Spinoza's Panpsychism Martin Lin Rutgers University Spinoza is a panpsychist. For him, mentality is a pervasive and fundamental feature of the natural world. But he also believes the much stronger claim that every single physical thing-plants, rocks, stars, donkeys, the organs of a human body, etc.-has a mind. This is because he identifies each of God's ideas with a mind. Because God is omniscient and has an idea of each physical thing whatsoever, each physical thing has a mind. Why does he believe this and what does it mean? Before we try to answer this question, it will be useful to review some basic features of Spinoza's metaphysics. To begin with, Spinoza thinks that there is only one fundamental being or substance, which he identifies with God or Nature. That is, Spinoza naturalizes God or, alternatively, deifies nature. (Henceforth I will use 'Nature' with a capital 'N' to indicate this substance.) Nature is something that is "in itself." By this, Spinoza means that there is nothing more fundamental than Nature in terms of which the existence of Nature can be understood. Nothing explains the existence of Nature, either causally or metaphysically, but the nature of Nature itself. For this reason, Spinoza says that Nature is self-caused. Nature is also conceived through itself. That is, thinking about Nature does not require thinking about any other thing. Nature is conceptually self-contained. Spinoza thinks that these features entail that there can be only one Nature and it is infinite, eternal and necessary. Nature, the one infinite substance, can be thought of in infinitely many ways. These ways of thinking about Nature are called "attributes" and they express its essence. These attributes are different ways of thinking about or conceiving of the essence of Nature. For reasons that are obscure, Spinoza thinks that we know only two of these attributes, thought and extension. 'Extension' is Spinoza's word for the physical. Leaving aside the unknown attributes, we can think about Nature as both mental (thinking) and physical (extended). Nature can be conceived under either attribute. The important point for our purposes is that Nature thinks. It has ideas, which constitute its thoughts. Nature is also physical. Bodies of all sorts (particles, human bodies, stars, etc.) are modes of Nature conceived physically. What does nature think about? It thinks about itself conceived of physically. That is, its ideas represent its modes of extension including bodies. It is important to emphasize that Nature conceived of as thinking is the very same thing as Nature conceived of as extended. Thought and extension are not two essential properties of this nature. Rather, they are different ways of thinking about the very same essence of the substance. Thus, Spinoza is a conceptual dualist but not a metaphysical one. How can Nature be thought of in two different ways without those ways implying a metaphysical difference? The answer is that these different ways of conceiving do not say different things about Nature. Their contents are identical. They merely express those contents in a different format or present them differently. Because both thought and extension are equally fundamental, Spinoza is neither a materialist nor an idealist. Nature can be completely and accurately represented as either mental or physical. 2 Spinoza thinks that there is only one fundamental thing but that there are many derivative things. His terms for these non-fundamental beings are modes. Cabbages, kings, shoes and ships are all modes of nature. So too are the human body and mind. The correct metaphysical analysis of these modes is a controversial matter. Many readers of Spinoza think that they are properties of Nature. In this paper, I will proceed on the basis of an interpretation according to which modes are Nature insofar as it satisfies certain conditions. This should be understood on the model of a wave, which is a medium insofar as it oscillates, or a fist, which is a hand insofar as it is clenched. Bodies are thus like waves on the oceans of extension and minds are like waves on the oceans of thought. Modes so conceived are not properties. We can see this by considering the following example. The ocean insofar as it oscillates (a subject insofar as it satisfies some condition) is noisy. But the expression the ocean insofar as it oscillates does not refer to a property. We can see by considering the falsity of the statement the property of oscillation is noisy. Not only is this statement false but any statement that attributes the property of being noisy to a property is also false. And thus, generalizing from this case, we can conclude that any expression of the form x insofar as φ doesn't refer to a property but rather an object. Minds and bodies are modes and so, on this construal of modes they are objects. Such objects as waves, fists, and dents are obviously derivative objects. We can say that they are constituted by the subjects that, in virtue of satisfying some condition, determine them to exist. Although I will proceed on the basis of this interpretation, none of my conclusions depend upon it. Those who prefer alternative interpretations are free to substitute them in what follows. Mind in the Seventeenth Century Spinoza's philosophy of mind is in many respects a response to a revolution introduced by Descartes. According to Descartes, the mind and body are two distinct substances that have nothing in common. Among the characteristic features of the mind are consciousness, simplicity, and being the cause of intelligent action. Mind is also the substance in which perceptions and volitions inhere. The nature of body is three-dimension Euclidean extension. Individual bodies are regions of three-dimensional extension that are capable of motion and rest. Because we can clearly and distinctly conceive of minds existing independently of bodies, Descartes concludes that the mind and body are distinct substances. On this picture, the physical world is cleanly separated from the mental world insofar as they play no role in metaphysically constituting one another. Causal connections do, however, run between the mental and the physical. Inputs from the physical world causally explain sense perceptions in the mind. Outputs from the mental world causally explain the bodily motions that constitute intelligent action. Thus Descartes endorses mind-body substance dualism with causal interaction. Many seventeenth century philosophers who are otherwise sympathetic to Descartes' innovations in the philosophy of mind reject mind-body interaction. How can two substances 3 with nothing in common causally interact? For many post-Cartesian philosophers, the answer is that they can't. Fire heats because it is hot. Donkeys beget donkeys because they are donkeys. Similarity is required for causation.1 Spinoza is among those philosophers who are sympathetic to the Cartesian notion that mind and body are dissimilar but is hostile to interaction. Spinoza is hostile to the idea of interaction because there are no connections between the concepts of two things that have nothing in common. There must be, however, connections between the concept of an effect and the concept of its cause. Therefore, two things with nothing in common cannot causally interact. It is not an easy thing to deny mind-body interaction because there are many correlations between the mental and the physical that strongly suggest interaction. When I want a beer and believe that there is beer in the fridge, I get up and walk over to the fridge. When you kick my shin, I experience pain. What explains the tight correlations that exist between mind and body such as these? Spinoza's answer to this question, his parallelism doctrine, is also the basis of his panpsychism. The Parallelism Doctrine In proposition 7 of part 2 of the Ethics, Spinoza says: The order and connection of ideas is the same as the order and connection of things. This means that the mental realm and the physical realm are causally isomorphic. For every body there is an idea that represents it and for every idea there is a body represented by it. Moreover, there is a one to one mapping from causal relations between bodies to relations between ideas and vice versa. The reason Spinoza believes the parallelism doctrine is most clearly expressed in the following passage: Before we proceed further, we must recall here what we showed viz. that whatever can be perceived by an infinite intellect as constituting an essence of substance pertains to one substance only, and consequently that the thinking substance and the extended substance are one and the same substance, which is now comprehended under this attribute, now under that. So also a mode of extension and the idea of that mode are one and the same thing, but expressed in two ways. Some of the Hebrews seem to have seen this, as if through a cloud, when they maintained that God, God's intellect, and the things understood by him are one and the same. [...]Therefore, whether we conceive nature under the attribute of Extension, or under the attribute of Thought, or under any 1 Mcginn. 4 other attribute, we shall find one and the same order, or one and the same connection of causes, i.e., that the same things follow one another. That is, the parallelism follows from the fact that modes of thought and modes of extension are identical but conceived of differently. If they are identical, then they cannot differ with respect to their causal structure. This raises difficult questions about Spinoza's denial of mind-body interaction but they fall outside of the scope of this essay. Spinoza's Panpsychism Recall that for every body, there is an idea that represents it. Human minds are ideas of human bodies. These ideas are in Nature conceived of as a thinking thing. The human mind is thus Nature's idea of our body. Spinoza thinks that there is nothing special about the human mind. Just as the human mind is Nature's idea of the human body, the idea of any body whatsoever is the mind of that body. Spinoza writes: For the things we have shown so far are completely general and do not pertain more to man than to other Individuals, all of which, though in different degrees, are nevertheless animate. For of each thing there is necessarily an idea in [Nature], of which [Nature] is the cause in the same way as [it] is of the idea of the human Body. And so, whatever we have said of the idea of the human Body must also be said of the idea of any thing. (2p13s) This means that not only do human beings have minds, but also every part of the human body has a mind and every non-human body has a mind. In the case of non-human organisms that are reasonably complex, this result is more or less intuitive. Many people think that chimpanzees, dolphins, and even cats have minds. Perhaps more controversially, many people think that even less complex vertebrates have minds of some sort. But Spinoza extends the realm of the minded further to include invertebrates, plants, and even what we would classify as inanimate objects such as stars, planets, and tiny particles of matter. As the above text attests, Spinoza himself does not think that there are any truly inanimate objects. Everything has a mind, that is, is associated with an idea that represents it, and is to some degree alive. Degrees of Mentality Spinoza's thesis that each body has a mind, no matter how simple it is, raises several difficult questions. The first pertains to the relationship between the mind and intelligent behavior. In his Discourse on Method, Descartes claims that our evidence for mentality comes from intelligent behavior. According to Descartes, if some system can respond appropriately to an unlimited set of circumstances, then the causes of the behavior of that system are mental. For example, in competently using language, human beings can understand infinitely many novel sentences and in turn, can respond with infinitely many novel sentences. Thus we have evidence that human beings other than ourselves have minds. But if a system fails to exhibit such intelligent behavior, we have no evidence of mentality and attributing a mind to it would be unjustified. This is a plausible idea. Spinoza, on the other hand, attributes minds to systems that do not exhibit any 5 intelligent behavior such as stones, tiny particles of matter, and stars. What could justify him in doing so? Another difficulty stems from Spinoza's commitment to attributing minds to bodies that lack the degree of internal structure that we associate with mentality. For example, we observe a tight correlation between mental activity and the human central nervous system, which is very complex. We don't observe a tight correlation between mental activity and any more simple system. This strongly suggests that only physical systems with a high degree of internal complexity can have minds. Spinoza, however, is committed to attributing minds to any bodies whatsoever, no matter how simple they may be. How could he argue for the plausibility of such attributions despite the observed correlation between complexity and mentality? Two final difficulties comes from Spinoza's claim that not only the human body, but also every part of the human body has a mind that is a part of my mind. Every atom, every cell, every organ composing my body has a mind. What is more, each of these minds is a part of my mind. The first difficulty is that I seem to be unaware of a great deal that happens in my body. For example, my pancreas is currently producing insulin. If my pancreas has a mind and that mind is part of my mind, why am I unaware of this? The second difficulty concerns how these various minds can compose a greater mind, viz., my own mind. This is a difficult question because, it is plausible to think, under no circumstances do human minds ever compose greater minds of which they are parts. This strongly suggests that minds in general do not compose. Spinoza is aware of these problems. His response to the problems relating to intelligent action and complexity is to claim that all bodies are "to some degree" "animata." (1p13s) The word animata is generally translated as animate and although Spinoza does believe that all bodies are animate to some degree, I think the word is also meant to resonate with animus, which Spinoza uses as a synonym for mind (mens).2 Thus, Spinoza is saying that all bodies to some degree are alive and have a mind. The notion that the mental comes in degrees is crucial to Spinoza's claim that mind is pervasive throughout nature. It is more plausible to claim that stones and plants have minds if they have minds only to a very low degree than if minds are attributed to them without qualification. But what does it mean for mind to come in degrees? Part of Spinoza's account of what it means for bodies to be animate to different degrees is given in the following text: I say this in general, that in proportion as a Body is more capable than others of doing many things at once, or being acted on in many ways at once, so its Mind is more capable than others of perceiving many things at once, And in proportion as the actions of a body depend more on itself alone, and as other 2 See for example, 2a3. 6 bodies concur with it less in acting, so its mind is more capable of understanding distinctly. And from these [truths] we can know the excellence of one mind over the others.3 Spinoza thinks that some minds are more capable of perceiving many things at once than others are and also that some minds understand things more distinctly than other minds do. He claims that the ability of the mind to perceive many things at once is proportional to its body's ability to do many things at once and the ability of the mind to understand things distinctly is proportional to the extent to which the actions of the body depend upon the body alone. Why does Spinoza think that the mind's ability to perceive many things at once is proportional to the body's ability to do many things at once? The answer is found in Spinoza's account of sense perception and complex individuality. According to him, the primary content of the idea of the body, i.e., the mind, is the body itself. But when the body interacts with the external world, the state of the body depends not just on the nature of the body but also on the nature of the external causes that affect it. In this way, by representing the body, it represents a state of the body that carries information about the external world. The body's ability to acquire states that encode information about the external world depends upon its ability to do many things. To see why, we need to look at Spinoza's account of complex physical things like human bodies. A complex body such as the human body is defined by a pattern of motion that obtains between its parts. Such a body survives the changes it undergoes just in case the pattern of motion and rest that characterizes it is preserved. So if environmental inputs alter the motions of the parts of a complex body, that body survives the resulting changes so long as these new motions are incorporated into the body in such a way that its overall pattern of motion and rest is preserved. There are various ways in which encounters with external causes may be survived. A stone, for example, pursues a very simple strategy. It does one thing in response to all external causes: its parts remain bonded together and communicate the motions introduced in a more or less uniform way. Most significantly, it does not respond differentially to the way in which causal inputs from the environment are structured. For this reason, its states don't carry very much information about its external causes. But a human body pursues a much more complex strategy. In the response to external stimuli, it responds very differently depending on the structure of the stimuli. For example, while the stone is indifferent to anything but the total energy of the wave produced by the handclap, the human body responds differently depending on how that energy is structured. Wavelength, frequency, and amplitude all matter to the human body but not to the stone. In this way, Spinoza explains the seeming lack of mentality on the part of bodies that do not possess complex internal structure. Very simple bodies encode very little information about their external causes and thus the minds associated with them perceive very little about the external causes of their states. Very complex bodies encode much more information about their external causes and so the minds of those bodies perceive much more about their external environment. 3 2p13s. 7 Let us now turn our attention to the claim that the more actions depend upon the body alone, the more the mind understands distinctly. Spinoza thinks that causal responsibility is a degreed notion. This is intuitively plausible. Suppose that by myself I cannot lift an object that weighs one hundred pounds because I can only generate enough force to lift ninety pounds. I fully exert myself and you help by contributing the force needed to go from ninety to one hundred. There is a clear intuitive sense in which I am doing more of the work than you. If through resistance training I go from an ability to lift ninety pounds to an ability to lift ninety-nine pounds, then the next time we lift the weight together, and I fully exert myself, then I have contributed even more of the work.4 Spinoza thinks that most human behavior is partially explained by environmental inputs. This is clearly the case where sense experience guides action because sense experience requires environmental inputs. Spinoza also thinks that our cognitive behavior is purely rational only when environmental inputs do not explain it in any way. Spinoza is a rationalist who thinks that sense experience is the source of error and confusion, so we are at our cognitive best when our thinking is free from the influence of sense experience. We engage in rational thinking fully divorced from sense perception when we are doing pure mathematics and when we engage in pure philosophical reasoning. But although we are not perfectly rational when environmental inputs help determine our thoughts and behavior, we can still be more or less rational, depending upon how much our own nature contributes to the explanation of what we do and think. The more it contributes, the more rational we are. Spinoza relates structural complexity to power: the power of acting of a body and the correlative power of thinking of a mind are a function of complexity. Human beings are more capable of rational thought than, for example, fish or worms because their bodies and minds are so much more complex. Stones too have minds, but their bodies are even less complex than worms, and so they are, for all intents and purposes, incapable of rational thought. These conclusions help minimize the implausibility of attributing minds to creatures that lack the structural complexity that is correlated with mindedness. This also helps to solve the problem of how Spinoza can attribute minds to bodies that don't exhibit intelligent behavior. Because Spinoza associates power with complexity, very simple bodies do not have much power of acting just as their minds do not have much power of thinking. The minds of such creatures are nothing more than mute representations that generate few effects. However, when such representations join together to form complex wholes, new powers of thought are generated. And as a consequence of the parallelism doctrine, new powers of action in the body are also generated. Intelligent behavior is characteristic only of such complex bodies. It is sometimes alleged that Spinoza needs a distinction between (1) minds that are subjects of conscious experience and those that are not, and (2) ideas that are conscious and those that are not. The first distinction is needed because it is implausible to ascribe consciousness to, for example, stones because they lack the structural complexity that we associate with 4 I have adapted this example from Della Rocca, 2008, p. 115. 8 consciousness. The second distinction is needed because Spinoza is committed to the claim that the human mind contains an idea of every part of its body. But I am unaware of the action of my pancreas and many other events occurring in my body. Thus, if I have ideas that represent these things, they must be unconscious. It is further alleged, that Spinoza has no way of consistently making out any such distinctions. It is true that Spinoza cannot distinguish between conscious and unconscious minds, and conscious and unconscious ideas, but he has a related distinction that may serve just as well: he distinguishes degrees of consciousness. Spinoza links power and complexity to consciousness. Consider the following passage: [H]e who, like an infant or child, has a Body capable of very few things, and very heavily dependent on external causes, has a Mind which considered solely in itself is conscious of almost nothing of itself, or of God, or of things. On the other hand, he who has a Body capable of a great many things, has a Mind which considered only in itself is very much conscious of itself, and of God, and of things.5 We have already encounter the claim that a mind is more capable of perceiving more things at once and is more excellent, the more powerful its body is. Here the claim is extended to consciousness as well. The more powerful a body is the more conscious its mind is. Spinoza's remarks on consciousness are sketchy at best, but perhaps he could be read as describing a kind of functional account of consciousness. A powerful bodily state entails, by virtue of the parallelism, a powerful idea. An idea that is powerful contributes more to the determination of the mind's future states. That is, the idea contributes more to reasoning. This could be likened to a kind of access consciousness: an idea is conscious to the degree that it contributes to determining the direction of thought and contributes content to it. It seems, however, less compelling as an account of phenomenal consciousness. Because Spinoza links structural complexity with power and power to consciousness, stones are, due to their structural simplicity, conscious to only a very minimal degree. Likewise, thoughts about my pancreas do not determine my other thoughts to any appreciable degree. This suggests that they have only a very small amount of power. Consequently, they will be the subjects of only the dimmest conscious awareness. Thus, while Spinoza does not have the resources to draw a line between conscious and unconscious states and entities, he can place entities and states on a spectrum of consciousness. The last problem we have to consider is how minds can compose minds. Recall that the human mind is just Nature's idea of the human body. Spinoza tells us that the human mind is not special 5 5p39s. 9 in this regard and that we can regard Nature's idea of any body as the mind of that body. But the human body is composed of simpler bodies, each of which is represented by an idea in Nature's mind. Thus we must conclude that each idea of each part of the human body is a mind. The human mind is a complex mind each part of which is itself a mind. This might be regarded as implausible. To see why it seems implausible, consider the putative fact that human minds never join together to form more complex superhuman minds. Indeed it's very difficult to see how that could ever happen in principle. This could be taken as evidence for the principle that minds don't compose minds. But if we look at the details of how Spinoza thinks that simpler minds compose more complex minds, the account is not as implausible as it might first appear. To begin with, it must be emphasized that the human mind is not a substance, as it is for Descartes. Instead, Spinoza holds that it is a collection of ideas. In this way, it is not entirely dissimilar to the bundle theory of the mind familiar from Hume. The difference between the bundle theory and Spinoza's theory is that Spinoza adds the further claim that the ideas in the bundle compose a single complex idea. Thus, although it is strictly speaking correct to say that every part of the body has a mind, it's a bit misleading because Spinoza is deflating the mind not inflating ideas. The notion of a complex idea that is composed of simpler ideas is much more familiar (think of psychologically real complex concepts composed of simpler concepts), than the idea of complex minds composed of simpler minds. Spinoza just assimilates the latter to the former. Moreover, Spinoza denies the claim that human minds don't compose with other minds to form more complex minds. Indeed, he repeatedly asserts that the human mind is part of the infinite intellect which is the mind of the totality of finite corporeal creatures. Thus Spinoza clearly believes that his claim that the human mind has parts that are themselves minds is not in conflict with any general principles prohibiting minds from composing. Conclusion Spinoza believes that each body-every animal, plant, particle, and star-has a mind. Moreover, every complex body composed of simpler bodies has a complex mind composed of simpler minds. And just as bodies are modes of extended nature, minds are modes of thinking nature. Minds are thus Nature's ideas of the body. This view might seem to conflict with four plausible claims: (1) minds are possessed only by creatures capable of intelligent behavior; (2) minds are associated with only creatures with complex bodies; (3) we are unconscious of many things that happen in our bodies; and (4) minds do not compose. Spinoza responds to (1)-(3) with an account of degrees of power of thinking, which he associates with structural complexity. He is thus able to claim that although creatures incapable of any appreciable intelligent action and lacking structural complexity have minds, they have minds with very little power of thinking. And because he arguably has a functionalist account of consciousness, many ideas/minds will have very low levels of consciousness. With respect to (4), he assimilates minds to ideas and thus the claim that minds compose is no more implausible than the claim that ideas compose. Because many thoughts are complex, this is not implausible at all.