The Evolution of Consciousness

Representing the Present Moment

Paula Droege

• Verlag: Bloomsbury Academic
• Jahr: 2021
• ISBN:
  9781350166806
• Auflage: 1
• Thema: Philosophy
• Thema: Mind & Body in Philosophy

The Evolution of Consciousness brings together interdisciplinary insights from philosophy, neuroscience, psychology and cognitive science to explain consciousness in terms of the biological function that grounds it in the physical world. Drawing on the novel analogy of a house of cards, Paula Droege pieces together various conceptual questions and shows how they rest on each other to form a coherent, structured argument. She asserts that the mind is composed of unconscious sensory and cognitive representations, which become conscious when they are selected and coordinated into a representation of the present moment. This temporal representation theory deftly bridges the gap between mind and body by highlighting that physical systems are conscious when they can respond flexibly to actions in the present. With examples from evolution, animal cognition, introspection and the free will debate, this is a compelling and animated account of the possible explanations of consciousness, offering answers to the conceptual question of how consciousness can be considered a cognitive process.

1

In Defense of Function

Intelligence is based on how efficient a species

became at doing the things they need to survive.

Charles Darwin

Thinking about a Banana

The title of this chapter is an homage to Ruth Garrett Millikan’s article “In Defense of Proper Function” (Millikan 1989b) where she explains the importance of a historical, teleological description of mental representation. What it is to have a thought about a banana as opposed to an apple is for the banana thought to have served some function in relation to bananas. You need a banana thought to get bananas. Quite simple, really, although as we will see, the details get complicated quickly.

In the Introduction I suggested that a convincing solution to the explanatory gap will depend on a description of consciousness in terms of its function, specifically its function as a particular sort of mental representation. A critical card in the house of explanation is a theory of how representations might be constituted by physical states and processes. This chapter will show how several contemporary theories fail to adequately specify mental content; that is, they fail to explain why a thought is about a banana as opposed to an apple or a yellow fruit. The key feature, as the chapter title suggests, is identification of the function of representation as articulated in Millikan’s Consumer Theory. A number of objections to the theory will be addressed, as will the particularly difficult problem of qualitative character—the reds and stinks and clangs of conscious experience. The goal of this chapter is to show how physical vehicles like brains could come to have content like “banana” by serving the function of representing things in the world. Before we can understand the particular function of consciousness, we need a broader sense of the function of representation in helping an animal navigate its environment.

Note for nonspecialists: The two interludes and the objections in this chapter are fairly technical and aimed toward those with some background in the philosophical debates about these issues. These sections can be skipped if you are satisfied with the general explanation of how representation works. Try not to skip the whole chapter, though. The theories and arguments are not simple, but they are worth the effort to understand them.

Note for specialists: The arguments in this chapter sketch the reasons in favor of the views I advocate, but they are not comprehensive, conclusive, or particularly original. The point is not to convince opponents, it is to demonstrate how the Consumer Theory of representation forms the foundation of a solution to the explanatory gap. The original move is to show how the Consumer Theory supports a description of consciousness in terms of function, and that move requires at least some defense of function. For a fuller defense, see the authors and texts referenced.

A Potted History of the Mind-Body Problem

The word “representation” is used in many ways. Within philosophy of mind alone, there are numerous different theories of representation, and each defines the term in line with the theory. So take a moment to put aside your preconceived ideas of representation in order to see the particular problem about the nature of mind that a philosophical theory of mental representation aims to solve.

Prior to René Descartes, the standard way for Western philosophers to think about the mind and body was as two aspects or parts of a person. Plato conceived of a tripartite soul composed of spirited, appetitive, and rational parts, all of which operated to regulate the body. Aristotle took the soul to be the form of living matter; it is the capacity of the body to develop into the sort of thing it is. Even the medieval philosopher St. Thomas Aquinas took great pains to show how the soul is substantially unified with the body. Though the rational soul can continue to exist in heaven after the destruction of the body, Aquinas maintained that its nature depends on its capacity for action as a living animal.¹

Thinking of the mind as essentially separate from the body emerged with Descartes and Dualism, partly in response to Isaac Newton’s application of mathematical principles to the motion of bodies. If the body is regulated by physical law, the mind must be distinct from the body in order to be regulated by rational law. In the Meditations, Descartes reflected on the properties that seem to be essential to his mind and found that a mind is a thinking thing, entirely different from a body, which is located in space and has spatial dimensions (Descartes 1641). Even Descartes realized this stark division between mind and body failed to adequately address phenomena such as emotions that cannot be clearly split into a mental and a physical component (Brown 2006). Contemporaries of Descartes recognized that a deeper problem with mind-brain duality was causal interaction. If mind and body are separate, how does the body cause the mind to have ideas, and how does the mind cause the body to act?

And so the mind-body problem was born: how is the mind (essentially rational) related to the body (essentially physical)? One way to answer this question is to focus on the way ideas seem to be about things in the world. My ideas might be mistaken about the world, but there is undoubtedly the appearance of a world. There appears to be a banana, roughly two feet in front of me, resting on the table in a green kitchen with windows looking out on a grey winter day. Though the reality of these things may differ from the way they appear, their appearance is undeniable.

Fast forward 400 years and the mind-body problem has been transformed from a question of the relation between mind and body to a question of the relation between appearance and the world, or in representationalist terms, between representation and the object represented. When a banana appears to be on the table to my left, I represent the banana as on the table to my left. The task for the contemporary materialist is to explain how a brain (or whatever aspect of the nervous system is the appropriate vehicle) represents objects like bananas and tables, and how it comes to be accurate or inaccurate in its representations.

On What a Representation Is Not

To better understand how the problem of representation can be solved, we can begin by reviewing three popular theories that do not solve it: the Picture Theory, the Computational Theory, and the Causal Theory. Each theory offers a tempting but inadequate way of thinking about representation. We can avoid these tempting options by seeing where they go wrong.

The Picture Theory

First, the Picture Theory was the original and remains the most intuitively satisfying theory of representation. John Locke famously considered the mind a blank slate, a tabula rasa, and took ideas to be impressions stamped on the mind by objects.

These simple ideas, when offered to the mind, the understanding can no more refuse to have, nor alter, when they are imprinted, nor blot them out, and make new ones itself, than a mirror can refuse, alter, or obliterate the images or ideas which the objects set before it do therein produce. As the bodies that surround us do diversely affect our organs, the mind is forced to receive the impressions, and cannot avoid the perception of those ideas that are annexed to them.

(Locke 1689 Book II, Ch 1, §25)

The force of sensation gives the mind a picture that mirrors the objects that produced it. The Picture Theory seems right because it reconciles the recognition that the mind is separate from the world with the experience of full IMAX immersion in the world. On one hand, everyone knows that perception involves a relation to the world that may be mistaken. Illusions and hallucinations present the world in a way that it is not. On the other hand, the world appears to be immediately available; details of the branches and leaves outside my window are present in a way that feels direct. If my representations are pictures of the world inside my head, providing a kind of mirror image of my environment, then both the immediacy and distance of the world make sense.

Also worth noting is the way Locke describes perception as passive. The mind, in its blankness, awaits the impression of colors, sounds, and tastes. On the basis of this input, then, more complex ideas are formed, such as the idea of a tree composed of branches and leaves, which are in turn composed of simple color and shape ideas. Without the input of the senses, there would be no ideas at all, on this view. This commitment to sensation as a passive source of knowledge is the hallmark of Empiricism, which has been a significant influence in theories about the mind.²

Despite its intuitive appeal, however, the passive view of sensation is false, and the Picture Theory of representation fails. Research on implicit bias, priming, and other forms of cognitive influence on perception demonstrate that sensation is active.³ What we see is determined in large part by what we expect to see and what we need to see. This is a point about the operation of attention as well as the nature of perception. A wonderful illustration of the power of expectation was given by Dan Simons and Chris Chabris (1999). If you haven’t seen it already, google “selective attention test,” and follow the instructions on the video.⁴ Now for the spoiler: your expectation directs your attention to the people bouncing a ball, so you fail to notice the gorilla. When pursuing a goal, we are likely to see things that relate to that goal and miss unrelated things, even enormous and surprising things, like the gorilla. Our sensory system actively seeks out some things and ignores others.

Likewise, the Picture Theory fails both factually and logically. As a matter of fact, there is no place in the brain where a picture of the world is displayed.⁵ While it is true that patterns on your retina preserve the spatial relations of the visual scene (albeit upside-down), this is just the beginning of visual processing, and vision is just one sense. My representation of the world includes both sight and sound, and it is not clear what a picture of a sound (or a smell for that matter) would involve. Moreover, even the retinal pattern hardly satisfies the intuitions that support the Picture Theory. None of my neurons are yellow or banana-shaped, yet I see a yellow banana before me. The brain simply doesn’t picture the world in the way required by the theory.

As a matter of logic, the idea that representations are pictures before the mind implies that the mind is somehow looking at the pictures. If so, the mind must have inner eyes by which to view the picture and an inner mind to represent it. The inner mind must have yet another inner mind and so forth. This infinite regress shows that the Picture Theory cannot explain the mind, because it assumes there is a mind (with inner eyes) to see the picture.⁶

Picture theorists can avoid these problems by accepting the vehicle/content distinction discussed in the Introduction. They can then argue that sensations are brain vehicles (in other words, neurons) that represent yellow bananas, and do so simply by being the sensations they are. What it is for some neurons to represent yellow bananas and others to represent red cups is for there to be a covariation relation between the neurons and the things they represent. Neurons “picture” bananas when the neuron pattern changes in relation to the banana’s movement, shape, color, etc. No inner mind is required to see the sensations, so long as the neurons match the object in the appropriate ways. The picture is a mirroring relation rather than a mirror image. At this point, though, it is unclear that the neural “picture” bears much resemblance to the photographs and paintings that inspired the Picture Theory.

Moreover, there is a deeper problem. Picture Theories are committed to Indirect Realism, the view that the mind represents the world by means of representing sensations. When I see a banana, I am actually seeing my mind’s picture (or representation) of the banana. I then infer that there is actually a banana in the world causing this picture. My sensations appear immediately before my mind, but the object causing these sensations is only known indirectly. What if I am wrong? Worse yet, what if I am massively wrong?

One of the most fun and familiar philosophical mind games is to wonder whether everything we sense could be caused by something other than the real world. A current version of the game involves being snatched by clever neuroscientists who put your brain in a vat wired to simulate the world. Instead of a banana causing my banana sensations, the vat produces electrical signals that are indistinguishable from a banana.

Here is one of the first tests of an adequate theory of representation: the Vat Test. Remember the challenge is to figure out how a brain represents objects like a banana. On a Picture Theory, neurons picture or match the banana. If my brain were in a vat—or a matrix or a dream—the neurons might be in the same pattern as they would be when there is an actual banana. For the Picture theorist, all there is to representing the banana is to be in the “banana” brain state, whether or not there are or ever have been real bananas. This means that my brain might right now be in a vat and so I cannot know if there is anything that my brain state truly represents. More troubling, this radical skepticism renders the existence of bananas irrelevant from the internal perspective of the picture. The banana would look the same no matter what the situation outside of my brain.

In my view, this result fails the Vat Test. While the possibility of hallucination and illusion must be explained, a theory of representation should first and foremost connect banana representations to bananas. The object should determine representational content in such a way that absence of the object makes a difference to the representation in some way. Either the representation is false or has no content at all. If representational content would be exactly the same in a vat, then the theory is not an adequate theory of representation. My point here is not that it is impossible for me to be a brain in a vat; I address skepticism later in the chapter. The Vat Test indicates whether there is a meaningful relation between the representation and the object it represents. Because my banana representation would have the same meaning, even if there were no bananas, the Picture Theory fails the test.

Metaphysical Interlude: Representation and an Alternative to Reduction

Intuitions differ on this point, which is why materialists sometimes favor the Picture Theory. In the Introduction I mentioned that materialists take mental states to be constituted by physical states. As Lynne Rudder Baker puts it, “every concrete particular is made up entirely of microphysical items” (2009: 110). Reductive Materialism makes the further claim that higher-order properties and relations, like mental states and their causal powers, can be entirely explained in terms of microphysical properties and their relations. That is, given a set of physical properties, the mental properties that are instantiated follow as a law of nature.

So, on Reductive Materialism, any brain that is microphysically identical to your brain right now would necessarily have the thoughts and sensations you are currently having, even if that brain is in a vat. Bananas can have no essential role in determining the content of your banana experiences, because you could have exactly the same experiences even if no bananas exist. The best you can hope for is that your internal picture of a banana somehow matches something in the world that relates to yellow-colored, banana-shaped things.⁷

It may seem that Non-reductive Materialism is an oxymoron. A commitment to Materialism may seem to entail that only physical properties have any metaphysical status; anything other than properties described by physics has at best a nominal status, a kind of shorthand for referring to collections of microphysical particles. Without canvassing the array of positions and arguments, let me motivate the possibility of Non-reductive Materialism with a sketch of Baker’s Constitution View.

The task is to provide a connection between mental and physical properties that avoids two problems posed by Dualism, the view that the mind is a different sort of stuff or property from physical properties. The first problem is the possibility of zombies, physically identical beings that are not conscious. Because we can imagine zombies, Chalmers (2010) argues, the nature of consciousness must be distinct from, albeit systematically connected to physical structures. To avoid zombies, a materialist theory needs to describe how mental properties depend on physical properties in a sufficiently determinate way.⁸

The possibility that mental properties are caused by physical properties but do not themselves have any causal power is the second problem, posed by Epiphenomenalism. Your experience of the red of the stop sign is caused by the neural activity in your visual system, according to the epiphenomenalist, but the redness plays no role in your response. The neural activity alone cause...