level. Module 3, Key Questions in European Thought, is the additional part of the syllabus that only advanced students cover; intermediate students only do logic and ethics. Paper two includes a compulsory gobbet question which could be taken out of any of the selected readings for module 3. The other two questions are selected from five, and could cover any of the 4 topics of module 3; i.e. the self or soul, the problems of evil and the free will, the problem of knowledge (epistemology), or language. For this question, the readings are mostly from Descartes, Locke and Hume, i.e. the modern period, although there is also a contemporary extract from Searle. Syllabus: Module 1: Logic and Reasoning Module 2: Theoretical and Applied Ethics Paper 1 (3 hours) Module 3: Key Questions in European Thought 1. What am I? Plato, Aristotle 2. Do we live in the best of all possible worlds? Stoics, Augustine, Aquinas Paper 2 (3 hours) 3. How do I know? Descartes, Locke, Hume 4. How can we communicate what we mean? Readings: (a) Descartes, R. Meditations, I and II. (b) Locke, J. Essay Concerning Human Understanding in Stumpf, pp (c) Hume, D. A Treatise on Human Nature, bk. 1, part 1, sect. 1 (c) Searle, J. The Mind-Body Problem: A Contemporary View in Stumpf, pp Recommended Texts: Stumpf, E.S., Philosophy, History and Problems (New York: McGraw-Hill, Inc., 2011) Lacewing, M., Philosophy for AS (London: Routledge, 2008) Colette Sciberras, PhD (Dunelm)

2 II: Historical Context: The Scientific Revolution and the Rise of Modern Philosophy The Scientific Revolution is the name for that period in history where a new method for discovering knowledge was being defined. It is generally held to have begun around 1550 with Copernicus and ended around 1770 with Newton, by which time the scientific method was established. The modern scientific method was different from the traditional, medieval way of learning in several ways: Firstly, it is undogmatic. In the Middle Ages, and even today in cultures where ecclesiastical authorities are responsible for education, scholars mostly limited themselves to reciting revered texts by heart. The words of the wise ancients were taken to be final on all matters. What sets the modern period apart from the medieval, in our context, is that scholars became increasingly able to contradict the traditional texts of Christendom, i.e. the Bible, Plato and Aristotle. Christian Theology had been highly influenced by classical Greek thought, and medieval philosopher theologians such as St. Augustine and St. Aquinas continued in the tradition of Plato and Aristotle respectively. At the time, it was assumed that if a hypothesis contradicted the Bible or Aristotle then it must be wrong (Plato was not held to be infallible in the same way). The scientific revolution slowly changed that. Although Copernicus risked getting into trouble with Christian authorities, and Galileo was even jailed for publishing his ideas, eventually science would extricate itself altogether from theology and become the independent search for knowledge, with its own criteria of truth, which we know today. Still, Plato and Aristotle were highly influential in the development of modern philosophy, which is said to have begun with Descartes in the early 1600s. Although the Copernican Revolution was a revolution against Aristotle, he and Plato inspired the two main schools of thought within modern epistemology, namely empiricism and rationalism respectively. Plato s concern with Ideas (Forms - Gk: eidos) at the expense of his interest in the material world, as well as his scepticism regarding the latter, were inherited by rationalists such as Descartes. Rationalists also value arithmetic and geometry as examples of rational disciplines, in that the truth of their axioms and proofs can be seen as self-evident and rationally intuited. In Meno, Plato uses geometry as an example of how some knowledge is innate, and can be drawn out of a mind through recollection. Descartes thought mathematical truths like = 4 are truths that can only be doubted if the creator of the world and our minds was not a benevolent God, but an evil demon. Aristotle s interest in the material world, his emphasis that form (morphe) only resides in matter (hyle) similarly inspired the empiricists, who would start to look for proof of their theories in the material world as well as in the axioms and proofs of rational thought. Descartes defined matter as that which has extension, that is, a size, shape, and position in time and space. Things that have extension can be measured, and thus empiricists emphasize a need for empirical evidence based on Colette Sciberras, PhD (Dunelm)

3 sense observation in terms that can be quantified, measured and verified by others. Properties that could be reduced to numbers are ideal objects of scientific study as they can be verified objectively. The ideal sciences were physics and chemistry. The Scientific Revolution is best known through certain key events, some of which might be modern myths. Galileo is known for having built a telescope and discovering the moons of Jupiter, the phases of Venus, having discovered mountains on the moon, and witnessing a supernova. These observations clearly contradicted Aristotle s claim that celestial bodies were perfect spheres, and that above the level of the moon, the heavens were immutable. Galileo is said to have invited members of the church, who did not want to accept these facts, to look through the telescope for themselves. He performed experiments with inclined planes, pendula, and famously, is supposed to have attracted a lot of attention dropping balls of different weights from the tower of Pisa in order to disprove Aristotle s theory that the heavier one would hit the floor first. In short, Galileo emphasised the necessity of empirical observation and experimentation. It is not enough for scientists to make observations and collect evidence, however; science also needs to order these into a theory or hypothesis that can be tested. The experiments Galileo performed on inclined planes, for instance, led to his discovery that the ratio of the distances traversed by the ball is proportional to the ratio of the squares of the time, and permitted him to calculate gravitational acceleration (g-force). Therefore the characteristics of the new science which was defined during the scientific revolution and through the rise of modern philosophy are: 1. It is undogmatic 2. It emphasises sense experience and empirical observation 3. It aims at mathematical certainty by quantifying phenomena and seeking the principles and laws of nature Plato and Aristotle had great influence on modern epistemology, as we have seen, in that while they were both explicitly rejected by the founders of modern science, at the same time the issues that Aristotle had with Plato s theory of Forms provide an ancient model for the disagreements between empiricists and rationalists. It is however, incorrect, strictly, to refer to Plato and Aristotle as rationalists or empiricists, simply because these words are used to refer to two modern traditions in philosophy. This is especially true of Aristotle, since the modern empiricists used the emphasis on experience and quantifiability to argue against Aristotle s philosophy of formal and final causation. The successes of Galileo and Newton, among others, led many modern philosophers to believe that: 1) Nature is made up of nothing but matter-in-motion. One of the strengths of science is that it discovers laws which describe phenomena precisely. It is believed that similar laws can be discovered to describe every aspect of nature, including human behaviour, which is therefore determined and predictable. This view is known as mechanism. One of the implications of mechanism is that there is nothing mysterious about life or the mind; certainly there is no special consciousness substance, no soul or life principle or anything non- Colette Sciberras, PhD (Dunelm)

4 material, except, possibly, in God and his special creation, humans. This philosophy is called materialism or physicalism. Many modern philosophers adopted a mechanist view about all of non-human nature, but reserved a special soul for humans, and conceived of God as a different substance altogether. Descartes s definition of God, his dualism about mind and body and view of animals as automata, is an example of such a position. Other philosophers, such as Hobbes, adopted a universal mechanist approach, to describe even human thoughts, actions, societies, and so on. 2) Appearances sometimes deceive. For example, the sun seems to rise and set, but in fact it does not move, the earth does. When one drops two objects, it seems like the heavier one should always hit the floor first, but this is not so. Thus scientists and philosophers from Galileo onwards would distinguish between I. The primary properties of a thing - e.g. its mass, size, and velocity and anything which can be measured and is therefore objective. II. Secondary properties, or the way a thing appears to us - e.g. colour, beauty, and our values regarding what should or should not be. Anything which is subjective is considered outside the scope of science. 3) Anthropocentrism may be false. Even if God did create the universe, there seems to be no need to refer to that fact to explain how nature works. Moreover, the discovery that our earth is just a planet orbiting a star, and not the centre of the universe as Aristotle had thought, makes it less likely that we are God s special creatures. Non-anthropocentrism, the idea that humans are not at the centre of the universe, finds its roots in the scientific revolution and would be complete when Darwin showed that humans are just another species on earth, descended from apes. The Scientific Revolution thus brought about a complete overhaul in Western thought and marks the beginning of Modern Philosophy, in which epistemology, the study of knowledge, takes central place. As we have seen, the philosophers and scientists of this time were concerned with outlining a new method for science, and among their first concerns were the questions what counts as knowledge, how can we be certain of anything, and what is the best way of reaching such certainty? In our syllabus, the question is given as How do I know? Read more: Copernicus Galileo Scientific Method III: Ways of knowing and types of truth Epistemology is not concerned with knowledge of how to do something, e.g. riding a bike, or with acquaintance knowledge, e.g. knowing the people next door. Colette Sciberras, PhD (Dunelm)

5 The only kind of knowledge we are interested in is knowledge of facts or propositional knowledge. Propositional knowledge is the kind of knowledge that can be expressed as I know that (p) where (p) stands for any proposition describing a (putative) fact. In philosophy, knowledge is defined as justified true belief. That is, in order to say that we know something, for example that it rained last night, first of all we have to believe that it rained last night, but of course this is not enough. Our belief must be: 1. True. That means, if it turns out I was wrong, that it didn t rain last night, I cannot say that I knew it rained last night. One cannot know something which is not true, one can only believe it. 2. Justified. It is not enough merely to believe something which happens to be true; one needs to have good reasons for believing it, some kind of evidence, support or justification. The best kind of evidence for our example is empirical evidence; for example, I myself saw or heard the rain last night. Another type of proof is mathematical proof. Sometimes we may say that we know something, even though we cannot immediately explain how. When there is no empirical evidence, we say we intuit such truths. Intuition can be of two types. There is a spooky kind of intuition that is not usually of concern to philosophers; this is the kind of intuition that, for example, makes you claim that you knew the telephone was going to ring just then. Because we have no idea how we come to know such things, these experiences are not justified beliefs, even if true, and are not counted as knowledge defined above. They therefore do not feature in epistemology. Rational Intuition involves a similar kind of seeing or knowing, but if we think about it, we can find some kind of justification based on reason. For example: 1. (a) All men are mortal (b) Socrates is a man (c) Therefore Socrates is mortal = 4 In the first example, it seems obvious to us that if the premises (a) and (b) are true, the conclusion (c) must also be true. Thus we can rationally intuit that the argument is valid. Rational intuition, therefore, is seeing the truth of a claim by thinking about it. If pressed we could explain our reasons, in this case perhaps by drawing a truth-table, a diagram or in terms of set theory. However the experience of understanding the argument s validity, that is, our rational intuition, is enough to make us know that we know something, without us having to explain why. The argument in 1 is a deductive argument, where the truth of the conclusion necessarily follows from the truth of the premises. Deductive arguments, when valid and sound, provide rock-solid conclusions; however, because one of their premises is normally analytic (see below), these conclusions are not usually very interesting. Example 2 seems obviously and necessarily true even if we cannot explain how we know it. Moreover, it seems impossible to us that could ever make anything other than 4. Examples Colette Sciberras, PhD (Dunelm)

6 such as these are often used in philosophy. Those who emphasize reason, such as Plato and the rationalists, think that such understanding is innate in us. Famously, Plato had shown how the son of a slave could also perform arithmetic and geometry without ever having studied them. Empiricists like John Locke disagree. For them, a child can learn that = 4 only through experience, i.e. by learning it at school. The next distinction is between necessary and contingent truth. A contingent truth is a proposition which just happens to be true. For example, it rained last night happens to be true today, as I write these notes, but may be false on the day you read it. Its truth depends on circumstances, or on the state of the world. If the proposition corresponds with the facts, then the proposition is true. A necessary truth on the other hand is one that can never be false, like 2 +2 = 4. Sometimes these propositions turn out to be tautologies, in the sense that they are merely repeating the same concept twice. For example, all bachelors are unmarried is a necessary and tautological truth. The truth-table of a necessarily true proposition has a T in all its interpretations; under no circumstance can it be false. Therefore, this is one of the strongest criteria of truth that can be demanded. Often, necessary truths and tautologies turn out to be analytic propositions. Analysis is the process of understanding things through breaking them up into smaller parts. Analysis works on the assumption that if we can break something down into its elements, or its fundamental building blocks, we can understand better what it is. For example, when we analyse water, we find it is Hydrogen and Oxygen, and our scientific understanding grows. Similarly, Freud wanted to understand minds through analysis. An analytic proposition is one whose truth can be determined by analysing the meaning of its words. Hume described this type of knowledge as being based on the relation of ideas. For example, all bachelors are unmarried is clearly true, and to discover this truth, we don t have to carry out surveys or empirical studies of bachelors. The fact that they are unmarried can be known if one understands the meaning of the word bachelor. In other words, the idea of bachelor is related to the idea of being unmarried in that one is contained in the other. If we analyse our words, we will see that the statement is necessarily true. One of the most important questions in epistemology is whether there are any necessary truths with are not tautological or analytic. Descartes believed he had found one when he argued, I think, therefore I am. A proposition which is not analytic is synthetic. Synthesis is the process of putting two or more things together. For example, synthetic drugs are put together in laboratories using various substances. A synthetic proposition therefore combines two or more ideas. Importantly, these ideas cannot be derived from the meaning of any of the words used. For example, in the proposition Bachelors have more money and time, having money and time is not a concept that necessarily relates to bachelors. If the proposition is true, it is true in virtue of the way the world is and not the meaning of its words. Hume referred to these types of propositions as being about matters of fact. Thus synthetic propositions usually need empirical evidence to be verified. Colette Sciberras, PhD (Dunelm)

7 This brings us to our final distinction. Most synthetic propositions, because they require empirical verification, are a posteriori truths, if they are true at all. A posteriori concepts, truths and propositions are those that can only be known or verified through sense experience. A priori concepts, truths and propositions, on the other hand, are those which do not require sense experience or empirical verification. Analytic propositions and tautologies fall among these of course. All innate ideas, if any exist, are a priori too. The problem with analytic truths is that they rarely tell us anything very interesting about the world, but only seem to tell us about our own words and ideas. Analysing words does not seem to be a very promising approach to discovering new facts about the world. On the other hand, sense observation is fallible, and relying on it cannot give us the sense of certainty that necessary, a priori truths provide. Thus, one of the main questions in epistemology is whether there are such things as synthetic a priori truths and propositions, that is, sentences that tell us something new about the world, but which we can know or verify through reason, rather than empirical studies. IV: Main Theories in Epistemology - Rationalism and Empiricism Our question, how do I know? has been answered in two ways in the history of modern philosophy. Broadly, the two main theories of knowledge are: Empiricism: the theory that sense experience is the ultimate source of all our concepts and knowledge. Rationalism: the claim that that there are important ways in which knowledge is gained independently of sense experience. 1 Please note that as defined, it is inconsistent to claim to support both empiricism and rationalism. As Aristotle s square of logical opposition shows, the claims all knowledge is gained from the senses and some knowledge is not gained from the senses are contradictory, and as the truth-table of a contradiction shows, such statements when combined are always false! If you think that both empirical evidence and rational intuition are important ways of gaining knowledge, then you are probably a rationalist. If you also think that the ideas of maths, geometry and logic ultimately came to us through sense experience, then you are an empiricist. To think about the issue, ask yourself what a feral child can learn in the forest, without contact from other human beings. Could two feral children develop a way of communicating? Can they count up to three say? If so this would suggest language and numbers are innate. These are issues taken up again in question 4 of module 3; how do we communicate? 1 Both definitions are from Stanford Encyclopaedia of Philosophy Colette Sciberras, PhD (Dunelm)

8 Another way of explaining the issue of epistemology is that rationalists claim we can have synthetic a priori knowledge of how the world is outside our minds while empiricists deny this. (Lacewing 2008, 10) The clause outside our minds is an important one. As we shall see, both empiricists and rationalists agree that while appearances may deceive, the way they appear to us is a fact that cannot be doubted by me, even if it cannot be verified by others. To take an example, 2 if I catch sight of something which I think is a snake, but which in fact is a rope, it is also a fact that what I saw looked like a snake to me at the time, even if, later when I or others look at the rope, no one else sees anything like a snake. I cannot doubt the way things appear to me, and I cannot doubt anything that goes on in my consciousness, even if I can doubt its correspondence with the facts about the external world. This direct experience that one has of one s own mind is the crux of Descartes s argument. Scientists tend to downplay the importance of direct observation of one s mind, preferring to concentrate on phenomena which can be observed and verified by others. For rationalists, on the other hand, the mind is real, and the discovery that it exists is an important synthetic fact about the world, a fact which is known a priori. I think, therefore I exist (as a thinking being) tells us something about the world outside our minds. Descartes is not just aware that there is doubting going on in his mind. From that doubting, he infers the necessary existence of his mind, the existence of God and of external reality. Hume, an empiricist, would demand evidence of the existence of the self, mind, or soul, or whatever the substance is which is supposedly doing the thinking. It is not enough to say we have a clear and distinct idea of these, and to argue that, because we have no empirical evidence of God, say, the idea of God must be innate. Perhaps the ideas we rely on to think, such as substance, or cause and effect, are simply mistaken. Thus Hume s moderate scepticism differs from Descartes s whose methodical scepticism consisted of using doubt itself as a foundation for the discovery (or some may say construction) of necessary truths. In short, the issue between rationalists and empiricists is whether all our knowledge ultimately comes from the five senses, as the empiricists claim, or whether some of it comes from the mind or reason itself, hence rationalism. Rationalists extol the virtues of rational intuition and deduction, and emphasize mathematical certainty, dialectic, and the rules of logic. Of course, empiricists do not deny that people use reason to gain knowledge too. According to empiricists, however, the ideas which we reason about ultimately came to us through the senses. John Locke, for example, refused to accept that children have the ability to understand that = 4, until they learn the meaning of such symbols through experience. Similarly, in order to intuit the validity of the argument All Greeks are mortal, Socrates is Greek, Therefore Socrates is mortal one requires an idea of what it means to be Greek, mortal and Socrates, and according to empiricists these can only be learnt through seeing or hearing about particular instances, or through some other form of sense experience. 2 This is a classical Indian example which I have adapted to the discussion. If you all use it in your exams you will be doing my career, but not yourselves, a favour. Colette Sciberras, PhD (Dunelm)

9 Innate ideas vs Tabula Rasa The empiricist claim that all our concepts and knowledge derive from sense experience suggests that when we are born, our mind is empty and then we begin to acquire concepts and knowledge as we begin to perceive the world around us and learn the names of things. This is known as the tabula rasa view of mind and although it is found in Aristotle, the theory was made prominent by the modern empiricist John Locke. Tabula Rasa translates as blank slate and thus under this account the mind is completely devoid of ideas, until experience starts to fill it. Locke argues for Tabula Rasa 3 by negating the rationalist view of innate ideas. Plato, Descartes and other rationalists hold that we come to the world with some ideas already formed in our minds. A contemporary equivalent view would be that given the structure of the human brain, we are only able to experience and cognize the world in limited ways. Plato thought that a good teacher would be able to draw out knowledge from any pupil, even someone who had never had any previous education. This is famously brought out in the dialogue Meno, where Socrates demonstrates his view of a teacher being like a midwife. Descartes famously believed we are born with an idea of God, and even Hume, an empiricist, thought that concepts such as necessity, causation, substance, and self cannot be derived from experience. This led Hume to suggest that these concepts might not correspond to anything real in the world, that we imagine cause and effect relations. 4 Locke thought that to have an innate idea means that children would be aware of this idea from birth. It was very easy then for him to demolish the theory of innate knowledge, since it is clear that new born babies do not know that = 4. For this reason, Locke is sometimes accused of having attacked a straw man in his rejection of innate ideas. Rationalists who believe in innate ideas, known as nativists, do not interpret them in this way; instead they think that innate ideas are those ideas whose content cannot be gained from experience. A child will not be aware of these ideas until they are triggered by experience and yet experience alone cannot explain how we get these ideas. For example, we understand that a=a necessarily even though we have never seen necessity in this world. Everything in this world is contingent, that is, to a certain extent everything could have been different from the way it is, at least conceivably. Yet, even though we never experienced any instances of it, we have the concept of necessity. In the same way, we never see instances of causation. We understand that, for example, flipping a switch causes the lights to go on or off, but we never experience the actual causing of one thing by another; instead all we see is a correlation between the two events. No matter how far we analyse the process, all we ever see is two different states, we never see one become another. In fact, the only way for scientists to prove causation today is to eliminate, in a laboratory, every other variable 3 In our second reading 4 Without a concept of causation, however, science cannot proceed. How can we explain the relation between gravity and apples falling, say, without saying that gravity causes the apple to fall? This is why Hume, in the end, was sceptic not just of God s existence and of that of the self, but even of the possibility of scientific knowledge. Colette Sciberras, PhD (Dunelm)

10 which is known to co-vary with the effect being studied. That is, we determine cause and effect relations through a process of elimination, and not by any direct observation of instances of causation. Substance, and the related concepts God and self, are further ideas which, if not innate, might be false constructions. Since a substance is defined as that which underlies a thing s changing properties, it therefore has no properties of its own apart from essential ones. Descartes s thinking substance, the I, is known only though its thinking, matter through its extension. But given that thoughts and extension also change, while the thing is supposed to stay the same (see Descartes s wax example) we have still not captured what the substance is. Hume would conclude by this that substances, selves and such might not actually exist. V: Descartes Overview of Meditations Written in the first person, Descartes s Meditations takes us through Descartes s reasoning process in the search for something which is indubitable. The opening Meditation lists the reasons for doubting the senses, and by Meditation II, Descartes has established that, as long as he doubts, he necessarily exists. He perceives clearly and distinctly, the necessary truth of the proposition: I think, therefore I am. One of the main reasons for doubting anything is the possibility that an evil demon might be deceiving us. He might even be misleading us into believing things which we seem to rationally intuit, i.e. the supposed truths we perceive clearly and distinctly, such as 2+2=4. For this reason, Descartes then tries to establish the existence of God as a Perfect Being and not as a deceiving demon. (See Appendix I) Since our clear and distinct innate ideas come from God, we can go on trusting them. From there Descartes establishes the existence of the external world, and of matter as an extended thing. Thus there are two substances in the world, matter and mind. Descartes s dualism went on to influence the course of philosophy and of science, and has been blamed for modern phenomena as diverse as our environmental crises and the split between religion and science. Descartes is often described as a sceptic, and his methodical or hyperbolic doubt, also known as Cartesian Scepticism must be distinguished from Hume s more radical doubt. The method of doubt Descartes builds his entire argument on doubt. His strategy was to hold as false any view that could be doubted, and to go on doing so until he found something that could not be doubted. What could not be doubted was the very fact of his own doubting, and from there, Descartes establishes the necessary fact of his existence, that of God as a perfect being and the existence of the external world. There are many things that can be doubted of course; in fact, as we have seen, the Scientific Revolution and modern epistemology began because of doubts about the veracity of Aristotle s Colette Sciberras, PhD (Dunelm)

11 theories, among others. Descartes outlines three waves of doubt and each wave is bigger and more effective at sweeping away the assumptions we make and the unjustified beliefs that we hold. We believe for example that our senses show us the world accurately, and yet we all know of cases where our senses deceive us. Distance can make objects look smaller than they are; the laws of optics make straight objects appear bent in water. This is the first wave of doubt: that the senses sometimes deceive. It is not a very important fact, because, as Descartes tells us, reason is often able to tell us when we are being deceived. Reason does not always come to the rescue however, most notably when we are dreaming. The second wave of doubt, the dream argument, is different from the first, that the senses deceive, because while we are dreaming we have no way of telling that we are dreaming (unless we have a lucid dream, which is a rather rare experience). If my senses deceive me because I have a fever, reason can tell me that the pink elephants I see are not really in the room. I generally know I am hallucinating. If I am dreaming of an elephant in the room, however, while I am dreaming I am normally deceived into thinking that the elephant is real. It is possible that we are dreaming now, and we do not know it. Or, worse, perhaps it is possible that whoever created me, created me to experience this dream-like reality as real. This third wave of doubt, the possibility of an evil demon who deceives me all the time, is the most powerful in that it sweeps away not only things known through sense perception, but also those known through rational intuition, such as that =4. Perhaps this proposition is false, and an evil but powerful demon put the idea in my mind and made it appear clear and distinct. A contemporary version of this argument can be found in Harman s brain-in-a-vat thought experiment. 5 Anti-scepticism Although Descartes s philosophy is often referred to as Cartesian Scepticism because of the emphasis he places on doubt, his philosophy can also be read as anti-sceptic, depending on one s definition of scepticism. Cartesian Scepticism is also known as Methodic Scepticism or Methodic Doubt, because it uses doubt as a method to reach knowledge and truth. In fact, Descartes s first argument, I think therefore I am uses the fact of his doubting to conclude that he exists. From there he went on to build an entire philosophy that establishes the existence of God, of the mind and of matter as substances. For this reason, Descartes s philosophy is also known as constructivist. There is another trend within philosophy, the deconstructivist trend which seeks to demolish such philosophical edifices as those built by Descartes. Often this approach is inspired by another form of scepticism, known as Radical scepticism. Sceptics of this flavour tend not to affirm or deny any proposition at all and such trends are related to relativism and nihilism to the extent that they deny truth or our ability to know it. These types of sceptics do not form any conclusion other than the view that we can never know anything for sure. 5 Suppose your brain was removed from your body and connected to a virtual reality machine that gave you experiences like walking, etc. Colette Sciberras, PhD (Dunelm)

12 This, clearly, is not the conclusion reached by Descartes. Therefore, when Descartes is described as an anti-sceptic, what this means is that his conclusions went against those of the radical sceptics. Cartesian scepticism is also sometimes referred to as hyperbolic scepticism. This is because Descartes doubt is exaggerated and not always genuine. He doesn t really doubt his senses all the time, for example, it would be impossible for him to have written anything down if he did (for how could he trust that his pen and paper were really in front of him?) In the same way, he doesn t really think he might be deceived by a demon; he is merely supposing that to be the case for the sake of argument, so that he can eventually find one thing which is indubitable. The cogito argument The first thing that Descartes finds to be indubitable, as we have seen, is the fact that he is doubting, or thinking, and from there he goes on to establish that he necessarily exists. As he puts it I must finally conclude that the proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind. In Latin, this is stated as cogito ergo sum, and is generally translated as I think, therefore I am. It is possibly the most famous line of philosophy. Descartes might have said I see, hear and perceive, therefore I am or I dream, therefore I am. But as his third wave of doubt shows, I might be deceived even about the experiences of perceiving and dreaming. I might think that I can see something real whereas in fact I am connected to a virtual reality machine. 6 I might think that I know the difference between dreaming and waking life, and I know that 2 +2 = 4 even in my dreams, but it is possible that a demon is deceiving me about all of this too. Everything I think I know can be doubted, but not the fact that I am doubting. I might be wrong about what I think and perceive, but not the fact that I am thinking and perceiving. Thus for Descartes, thinking includes all those activities that go on in the mind which are, or could be, independent of our sense organs. The most important one is doubting, of course, but Descartes also lists understanding, affirming, denying, willing, refusing, imagining, perceiving. Perceiving is therefore an activity of the mind, although it often requires the senses too. As we see from the brain-in-a-vat, and the dream examples, perception can occur independently from our sense organs. Later on, Descartes will distinguish between sense perception and true perception, or rational intuition. The proposition If I think, then I exist 7 appears to Descartes to be not just true, but necessarily so. Descartes can perceive its truth clearly and distinctly, in other words it is self-evident. To understand the argument fully we will need to consider the notion of substances, but in brief, the argument runs as follows: 1. I can doubt everything, but I cannot doubt that there is doubting and therefore thinking going on. This is because I have direct perception of my mind 6 This is NOT Descartes s example, obviously 7 As you will learn in logic, an argument can be turned into a subjunction. The argument I think. Therefore I am can be rendered into the sentence if I think, then I am. Colette Sciberras, PhD (Dunelm)

13 2. If there is thinking going on, then there must be something that is thinking. Descartes thinks this is self-evident, but Hume, for example, disagreed. We will consider this under substance, below. 3. I am the thing which thinks. Descartes will argue - through his survey of ancient Greek views of the self and soul - that we cannot say anything more about what I am, other than that I am a thinking thing. We will consider this in the next section. 4. Therefore I exist. The 'I' Sum Res Cogitans In Meditations II, Descartes gives a quick survey of traditional philosophical views of the self. He discards the Aristotelian notion of rational animal because of the difficulties of defining rational and animal. Usually we believe ourselves to be made up of a body and a mind (mind or soul mens sive animus), but Descartes thinks these are completely different things. We can doubt whether we have a body, because we only know it through our senses, which sometimes deceive us. We cannot doubt that we have a mind, and this the I, the thing which thinks. Philosophers have sought to define the soul since ancient times, and Descartes refers to the Stoic view of pneuma and to Aristotle s parts of psyche, discounting each as candidates for the I insomuch as they depend upon the body. 8 Descartes will follow Plato in re-emphasising the rational aspect of the soul and rejecting all interpretations of mind or soul that depend upon the existence of a body. This is because the existence of the self can be known a priori, as we have seen, while anything to do with the body can be doubted. Thus for Descartes body and mind are radically different. We will take this up again in the next sections. Descartes defines the body as something which has a shape and occupies a position in space. Still today, the theory of physical continuity as criterion of identity specifies that a person can be known to be the same person over time if his or her body occupies a continuous trajectory across space and time. 8 The Stoic concept of pneuma is related to the breath, the Christian idea of Spirit, and the Indian prana or Chinese chi. It might also be related to the faculty of spirit identified by Plato, which has the virtue of courage. In English, we preserve the meaning in expressions like fighting spirit or to lose spirit. The concept as understood by the Stoics is strongly related to matter in that it is the force that structures matter, a life force or soul. This concept of soul, like Aristotle s, is not limited to something with belongs only to human beings, but is thought to pervade all matter, including non-living things like rocks and water. Aristotle, like Plato, divided the soul into parts, but unlike his teacher and the Stoics, he reserved his understanding of soul, psyche, for all living beings. That is, he disagreed with the Stoics that all matter has soul; rocks and water, for example, have form, but their form is not a soul. The soul is the form of living beings and thus Aristotle disagreed also with Plato s understanding of soul as dominated by intelligence and reason. Where Plato saw a singular function for the soul, which was for reason to control spirit and appetite in a search for the Good, for Aristotle, the soul has multiple functions, key among which are: -Nutrition, growth and reproduction, the activities of the nutritive soul. These are functions of all living beings including plants. -Movement and perception, the activities of the sensitive soul. Only animals perform these functions -Thinking and reasoning, the activities of the rational soul. Colette Sciberras, PhD (Dunelm)

14 Descartes, however, cannot take the body to be the self, because he can doubt the existence of the body but not of the self as a doubting thing. The body, and anything made of matter, can only be known through the senses, which can be doubted, while the I that necessarily exists as a thinking being, is known through reason and the mind. Thus for Descartes the I is that part of me that thinks, doubts, perceives and so on, but not that part that eats, grows, senses the world, moves around in it and reproduces. Our mind is the only thing which we know directly; everything else, we know indirectly. We know about our bodies and matter through the senses, and we know about other minds through inference. Importantly, then, so far Descartes has not established that he has a body, nor that he is alive or a living being. To do that, he will first have to establish that a perfect God who is not a deceiver exists. Secondly, Descartes has not established that anyone else exists. Everyone is capable of proving beyond doubt to oneself that one exists, but no one is capable of proving it to another. This is because I have a direct perception of the contents of my own mind, including doubt, but only of my own mind. This is often referred to as the problem of other minds. Substance One of the most important questions in philosophy concerns existence and what is real and it is understood that there are different levels of being. For example, a piece of wax, when molten, will lose its shape, consistency, colour, scent and seemingly every property it has. Thus there is the idea that these properties, because they can change, are not as real as the thing itself, which somehow stays the same thing. If I asked you what happened to the candle, and you pointed out the molten wax, I would recognize it as somehow the same thing even though all its properties had changed, and it wasn t even a candle anymore. A substance is the thing which underlies all varying properties. Aristotle had recognized two kinds of substances, one of which he thought was ontologically more basic than the other. The most fundamental substances for Aristotle were individuals, such as Socrates, or that candle. The second kind of substance universals - only existed as abstractions from individuals, and yet they were more real than properties. Aristotle therefore disagreed with Plato that forms were ontologically prior to material individuals. Substances are those things, whether material or ideal, of which we can predicate things like is wise (e.g. of Socrates) or smells nice (of the candle). We can predicate things of ideas and universals too; philosophers are wise, the soul has three parts, three is an odd number. Predicates capture properties, which have the least degree of reality. Properties like being wise, being tripartite, or odd, cannot exist without a substance to inhere, without some thing which is wise, has three parts, or is odd. Therefore properties are modes, not substances. If they can change, they are known as accidents. Some properties are essential to a substance and if a thing loses its essential properties, then it is no longer that thing. For example, if it is essential for a candle to have a wick, then once I melt it and remove the wick, it is no longer a candle. Yet somehow, Descartes points out, I recognize it as the same thing. Being a candle, or being molten wax is not essential to what the thing is, and Descartes recognized different categories of Colette Sciberras, PhD (Dunelm)

15 substances than Aristotle. For Descartes, the material thing, the wax, is known only through one essential property, its extension. Importantly, extension here does not mean having any particular size or shape, but the fact of having some kind of size, shape and location in space and time. Thus the one kind of substance recognized by Descartes is matter, res extensa, or the extended thing. The other kind, as we have seen, is res cogitans, mind or the thinking thing. Later on in Meditations, Descartes identifies a third kind of substance; God. God is in fact the supreme substance, the only perfectly real one, since his essence is his very existence. God is the only thing that can exist completely independently from everything else. (See Appendix 1). Matter and mind on the other hand seem to affect one another, and do not seem to be completely independent substances like God. They are conceptually and epistemologically independent in the sense that they can be defined and known independently of each other. In some places Descartes seems to suggest that mind can exist without a body, however he was aware of the problems that his mind-body dualism would give rise to, and tried to give a biological answer. Res cogitans and res extensa The distinction between res cogitans and res extensa is essential to Cartesian dualism and would form the basis for the modern world view. Res cogitans, to reiterate, is that thing which is known through its essential property of thinking, the I. Importantly, the I - my mind and its contents, my thoughts, feelings and other mental phenomena - do not have extension. If we asked, where is your doubt, how big is it? we would not expect to locate it in any particular place, except somewhere in the head, perhaps, 9 and we would certainly not expect to measure a doubt, except perhaps as some kind of electrical impulse on a brain scan. But the brain, and images of brain scans are not thoughts, feelings or perceptions. Mental phenomena seem fundamentally different from physical ones. 10 Anything with extension, anything that can be measured and located in time and space, is a physical object, a res extensa. Inanimate matter does not think, and if other bodies think, we could never know it directly. Matter is only known through the senses, and yet most of the properties through which we recognize matter, like colour or shape, are inessential to it. They change, causing us to be mistaken in our views about things. The one property that is essential to matter is that it needs to have some kind of dimension. Even the smallest particles of matter, subatomic particles and the quarks they are made of, must have some kind of size and be located in space, according to this view Interestingly, some Asians place doubt and thoughts around the heart area. 10 For more on this, see David Chalmers on The Hard Problem 11 Today quarks are known to have the intrinsic properties of mass, electrical charge, spin, and color (i.e. how they interact with other quarks). Mass is clearly related to extension and so would the other properties seem to be, inasmuch as they can be measured. The location in time and space of subatomic particles is a bit more complicated. Colette Sciberras, PhD (Dunelm)

16 In this respect, matter is somewhat opaque to us; we only know it indirectly through sense observation and measurement, and our knowledge of it is open to doubt. This would become known as the veil of perception. Our thoughts, on the other hand, can be known to us directly, even if they cannot be located in space, or shown to others. This essential difference between the two substances of mind and matter would lead to what is known as the mind-body problem. The mind-body problem The problem is that while mind and body seem completely different, as explained above, they also seem to be related to each other. The state of my body definitely affects my mind; if I consume alcohol, a physical substance, there are considerable consequences on my cognitive and emotive performance. Also, if I decide to get up and go for a walk, my decision, a mental phenomenon, has a clear physical effect. How can two radically different things like mind and body affect each other? In short, how can a thing which is essentially physical and opaque to our minds, be moved by a mind, which is essentially immaterial and self-translucent? 12 How can the reverse happen? Descartes was aware of this problem and tried to solve it by claiming that mind-body interaction goes on in the pineal gland. Whether or not he got this right is not very important; what is interesting is that his solution showed what is wrong with this kind of approach. If we define the mind in the way Descartes did, then we cannot point to anything physical as the explanation for mind-body interaction, because we have still not answered the question, how do physical events become mental ones and vice-versa? Even if we narrowed it down and proved that a particular neuron firing produced a thought of Jennifer Aniston 13 the question how? is still pertinent. How does an electric charge passing through a neuron conjure up a thought, or a mental image? No matter how deeply scientists analyse brains, it seems they can never discover thoughts in matter and physical processes. Different answers have been given to this problem, as we shall see. The strong mechanist view is that minds are nothing but matter-in-motion, and consciousness can be fully explained through brain processes. Influenced by the successes of physics, biologists and psychologists have adopted this approach. The behaviourists, for example, discount any mental phenomena, and cognitive scientists and philosophers reduce mind to a program, which they often identify with the material structure of the brain. The process view claims that the problem arises because of the mistaken Cartesian notion of substance; according to this view, it is not things, like bodies and minds, which are fundamental, but processes. Life, mind and consciousness are an emergent properties of physical processes, which cannot be fully explained by the material parts that make up the machinery. Organisation, especially the spontaneous self-organisation that is characteristic of life, plays an important part of this philosophy and seems to restore a sense of their being something special about life, which mechanism seems to negate. 12 My word, influenced by Indian terms. Do not all use Colette Sciberras, PhD (Dunelm)