1 Review Tutorial (A Whirlwind Tour of Metaphysics, Epistemology and Philosophy of Religion) Arguably, the main task of philosophy is to seek the truth. We seek genuine knowledge. This is why epistemology occupies a central position in philosophical inquiry. Since what can be known depends crucially upon what exists, genuine knowledge is determined by metaphysics. What metaphysical knowledge we can have, however, depends crucially upon the ways in which it is possible for us to acquire knowledge. Thus, epistemology and metaphysics are inextricably intertwined. Before we can get anywhere though, we need to be clear on what we mean by knowledge and truth and, indeed, what is real and what sort of existence real things have. Let s focus first on knowledge. You will recall Plato s definition of knowledge as warranted true belief. Defining knowledge as true belief is not acceptable since this would allow purely accidental knowledge. Being warranted to have a true belief solves this problem, but then we need to specify what sort of warrant, or justification, is required. You will recall that there are two possible senses of knowledge. Knowledge in the strict sense requires that we are absolutely certain that a given proposition is true. Because of the limitations of what can be known based on our experience, which was made clear by Descartes, we can have very little of this sort of knowledge. Since we believe that we are justified in claiming that we know things even when we are not 100% certain, such as our claim that we know that the structure of DNA is a double helix for instance, we may want to define knowledge as belief with a high probability of truth, or some suitable modification of this idea (certain knowledge would be the special case where our probability is one). It is important to be clear on what sense of knowledge you are using. Let us now turn to how Descartes establishes how little certain knowledge we can have. Descartes uses a technique called methodological doubt to doubt anything that is not absolutely certain to be true (i.e. doubt all propositions that cannot be assigned probability one). Since the senses are sometimes mistaken, he cannot completely trust sense knowledge, though he supposes that he can trust immediate experience. Later he realizes that he
2 could doubt that God exists, which opens up the possibility of an evil genius systematically deceiving. This causes him to doubt all knowledge based on the senses, including scientific knowledge and his own body, and this enables him to doubt even mathematical knowledge. He thus establishes that there is very little we can know for certain. He argues that the main thing that he can know for certain is that he is a thinking thing. A thing that doubts, understands, conceives, affirms, denies, wills, refuses, which also imagines and feels, etc. A consequence of all of this, however, is that all of our knowledge is not derived from the senses or the imagination but by the understanding only by the mind. What we experience takes place in the mind. Later on in his Meditations, he argues (very roughly) that since we have an idea of God, an infinite omnipotent benevolent being, which cannot come from experience, this idea must come from God. The argument he gives is quite similar to the ontological argument. Recall Anselm s ontological argument for the existence of God, which claims to prove that God exists: the idea of God implies that He is that than which nothing greater can be conceived, and (all else being equal) it is greater to exist than to not, whence God must exist. What kind of argument is this, i.e. what sort of knowledge is it based on? It is an a priori argument. It is not clear that this argument is successful (if for no other reason than because of what Kierkegaard argues). But if this argument the existence of God doesn t work, what else could we try? We must use an a posteriori argument such as Aquinas five ways and the teleological argument (Paley). One of Aquinas arguments (the second way) is the argument (the argument from efficient causes). It proceeds as follows: The first cause in a chain is the cause of all causes up to the present effect. If there is no first efficient cause, there will be no ultimate effect. One cannot follow the chain of causes back infinitely far, since there would be no first cause to cause the ultimate effect. Thus, there must be a first cause, which is understood to be God.
3 You will recall that this argument is fallacious since it equivocates on first ( first changes from meaning earlier to meaning not preceded by another cause ) or it could be considered circular. Then there is also the teleological argument. Paley s version of this argues as follows. If we were to find a watch lying on a beach, its purposeful construction would make us conclude that it had been designed by an intelligent watchmaker. Since the things in the universe appear to be purposefully constructed, and exhibit purposeful behaviour, by analogy, the universe must have been designed by an intelligent universe maker, which must be God. This seems to fall prey to the limitations of analogical arguments, however. Now let s return to Descartes. Why can t Descartes use these (a posteriori) arguments? He needs a successful argument that God exists for him to be able to argue that an external world exists (this is so since if God exists, and He is not a deceiver, Descartes can trust that his senses reflect the existence of an external physical world). This leads Descartes to conclude that there is an extended physical world and a non-extended immaterial mind, which he cannot doubt exists. This leads to substance, or mind-body, dualism the view that there are two distinct fundamental kinds of substance: mind; and matter. There is a major problem with this view, however, since it is necessary to account for how a non-physical mental substance relates to physical substances. And if they interact, it is difficult to understand how a nonphysical substance can have any effect on a physical substance, and vice versa. Thus, we have to contend with the mind-body problem. In any case, Descartes still needs God to exist to get his dualist view off the ground. Kierkegaard, however, gives an argument that we cannot prove the existence of anything. He argues that Reason moves from existence and not toward it. In order to give a proof of the existence of something, we would already have assumed that it exists. So any existence proof is circular. He argues that all we are doing in such a case is developing the content of a conception discovering properties that things have. If this is right, then what do we make of Descartes argument? If it doesn t work, we are just left with our experience, which we cannot get beyond. Thus, it is not possible to prove that dualism is correct. It is natural to
4 believe in an external world, however, since we have from science so much evidence that a physical world exists and that we understand a great deal about how it works (though not how it is in and of itself), and we cannot explain how purely physical stuff can be conscious. But what happens if we reject dualism? This leads to one of three possibilities: materialism or physicalism* (realism about matter); skepticism; or idealism. Let us consider materialism first. Materialists believe that all that exists is physical stuff. Taylor argues that all we really have evidence for is physical stuff and so the belief in a nonphysical mind is pure opinion. We can explain how matter can be living (microbiology). We can explain how matter can reason and calculate (informatics and computer science). We can explain how matter can exhibit purposeful behaviour (cybernetics and self-guiding systems). The only thing materialists cannot explain, however, is consciousness itself. * The essential difference between materialism and physicalism is that materialists hold that all that exists is matter, whereas physicalists hold that all there are are physical things (which includes matter, fields, etc.). On the materialist view, how do we acquire knowledge? It must come from experience and so it must take place much like the way that Locke argues that we acquire knowledge. The basic materials of knowledge are sense data, which are all simple and indivisible. Everything else is constructed by processes such as the repetition, comparison and unification of these ideas. One cannot create simple ideas, they all come from sensation. You will recall the example of the development of general ideas where a baby learns that mother refers to her mother, then mothers in general, which leads to the notion of person, then organism all the way up to the general notion of a thing. (There s an important correction here) Locke was a realist (about matter), he believed in the existence of an external world, but he also appears to believe in the existence of a substantial mind. This would make him a dualist. Recall his discussion of personal identity, where he defined person in terms of continuity of consciousness. He discusses various possibilities of how people can be connected to mental substances (two people in one
5 continuously existing mental substance (mind but associated with a body), one person in two mental substances and many distinct people associated with the same mental substance (reincarnation)). Turning back to the consideration of materialism, what do we make of the notion of truth on this view? The definition of truth germane to a materialist is the definition of truth as correspondence. Since all that is real is physical stuff, propositions are true if they correspond to the actual state of affairs in the world. One may want to consider knowledge, however, to be probabilistic. The reason this sort of definition is desirable is because we can never be completely certain that the physical world is how we think it is or how it appears to be (think back to Descartes). Nevertheless, we still want to claim that we know things about the world (scientific knowledge). The significant limitations of genuine knowledge based on experience, however, might lead one to take a skeptical view. This is the position taken by Hume in his empiricist philosophy. You will recall his argument that all causation is is constant conjunction the regular spatiotemporal contiguity of an experience of a cause and an experience of the effect. Our feeling of a necessary (metaphysical) connection between cause and effect is just our habit of thinking of the effect whenever we think of or experience the cause. This leads to the problem of induction since, due to the fact that we don t experience a necessary connection between cause and effect, we have no reason to expect that the given effect will follow the cause in the future based on the fact that it always has in the past. Due to Hume s skepticism concerning what can be known based on experience, he rejects knowledge of continuously existing physical objects and the knowledge of a continuously existing mind or person. Experience is just a rapid succession of distinct impressions, much like the rapid succession of individual frames in a film. Experience is discrete, so we can have no idea of continuity, whether it be continuity of objects, minds or persons. We are just a bundle of impressions. The illusion of continuity results from the easy transition of ideas permitted by resemblance and causation, which are both related to the comparison of ideas from memory with present experience. The illusion of self-identity arises from the smooth and uninterrupted progression through a sequence of unconnected ideas, a progression facilitated by the relations of resemblance and causation.
6 As a result of this Hume rejects the existence of universals. In thinking of any general concept, our mind simply moves through a series of particulars, we never experience or consider the concept in general. This is contrasted with Plato s view that universals exist. In his case he calls them the Forms. The Forms are the guide of our knowledge of the intelligible world and the cause of the appearance of a Form (an attribute, relation or virtue) in any particular experience. (Remember that there are Forms for particular attributes (colours, sounds, etc.), but also Forms of complex ideas (objects, e.g.), such as the Form of an eight ball). There are also Forms for relations like taller than or between, and virtues such as Justice, and the Good. I just note that, of the notions of truth we have discussed, the notion of truth appropriate for the skeptic is that of coherence. I will discuss this notion of truth later. If one is not inclined toward a thoroughgoing skepticism, then there is another possible position. Taking the conclusions of Descartes process of methodological skepticism seriously, one may reject the physical world entirely, but accept that we have an experience of a variety of different ideas within a non-physical mind. This takes us to idealism. You may recall that Berkeley is taken toward idealism by criticizing Locke s distinction between primary and secondary qualities. Locke argues (roughly) that secondary qualities (colours, sounds, tastes, feelings, etc.) are in the mind since different people can experience different secondary qualities with the same stimulus, but that primary qualities (shape, extension, mass, etc.) are constant and so a properties of physical objects themselves. Berkeley argues that the same kind of perceptual relativity argument can be applied to primary qualities (a table changes shape from different angles, a person and an insect will experience the same object to be of a radically different size, etc.). Therefore, all of the qualities of objects that we experience are in the mind. This takes us back to a position very similar to where Descartes ended up after his skeptical examination of experience. Berkeley takes the further step to conclude that no physical world exists at all. Berkeley also argued that the notion of an extended substance itself is incoherent (where an extended substance is that in which physical (primary) properties are supposed to inhere), which takes him distinctly to idealism.
7 Such an idealist position is well supported based on the fundamental limitations on possible knowledge obtained from experience, but a proponent of this view has the problem of accounting for the great regularity of experience and the great success of scientific inquiry in describing, predicting and explaining natural phenomena. Berkeley accounts for this by appealing to the omniscience and benevolence of God (he did become a Bishop after all). What do we make of the notion of truth on this view? It would seem that the definition of truth germane to idealism is that of truth as coherence (certainly of the two definitions of truth that we have considered). On the coherence definition of truth a particular proposition is true just in case it coheres with the rest of our beliefs. That is, the entire body of our beliefs must cohere, or be consistent with one another, and the consistency of a given belief with the rest of our beliefs is what makes it true. A set of propositions is consistent if it is possible to consider them to simultaneously all be true without any sort of contradiction. As we know, this leads to the odd consequence that a given proposition can be true for one person and false for another. But if there is no physical world for propositions to correspond to and all we have are ideas, what other notion of truth could we have? There is an argument that two people having incompatible sets of beliefs does not undermine a coherence theory. One could argue that in the limit of perfect and complete knowledge everyone would converge on the same complete consistent set of beliefs. On this view, the apparent inconsistency of two people with incompatible yet internally consistent beliefs is just due to imperfect and incomplete knowledge. Russell argued that this is still problematic. We have now seen that the developments in epistemology establish that we can t know for certain (knowledge in Plato s sense) what the world is really like and what is in it. This includes physical substances (matter), mental substances (mind), universals (properties, relations (and virtues)) and God. Ultimately we must choose (either just by making uncritical assumptions or by well considered philosophical reasons, supported by arguments) what we believe exists or can exist. There are a variety of positions on the
8 existence of these things in current philosophical debates. Let us, however, return to the consideration of God. Given that we can t prove that God exists, what should we believe? Recall that Pascal argued that it is more rational to believe that to not believe. He argues that if we choose to believe that God exists (and act accordingly) then we have an infinitely big win if He exists and a finite loss (or gain depending on how you look at it) if He doesn t. If, however, you choose to believe that God doesn t exist (and act accordingly), then you have a finite gain (or loss depending on how you look at it) if He doesn t exist, but an infinite loss if He does. The only way to have a chance a that the infinite gain and avoid the infinite loss is to choose to believe. Thus, the rational choice is to believe in the existence of God. This argument has many problems, however (e.g. it is religion specific). So if we don t accept this, what is the most reasonable thing to believe? Hume points out that based on the fact of evil in the world, it is unreasonable to infer that God exists, since an omnipotent and benevolent God would not allow evil to exist. Based on our experience, it is basically irrational to believe that God exists. Hume doesn t, however, reject the possibility of a theodicy, he just rejects the inference that God exists based on experience (such as, e.g. in the Teleological argument). In response to this sort of argument, Hick attempts to show that a successful theodicy is indeed plausible. In order for people to be responsible for their actions, Hick argues, the must be able to act freely and so must be capable of both good and evil. Thus in order for people to be able to engage in a process of soul making, God must allow evil to exist in the world. Leaving the question of the existence of God aside, where are we now in terms of metaphysics? The standard position on physical substances is that they exist and we have some scientific understanding of what they are like. If the existence of non-physical minds is rejected, this is the very common physicalist position. Whether minds exist, however, is a subject of great amount of debate. Related to this is the problem of how to account for qualia (a class of universals), or the (apparent) existence of phenomenal properties (attributes). Physicalists think they have a way of accounting for this. The fact of consciousness, however, is still very hard for a physicalist to account
9 for, so a dualist position is still natural; physicalists do, however, continue to make proposals for how consciousness may be able to be explained. Aside from this, many people think that a particular class of universal, mathematical objects (or structures), exist independently of space and time. These mathematical Platonists think that they must exist to account for how we explain different scientific phenomena. Those who reject the existence of mathematical entities are nominalists. What about time? The problem with the A-series ordering of times (pastpresent-future) remains, since there is no apparent way to account for what makes the present special. (McTaggart argued that the A-series is essential to time, since time requires change) Since any physical property that could possibly distinguish the present from the past and the future must be possessed by the universe at every time when it is present, this property would be a property of the universe at all times, which implies that there is nothing that distinguishes the present from any other time. There are many A-theorists, however, who provide arguments that an A-series ordering is consistent, none of which are free from problems. The problem of the arrow of time is an extraordinarily complex one. There is an arrow of time wherever there is a time asymmetry. There are a variety of different arrows of time. The ones we considered are: the thermodynamic arrow (increasing entropy); the cosmological arrow (the direction of the universe s expansion); the psychological arrow of time (the increase in memory volume, for example). The most important physical law that has a time asymmetry (or the only one that has an uncontroversial time asymmetry) is the Second Law of Thermodynamics. It is usually defined to say (roughly) that entropy of a system always increases. The entropy can be thought of as a measure of the degree of disorder of a system. Any (spontaneous) physical process, such as a glass breaking on the floor, moves from a state of lesser to greater disorder. You would never see a broken glass leap up off the floor and reconstitute itself spontaneously. The increase in disorder determines an arrow for time. Part of the problem is accounting for this time asymmetry. Since thermodynamics is (usually) not considered to be a truly fundamental theory, it remains to account for it using fundamental theory. This problem is still unresolved. Another is the relationship between the different arrows of time. There are arguments that the psychological arrow can be explained
10 by the thermodynamic arrow. And it is not settled whether or not the direction of the thermodynamic arrow of time would reverse if the universe started to contract. It seems that this is now only a question of theoretical interest, however, since it is now evident that it is not possible for our universe to end in a Big Crunch due to the predominance of dark energy in the universe.