Unity and the Universe

 

 

The universe contains different sorts of unity. There is the kind of unity found in conscious subjects (psychic unity), the kind found in animals and artifacts (telic unity), and the kind found in inanimate objects like pebbles or snowflakes (geometric unity). There is phenomenological unity, functional unity, and symmetrical unity. There are also things that lack unity, such as random collections of rocks in a desert or splashing water: here the parts (if we can call them that) are not organized according to any unifying principle—they just exist as separate entities. We can form sets of them, such as the set consisting of this cup, that fern, and the spider under the table, but there is no natural unity here, no coalescence or collusion. Merely being found next to something else does not a unity make.

            Is the universe itself a unity? I want to say not. The universe consists of a disorganized distribution of bits of matter in space with no internal cohesion or pattern. It is not a psychic unity or a telic unity or a geometric unity. In particular, it lacks symmetry: its geometry is nothing like the geometry of a circle or rectangle. It has no more unity than a sprinkling of rocks in a desert. No doubt such a sprinkling had its causes and was brought about by laws of nature (which might themselves be unities), but what was brought about lacks unity—it is just a mess. Perhaps we can say that planets, stars, and solar systems are unities, but the layout of galaxies forms nothing similarly unified, despite being the result of laws. The distribution of matter across space is chaotic, disorganized, and formless. It is so much spatial noise. It exhibits neither logic nor purpose. It is hard to see how it could be planned or thought out—it just happened that way. It’s all higgledy-piggledy. You would think it had just been thrown there, scattered about, rather than carefully arranged or made obedient to some principle of symmetry.

            We have discovered this to be so. The universe was not always thought of this way: we used to believe that it was a unity. There was the idea of celestial harmony (“harmony of the spheres”), but also the more concrete idea that the universe had the unity of a home—that it had the telic unity of a designed artifact. The earth was our house, the sun our heating system, and the starry sky our backyard. God created this home for us and his own unity was stamped upon it: all the parts were laid out to serve a purpose, with nothing jarring or gratuitous. The universe was not a disorderly mess in which we contingently happened to reside. Even when astronomy went heliocentric, this comforting picture survived: still the universe was conceived as a harmonious unity, a place of purpose and pattern. But twentieth century astrophysics put an end to that picture: not only is the universe unimaginably vast and impersonal; it is also formless and chaotic, a complete shambles. We have discovered that it is not a unity but a plethora: a bunch of stuff scattered about without rhyme or reason. It is not like a home or an animal or even a snowflake. It is a hodgepodge, a jumble, a shapeless agglomeration.

            This discovery has reverberations. First, it puts the idea of a divine designer into serious doubt: for how could an intelligent creator put together such a meaningless assemblage? Wouldn’t we expect at least some pleasing symmetry shaping all this widely distributed matter—a kind of cosmic snowflake? Instead it looks like a child’s rumpus room with stuff scattered all over the place. The impressive extent of the universe seems to confirm God’s majesty (but what is the point of so much space and matter?), but its sheer untidiness doesn’t fit our image of God—what was he thinking?  [1] The galaxies are just dotted about the place without regard for aesthetic or functional form, and their internal structure leaves much to be desired (each one a veritable dog’s dinner). The problem becomes acute if we try to follow Spinoza and identify God with the universe. For Spinoza, God is the infinite and perfect substance, so the universe itself needs to be infinite and perfect. But how could a perfect unitary substance such as God stand in the relation of identity to the formless unorganized universe we have discovered to exist? The universe is not really a substance at all—any more than a random collection of rocks in a desert is a substance. The universe is not a unity, so how can it be God? Surely God can’t be a mess! Haphazardness is really not what we expect from an almighty and discerning God.

Secondly, putting the question of God aside, there is the psychological or spiritual impact of astrophysics. It is often noted that the sheer vastness of the universe, compared to our puny dimensions, is an affront to humanity’s self-important view of itself: we are so small and it is so big! But there is also the disquieting fact that we exist in a vast and chaotic world: space stretches out to astronomical distances (literally) and all that space is populated with disorder and chance. It isn’t even like a city that has grown up over time; at least that has some point and form to it. It’s more like matter has just been chucked there, like so much litter. It mocks our attempts at order and pattern: there is no system, no intelligible arrangement. It’s just one damn galaxy after another. The microcosm has system and unity—atoms and molecules—but the macrocosm is a giant disorganized heap (it would be different if it had the form of a crystal, say). The elements of the universe form no overarching unity beyond that of mere spatial aggregation. The universe has about as much form as your average rubbish dump or junkyard. Come to think of it isn’t that the aspect under which the universe presents itself—as a repository of junk? What are those billions of galaxies but so much astronomical garbage, taking up space but serving no purpose?  [2] Biologists speak of junk DNA; well, aren’t vast swaths of the universe so much astronomical junk? You could make a bonfire of it all and lose nothing of value. The universe is a pile of pointless old garbage (even if there are some nice glittering jewels amidst all the dull lumps). Who needs the asteroid belt, for example? It isn’t as if we have found the universe to be some sort of mathematically marvelous super-entity with all sorts of lovely symmetries and a cosmic purpose to boot; no, we have found it to be a disorderly dumping ground for chunks of old matter nobody wants. Unity is the last thing it has on its mind.

You may think I am being too hard on the universe, not giving it its due. You may think I am overstating the universe’s disarray, its charmless lack of structure (as if it is ungrammatical), but consider what we know of its origins. It came about from an explosion (the big bang): there was a previous universe, an antecedent reality, which literally exploded to form the current universe.  [3] This universe, our universe, consists of debris from that explosion, flying out with great velocity into space. And what does debris from an explosion look like? It looks like an unholy mess—anything but orderly. Explosions don’t leave pleasing unities; they leave chaos and disorder. Our universe is the result of an explosion and it has just the properties you would predict from that fact. Our universe is a bombsite, a blast scene, a debris field. It is the result of a shattering and splintering (“the splintered universe”). We can reasonably suppose that the previous universe had some sort of inner unity–enough to constitute a bomb at least, and maybe more (it was not itself the result of an explosion). Then the big bang was the undoing of this unity. The previous universe killed itself in the big bang, destroying its unity and replacing it with the chaotic remains that we see today. If we think of it as analogous to a pane of glass, then the big bang was the shattering of this pane’s unity into a million shards: from organized unity to shapeless heap—or better, an expanding front of fragments whipping through space.  [4] Explosions convert unities into non-unities—surviving fragments, formless debris. Thus we live amidst the ruins of a previous world. Compare the demolition of a building: from a cohesive structured form it instantly turns to dust and jagged fragments. That is our universe: the result of a previous universe demolishing itself. Some unitary parts may survive demolition, but the whole entity does not. Our universe contains some unities, possibly prefigured in the previous universe, but not the original cosmic unity; all that is left is a random distribution of dispersed elements. We live in a razed and ruined city. The universe we know consists of the ruins left behind when the previous universe violently put an end to itself. We could call the big bang the “big splintering”. We are accustomed to thinking of it as an act of creation, but it is also an act of destruction. All explosions create something—their remains—but they are mainly destructive. From the point of view of the previous universe, the big bang was anti-creative: it destroyed what went before. True, it created the bombsite in which we now uneasily reside, and that bombsite has taken on a life of its own (as architectural ruins often do). But the process was a destructive explosion, leaving only debris (initially the big bang produced nothing but formless gas). Given the nature of the universe’s origin, then, we should expect chaos and disorder—the usual results of an explosion. Bits of matter are distributed according to the initial explosive event and whatever forces the bits themselves exert. The expanding universe is simply the universe as it acts after an explosion has propelled it into space.

We know little if anything about the nature of the previous universe, but it seems reasonable to suppose that it was unified—a unity. What kind of unity? In principle it could be anything from our three categories—psychic, telic, or geometric. Or maybe it had some other type of unity whose name we don’t know. The question seems worth investigating: is it possible to infer anything about the nature of this unity from the results of shattering it? What we do know is that the universe that succeeded it is not a unity; and we know why—it’s a debris field. It isn’t the result of a de novo act of constructive creation; it’s the result of a pulverizing act of destruction—the dismemberment of a prior cosmic unity. The big bang destroyed in order to create; or better, it destroyed and accidentally “created” (we don’t create ruins). What we call Creation could equally be called Destruction. You can create a desert by destroying a city, but that is not a terribly impressive form of creation. The previous universe might have been a beautiful unity, only to be replaced by a broken landscape of charred remains. Our universe is like the smoking remnants of a once great metropolis. We have eked out a place in it, like rats in a bombed-out building, but we can’t deny that it is a palace brought to ashes.  [5] We literally live in an exploded (and still exploding) world.

It can take a while before scientific discoveries sink into the human imagination. The heliocentric view is still sinking in, and Darwinian evolution has yet to penetrate deeply and widely; the big bang and associated cosmology have not made much of a dent in old preconceptions. That is, our imagination is stuck in an earlier epoch; we need imaginative forms of expression to make the reality of the universe vivid to ourselves (even if we grasp it abstractly). It is not enough to know it; we have to feel it—feel its consequences and ramifications. Science needs poetry. Here I have tried to articulate what modern cosmology is telling us by emphasizing the lack of order in the layout of the universe and the meaning of the big bang as an act of destructive creation. The universe is less a magnificent cathedral than a pile of remnants. At the moment of the big bang the previous universe was literally vaporized, existing as nothing but free-floating gas, formless and devoid of unity, the very picture of destruction, as if the previous reality had gone up in smoke. But even when gravity began to form pockets of solid matter the universe was still in the throes of the initial destructive act, and the onset of life did not change that. Life on earth evolved on a piece of debris flying through space after the initial cataclysm. We humans live among the remnants of a universe-busting event, a place of disarray and disorder. It is nothing like the friendly and harmonious world depicted by world religions and the mathematical speculations of the ancient Greeks.

 

  [1] Everyone knows the story of Russell extolling (but also lamenting) the vastness of space and Ramsey replying that he wasn’t much impressed with bigness, since he was quite big himself; the human mind was what impressed him. I wonder what both men would say about the unending messiness of the universe.

  [2] You might reply that they could be home to advanced civilizations or at least contented animals, so they are not junk to them. But they might not, and even the ones that are will be mostly redundant junk. Face it: the universe looks like the work of a particularly determined and indiscriminate hoarder.

  [3] I will speak of a “previous universe” though I could make the same points by speaking of previous states of theuniverse. This seems a more apt way of speaking to me, given that the pre-big bang universe must have been radically different from what we see today.

  [4] I should note that on the standard interpretation of big bang cosmology space did not pre-exist the big bang but came with it: space was created by the big bang and expanded as matter was accelerated by it. However, this does not detract from the truth that the big bang was a type of explosion: an abrupt radiating force stemming from a spot of exceptionally high density, pressure, and temperature.

  [5] Of course, I don’t know that the universe before the big bang was a “palace”, but grant me some poetic license. It must have been something other than scattered debris from a prior explosion, since debris doesn’t explode. Astrophysicists speak of a “singularity” and that captures the idea of unity I am working with: the pre-big bang universe was not a sundered mishmash but a concentrated oneness.

                                               

 

 

 

 

 

What is Remembering?

 

 

 

Not much philosophical attention has been paid to the concept of remembering, in contrast to perceiving and communicating (as well as thinking, reasoning, knowing, believing, imagining, willing, intending, acting, feeling, consciousness, and other concepts). How should remembering be conceived? Nabokov entitled his autobiography Speak, Memory: this provides a suggestive starting-point for inquiry into remembering. It suggests that memory works by communicating with the conscious subject—sending messages for conscious recall. Memory speaks to us: that is what remembering is—receiving information transmitted from stored memories. Remembering is hearing messages about the past; it is listening to the past (or information about it). Call this the “communicative model”: the idea is that just as we receive messages from other minds in acts of interpersonal communication, so we receive messages from the part of our own mind known as memory. Remembering is a receptive act, rather like hearing someone speak; but it results from a productive act, like acts of speech themselves. Remembering is listening to a voice within. We should interpret “hearing” and “listening” broadly here, since the deaf can remember but don’t have the power of hearing audible speech. Remembering is a symbolic communicative act, but not necessarily one based on the sense of hearing.

            Perhaps the best way to motivate this theory is to link memory to thought. If we are already predisposed to accept a language of thought, it is no giant leap to extend this conception to memory. Memory clearly interfaces with thought, and if thought is symbolic, then so is memory. Thoughts mingle with memories as they well up from the unconscious, so it is likely that they share a symbolic medium. The mingling is like a conversation between two voices—the voice of memory and the voice of thought. There is a LOT and a LOM and they inter-translate. This theory stands opposed to the theory that remembering is perceiving what lies in memory—that conscious recollection is sensing or apprehending memory traces. Call this the “perceptual model”: memory doesn’t actively communicate its contents; its contents are passively perceived by the remembering subject.  [1] According to the perceptual model, Nabokov should have entitled his memoir Let Me Have a Look, Memory: we scan our memories, as we scan a perceptual scene; they don’t speak to us. Remembering can be modeled either on interpersonal communication or on sense perception. Does memory talk to us or do we gaze at it? Is it an agent or an object?

How can we decide between these two theories? One way is to consider the role of the will in remembering. We can try to remember but we can also try to forget, and we can fail at both. Memory might choose not to speak or it might choose to speak too much: it can either refuse to yield up the information we seek or it can give us information we don’t want. We have limited powers when it comes to accessing our memory, as if we are contending with another agent, possibly with its own agenda. It is hard to square this with the perceptual model: just as we can open or shut our eyes and see or not see, so we should be able to access or block perception of memory at will. Objects of perception don’t actively thwart our will, unless they too have will; but memory appears to have a mind of its own, at least some of the time. It can be cooperative or uncooperative. Consider how memory intrudes into dreams, selecting and trimming, acting like an autonomous agent: it isn’t that dreams are perceptions of memories, driven by the conscious wishes of the dreamer. There is something like a gatekeeper that controls what memories get into the dream and what don’t. It is not so different in waking life: a traumatic memory may insist on making an appearance no matter how much its possessor may try to suppress and banish it. Yet a pleasant or useful memory may remain hidden and inaccessible no matter how hard you try to bring it to awareness. When Nabokov writes, “Speak, memory” he is asking or requesting his memory to speak to him, knowing full well that it may be reluctant to do so; he could equally write, “Don’t speak, memory” if his memory is plaguing him with the past. This is not how we think of a perceptual object—as if it needed to be coaxed into cooperating. We know that memory is active and self-organizing, reconfiguring itself over time, sometimes dramatically so; it is also agent-like in its discretionary powers, sometimes declining to yield up its secrets, sometimes gushing too much. It can be frustrating and infuriating, like a wayward speaker who insists on saying either too little or too much. Nor is its accessibility merely random—there is a method to its disclosures, though it can be hard to divine what that is. This is where we venture into Freudian territory, but there is no need to buy into the whole Freudian apparatus to recognize that what we remember or forget is related to our emotions. Memory is a kind of intentional system, much like a communicating agent; it is not like a passive object of perception, waiting indifferently to be scanned or searched. It speaks or it remains silent, while a perceptual object sits there neutrally.

            It is anyway strange to think of remembering as like seeing a memory—as a brain scientist might see a memory trace in the brain. Surely we don’t literally sense our memories, scrutinize them, view them from different angles. Nor do we introspect them. We are more the recipients of their publications: they speak and we listen, or they remain silent and we hear nothing. The memory system is an active component of the mind, interacting with other components (thought, language, emotion): what is remembered is what is actively delivered to the conscious mind. Memory issues bulletins or keeps its cards close to its chest, according to inscrutable principles (dreams being the clearest example of this inscrutability). It isn’t that it sits there passively awaiting our inspection, playing no role in determining what is remembered. It may even see fit to transmit false memories that deceive the conscious mind—like a speaker who tells lies. Memory can fabricate and confabulate, like the most imaginative and untruthful of speakers, sending us wildly misleading messages. It seems to be doing so on purpose. It isn’t just a storehouse of inert items through which we rummage. It actively asserts that p, truly or falsely, aiming to secure our assent, purporting to be a source of knowledge.  [2] It is more like an orator trying to persuade than a tree standing stiffly before our eyes. One might even come to view one’s memory as a congenital liar, constantly purveying falsity, propaganda, and prejudice. Memory is notoriously susceptible to the promptings of emotion—the original unreliable narrator. It makes things up as it goes along. It can do this only because it operates like a speaker.

            Memory has two jobs: it stores information unconsciously and it transmits information to consciousness. There is not much point in doing the first job if the second is not performed. This duality is analogous to the standard communicator: she contains a store of information (knowledge) as well as the ability to transmit that information to another person. She may be reluctant to transmit the information or she may be enthusiastic about it, as in the case of memory; she may also be good or bad at information transmission, as people have good or bad powers of recall. The structure is the same in both cases. What differentiates them is that we have a full-blown agent in one case but not in the other—an actual person doing the transmitting. In the case of memory we can say that we have a quasi-agent, since memory acts like an intentional system, but it is stretching the point to suggest that memory is a person. Can we find a way to make the analogy complete? Here goes: memory involves a past selfthat speaks to you. At a certain time of your life you had certain experiences and these were laid down in memory, more or less permanently; you later recall them, as your memory communicates its contents. The memories refer back to an earlier time in the life of a person, possibly long ago. Consider a memory that stems from childhood, well before your mature self has formed: isn’t it just as if your childhood self were speaking to you across the years? Doesn’t the memory embed that earlier self in all its innocence and naivety? The memory is saying to you, “I had this experience”. Or rather, your previous self is saying that—sending you a message in a bottle from the past. It is you speaking, or a self that preceded your present self. The memory is a speech act from a previous person. The speech act is delivered by an actual agent—a previous self no less. Such memories have a peculiar charm and magic to them, precisely because they hail from a remote self. In that memory you can hear your old self remotely speaking to you. That self speaks to you through memory. Persons and memories are bound together, so a memory message is connected to a particular past person.

            When I say that memory operates like speech I don’t mean to restrict the means of communication to the standard devices of natural language. The language of memory could take many different forms: it needn’t consist of a pairing of sound and meaning (or a pairing of gesture and meaning in the case of sign language). It could employ sensory materials in the messages it sends—mental images of the past: visual, auditory, tactile, olfactory, and gustatory. No doubt many of our memories are clothed in such sensory materials. But that does not invalidate the communicative model or favor the perceptual model (these are not sensory images of memories, but of past events  [3]); it merely tells us that the medium of communication is sensory. Memory employs sensory elements to form the messages it transmits to consciousness—hence their characteristic phenomenology. Its speech acts incorporate pictorial constituents (if that is the right way to view mental images). It need not all be bloodless syntax in an arcane computational language, or insistent voices in the head. Memory can send us messages about the past in the form of visual pictures. The important point is that the means of transmission is like communication (not like perception): it is kind of telling, a letting know, a sharing of information. It is not like the imprinting of an object on a sense organ. Memories speak to us; they don’t present themselves for perceptual inspection. Remembering is like hearing someone talk. It is not like perceiving traces of the past inscribed on a mental parchment.  [4]

 

Colin McGinn   

  [1] This is sometimes called the “searchlight” theory—remembering by directing a light on the contents of memory. By contrast, the communicative model compares remembering to utterance: memories as reports of the past. 

  [2] Thus knowledge of the past emerges as a kind of testimony-based knowledge: we know about the past because we have heard testimony about it—because memory has spoken to us. We don’t know about it by (currently) perceiving it.

  [3] I am not ruling out a perceptual model of our psychological relationship to past events, just our relationship tomemories of such events. I don’t favor that model of memories of events, but it is compatible with the communicative model of remembering itself: we see past events by being told about them. Memory speaks to us and we thereby become perceptually acquainted with the past. This would be the analogue of perceiving a present object by being told about it—perception by means of testimony. This is a strange idea, no doubt, but not incompatible with viewing memory as speech.

  [4] The classic idea of a memory trace invites the perceptual model—we detect these traces by a process of internal scanning. The trace is like a visible footprint left by the past. But this model is not obligatory and it fails to capture the active and selective nature of memory. No doubt there are states of the brain that correspond to memories, but it is a further step to identify the two. And the existence of such brain states is quite compatible with the idea that remembering is essentially a communicative process (there are obviously correlated brain states in individuals that communicate). The important point is that remembering is a kind of listening: thus the aptness of Nabokov’s title. In remembering your mind speaks to you of the past.  

                                               

 

 

Agnosticism and Skepticism

 

 

Consider a tribe of natural-born agnostics concerning the existence of the external world. This tribe regards it as plain common sense that they do not know whether there are any external objects. They have no inclination to believe in external objects, but neither do they disbelieve in them—they are comfortably neutral on the question. (We may also suppose them to be agnostic on other matters too: other minds, the future, the past, whether there are any gods). They agree that it is possible that external objects exist, but they have no positive tendency to believe in them. At the same time they are not agnostic about the existence of their own minds: they are firmly convinced that they have minds and they take themselves to know many truths about their minds. They are not dogmatic agnostics! We can suppose that the tribe takes up a whole planet populated by (say) 6 billion people; there are no other tribes on the planet that accept the existence of an external world. Agnosticism is simply taken for granted, not disputed, universally shared. If you ask them about their state of knowledge, they will tell you that they are certain that agnosticism is the right position; nothing else is rational. They will point out that they are not agnostic about their own mental states, because these are directly given to them, and then note that no such direct knowledge is possible for the material world (if there is such a thing). Confronted with our habitual beliefs about the external world, they would declare us credulous epistemic dupes. These folks are cautious to the marrow.

            What do the philosophers of this tribe do with their time? They are certainly not skeptics like our skeptics: there are no positive beliefs held by their compatriots about the external world that they can deem unwarranted. They are not skeptical about widely held beliefs of this type, since there are no such beliefs to be skeptical about. No one believes in an external world, so there is no need to urge epistemic caution with respect to such beliefs. There is no point in philosophy classes that set out to disabuse the young of the dogma of the external world, because no one accepts that dogma—it would be like taking coals to Newcastle. So are the epistemologists out of business on the agnostic planet? Is there nothing they can disagree with? Is there no demand for their services? Like philosophers everywhere, they take it as their duty to question widely held beliefs, but the beliefs that exist on their planet are not like the beliefs that exist on our planet. Still, some beliefs exist there—so there is something to question. What might they fasten on?

I envisage two lines of questioning that might occur to them: first, questioning people’s confidence in their judgments about their own minds; second, questioning people’s confidence that agnosticism about the external world is the only reasonable position. There might be professional epistemologists on this planet whose reputations are built around these two lines of questioning. The universal agnostics will wonder why people subscribe to such a sharp contrast between the mind and the external world, pointing to cases in which (they claim) people make mistakes about their own minds. Thus we have skeptics with respect to knowledge of the internal world—they are skeptical of the generally held belief that knowledge is possible here. Then we have those philosophers skeptical of agnosticism about the external world: they question the belief that the external world cannot be known. In the culture of the tribe this kind of philosopher is deemed the more radical: for in that culture agnosticism about the external world is so deeply entrenched that any attempt to question it is immediately suspect. At least the first kind of philosopher doesn’t attack the very roots of their belief system; she merely suggests extending their general agnosticism all the way down. That seems to them epistemologically commendable: it is good not to overreach in matters of knowledge attribution, and it is salutary to be reminded that even in the securest of domains there is always room for doubt. These skeptics have their heart in the right place, merely preaching a general caution that is taken as gospel elsewhere. Their motto is: It’s always better to be cautious than wrong.

            But those who suggest that agnosticism about the external world is a false doctrine are another kettle of fish: for they are claiming to have knowledge that it is manifestly impossible to have. Everyone agrees (save the odd madman) that no one can know that external objects exist–no matter how much it may seem that they do (and things don’t really seem that way to deep-dyed agnostics); and yet these so-called “philosophers” keep insisting that they can and do know that. This strikes ordinary hardworking people as a laughable conceit, wildly counterintuitive on its face, and vaguely unethical to boot. It therefore provides good material for radical professors giving university classes to susceptible young minds. Government officials regularly complain that professors are trying to convince the young that they can know that they have a body. Outrageous! Any fool can see that such knowledge is impossible; to suggest otherwise is to undermine the very fabric of civilization—built as it is on the incontrovertible principle that it is wrong to believe that which cannot be proven. To claim knowledge of an external world is to fly in the face of centuries of hallowed tradition, as well as conflicting with the innate Light of Reason. But those wayward philosophers stubbornly maintain that they have arguments for their subversive views, paradoxical as their arguments may sound. Some claim that external objects are really constructions from sense data, and we can know of their existence. Others hold that inference to the best explanation justifies belief in an external world. Yet others maintain that they know intuitively that external objects exist, or that God has disclosed this fact to a select few. Interestingly, no one is ever persuaded by these arguments, except in a feebly academic sense. They may accept the existence of an external world while closeted in the study, but when they return to ordinary life they slip back into their habitual agnosticism (and in truth the philosophical arguments are just not very good). It is just so much more natural to believe that human knowledge is limited, and that nothing can be inferred from the existence of an inner world about the existence of an outer world. The philosophical arguments may be ingenious and fun to think about, but they do nothing to dislodge the deep-seated agnosticism of our tribe. Their natural caution is not so easily shattered.

            The lesson is that philosophical skepticism exists against a cultural (or biological) background of generally held assumptions—it is skepticism with respect to a particular body of entrenched beliefs. In our case the body of beliefs entails that there is an external world and that it has a certain character—we take ourselves to know things about this world. The skeptic questions our general confidence in these beliefs. In the case of the agnostic tribe the body of beliefs entails that nothing can be known about an external world—and that this fact can itself be known. The skeptic then questions this assumption, holding that the external world can be known to exist. This is equally a form of skepticism, since it questions a widely held belief—it is skeptical with respect to that belief. There is no such thing as skepticism tout court—as if the only conceivable kind of skepticism questions the belief that certain things can be known. Some skepticism questions the belief that certain things can’t be known. It all depends on the culture in which the skeptic operates. If a culture believes that the existence of the gods can be known, but not the existence of the self, then skepticism will take a very different form in that culture. The skeptic here would claim that the existence of the gods cannot be known, but the existence of the self can be. Someone who denies that the existence of external objects can be known is not ipso facto a skeptic—since no one may contest that claim. The skeptical philosophers on the agnostic planet defend knowledge of the existence of the external world, but they are nevertheless skeptics—relative to that culture. The naturally agnostic people are not skeptics, because they challenge no generally accepted beliefs. It never even occurs to them to believe in external objects, so their agnosticism is not a rejection of anything believed. Agnosticism is not in itself a form of skepticism—it merely asserts that certain things can’t be known.  [1] To be a skeptic you have to challenge something that is generally believed, but what is believed can vary from case to case. Skepticism is culturally relative: to be skeptical is to be skeptical with respect to the beliefs of a culture. Skepticism is essentially an attack on entrenched beliefs, not a set of beliefs in its own right. This is why epistemic caution can be an object of skepticism, as well as epistemic recklessness.

 

  [1] If you say that we can’t know about galaxies beyond the reach of light or exactly how many dinosaurs there were, you are not a skeptic—since no one disagrees with you. A skeptic needs an opponent, preferably a large group of them.

 

 

 

One Substance

 

 

Spinoza’s view that there is just one substance is immensely attractive, but can we give any argument for it? How do we rule out many-substance views? We are accustomed to considering dual substance views such as Descartes’ dualism of mind and matter, but these don’t exhaust the field. We can formulate a fourfold substance metaphysics: Kantian things-in-themselves which are not spatial, perceptible matter which is spatial, finite minds such as our own, and the infinite mind of God. Arguments can be given to show that these are four fundamentally different kinds of substance; and of course we could reduce the number to three by omitting God or noumena. In principle there is no limit to the number of distinct substances there could be (we could add abstract substance if we so desired); we are not restricted to monism and dualism. We could stipulate a world in which there is a plurality of (types of) substance even if ours is not such a world. The question is what could count against the idea of a world of many substances.

            What would count in favor of it is causal isolation. If two substances could not causally interact, that would indicate that they have fundamentally different natures, so different that any causal commerce between them is ruled out. This is the case for the abstract and the concrete: here causal interaction seems out of the question (the abstract entities aren’t even in space and don’t change). If our minds cannot interact with the mind of God in such a way as to change it, then that is a reason to suppose that the substance of God is not like our substance. Similarly, if mind and body cannot interact that would suggest that these are distinct substances: they don’t interact because they are not of such a nature that they could interact. Causal isolation is evidence of a diversity of fundamental nature. All physical things can in principle interact with each other, so they belong to a single category of substance; but if some could not, that would be a reason to suspect diversity of substance. If we came across a world that exhibited marked causal isolation between mind and body, or between our minds and God’s mind, that would indicate that we are in the presence of distinct substances.

            The standard objection to Descartes’ dualism is that such different substances could not possibly interact. How could a substance whose essence is extension cause changes in a substance lacking extension? And how could extensionless thoughts bring about changes in extended bodies?  [1] Yet mind and body do interact, so there can’t be a duality of substances. This suggests a criterion of identity for substances: substances are the same if and only if they can causally interact. If they can’t interact they are not the same, and if they can they are. Now the question is how causality actually operates in our world—does it connect everything with everything? It doesn’t connect the abstract to the concrete, so here we have deep ontological diversity; but it does connect mind and body (and it might connect noumena and phenomena or finite and infinite spirits). So we can argue as follows: since mind and body causally interact they must be of such a nature that they can so interact, but that requires a commonality of nature at a deep level. It can’t be that the whole nature of matter is extension (or gravity or electricity) while the whole nature of mind is lack of extension (or lack of gravity or electricity); there has to be some common ground at some level.  [2] Thus these attributes must be aspects of an underlying substance that unifies what we call mind and matter—essentially Spinoza’s position. If we reject causal interaction between mind and body, we can insist on a duality of substance (as with Leibniz’s pre-established harmony); but if we allow it, then we face the question of what makes it possible. If causation runs right through the world in a single giant web of causal connection, then the world must be fundamentally unified, i.e. there is just one substance. And it does appear so to run.

            This doesn’t mean that we can conceive the world as unified, except in a very abstract sense; our concepts and perceptual perspective may block us from appreciating its unified nature. But we can appreciate that causation runs through everything with no causal blocks (not counting the abstract), so we have a basis for supposing substance monism. If a subjective percept is caused by an objective stimulus, then cause and effect must share an underlying nature—the two must belong to the same “world” (similarly for noumena and phenomena, or our minds and God’s mind). Hume called causation the cement of the universe; well, it is a universal cement—a thread that sews everything together (to change the metaphor).  Things cannot differ that much if they are in regular causal connection with each other—if interaction is natural to them. For causation must work intelligibly not magically (that’s why we balk at action at a distance): causes cannot bring about effects in things that share no properties with them. If A and B are radically different kinds of thing, they cannot causally communicate—which is why Descartes’ dualism has so much trouble with causal interaction. He has defined matter and mind in such a way that they cannot interact, since their entire essences are antithetical to each other. It would be different if, in addition to extension and thought, he had credited matter and mind with further properties that bring them together; then he could maintain that the interaction works by means of these further properties, whether known or unknown. The problem is that he has defined the two in such a way that their whole nature is distinct. Where Spinoza sees two modes of a single underlying world substance, Descartes sees an irreducible duality of substances: but then he has no account of causal interaction. He is trying to have it both ways. But granted causal interaction, a unity of substance is the indicated conclusion. Causation dissolves ontological distinction. A causally connected world is an ontologically unified world.

 

  [1] Note that there is not supposed to be a problem about causation within each domain; in particular, it is not supposed that the immaterial mind is incapable of causal relations involving itself alone (thoughts causing other thoughts). The problem concerns causal relations across substance boundaries, in which cause and effect are of vastly different types.

  [2] The cause must have an active power capable of bringing about the effect it does, and the effect must have a passive power which makes it capable of being brought about by that type of cause; both powers must have a basis in the categorical properties of cause and effect. We can’t just jam any two kinds of thing together and call them cause and effect: they have to suit each other in order to be joined as cause and effect.