Consciousness, Self, and the Prefrontal Cortex

cartesian-theater

There is a basic question that must be addressed when pondering the nature of consciousness, and that is: why have consciousness at all? The brain processes a great deal of information below the level of conscious awareness, from visual to auditory to tactile, and then the integration of all of these before they can be brought into conscious awareness. Yet conscious awareness itself seems much more limited in the amount of information that it can handle at a time—5 to 9 “chunks” of information, at a time, it would seem. So why rely on conscious awareness as heavily as we do? It certainly seems, at least from this angle, much less able than non-conscious processing—yet, given its apparent efficacy in raising humanity to the heights of culture and insight that we enjoy today, it surely has something essential to offer us.

The prefrontal cortex is the latest structure to appear in the evolution of the brain, and is the structure that shows the greatest development between humans and our closest biological relatives. Furthermore, it is known to mediate a great deal of the abilities considered distinctly human, such as planning, reflection, and empathy, all of which apparently require conscious awareness. Surprisingly, however, a vast abundance of the projections that the prefrontal cortex sends back to more primitive, sub-cortical structures are inhibitory—they function largely to suppress activity in these regions. In fact, this has led several researchers to rethink the concept of free will and, somewhat amusingly, refer to it rather as “free won’t,” in that we are mainly choosing what not to do, of all of the responses recommended by sub-cortical structures. And this is where we might find a reason for conscious awareness.

Consciousness relies on a crucial ingredient for dealing with the world in the way that the prefrontal cortex specializes in doing: it removes behavior from the moment-to-moment sensory perceptions incessantly presenting themselves to sub-cortical brain regions. Instead of constantly responding to each and every stimulus as it comes in, consciousness introduces a disconnect that allows reality apart from oneself to be treated as perceived, and thus distinct from the self and manipulable. Non-conscious responses don’t require perception in the same way that conscious processes do. In order to consciously ponder a course of action while planning, you need a virtual representation to work with, and in order to do that, you need some distance between yourself and the object being represented. Every day perceptions such as the visual field in front of you may function in a very similar manner: a stimulus presents itself, is processed by sub-cortical structures, and then a course of action is offered up to conscious awareness to be chosen or discarded by conscious reflection. There is a whiff of “opponent processing” going on in this narrative, something that comes up a lot in systems biology: two structures working in opposite directions in order to better center around a single desired outcome. Non-conscious, sub-cortical processing is largely reactive, leading to sometimes extreme, reflexive responses; conscious prefrontal processing, on the other hand, divorced from the constant demands of the environment, is more receptive to multiple courses of action, but can sometimes leave us unable to settle on an alternative. With the two of these working with opposing aims, however, behavior that is reactive enough to survive, but receptive enough to be a functioning member of society, can be attained.

This is far from a coherent theory or hypothesis, but the parallels between the roles of sub-cortical and non-conscious processes on the one hand, and prefrontal and conscious processes on the other, along with the connections between the two, are surely going to be important in mapping human consciousness.

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Memory and Personal Identity

Today in metaphysics I had to write up an impromptu response to the question: “Is memory important to Personal Identity?” I only had thirty minutes to write and not much time to prepare, so it’s a little rough, but I am nonetheless satisfied with what resulted, so I’ve reprinted it here:

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Memory is not vitally important to personal identity. This is not to say that it is not useful to our everyday determination of “who’s who,” more on that later, but we can show that it is possible to maintain personal identity without maintaining memory.

Consider the case of Tom, or case 1. Tom is about to be tortured. But the torturer, being a slightly nice guy, proposes the following: before torturing Tom, he will wipe all of Tom’s memories. Should this make Tom feel any better? “Of course not,” I would expect Tom to reply, “I’ll still be tortured, I just won’t remember that it’s still me who was tortured!” So we are not making the situation any better—we are actually making it worse! Not only are we going to torture Tom, we are also going to turn him into an amnesiac! If this case is persuasive, then we have shown that memory is not necessary for personal identity.

But I think we can go one step further and show that it is not sufficient either. Consider case 2: Exactly the same as before, except this time we will not merely erase Tom’s memories, but instead transfer them to another body, say, Jane’s body. Now, who would Tom, pre-memory transfer, want us to torture, Tom’s body or Jane’s body? I think that, thinking only of himself, he should want us to torture Jane’s body, and here’s why: this case is no different from the first. If removal of memory is not enough to remove personal identity, as the case 1 seems to show, then how could implantation of memory create a person? If it were able to do so, then we would have two “Toms” at the end of the procedure: one amnesiac Tom in Tom’s body and one “normal” Tom in Jane’s body—but this seems to be obviously mistaken, Tom can only be in one place at a time! So which Tom is illusory? Well, if we stick with our judgment for case 1, then it seems we have to say that the “Tom” in Jane’s body is the illusory one. It’s not really Tom, Jane just thinks that she is Tom. Tom is still in Tom’s original body. If all of the preceding is true, then we have shown that memory is neither necessary nor sufficient for personal identity.

At this point, it would be prudent to evaluate just what it is that we are saying, and just what we are not saying. The preceding argument aims to show that memory is not important from a metaphysical standpoint—but this says nothing about the epistemic standpoint. In real life, memory is often all that we have to go on for determining personal identity. How do I know that I am the same person as I was last week? Because I have the memories of what I did last week! If we agree with the preceding argument, though, it would seem as if we were contradicting ourselves. We cannot determine our own identity based solely on our memories. Well, okay, maybe we can’t, for all we know, some mad scientist  implanted some false memories into my brain while I slept, and I am not who I think I am, this is not outside the realm of possibility. But it seems pretty unlikely—so, inferring to the best explanation, that barring unusual circumstances memory goes hand-in-hand with personal identity, I conclude that I am most likely the same person as my memory tells me I was last week. It’s not certain, but it is very likely. It’s important to note here, though, that these are all epistemic worries. They tell us nothing about the metaphysics of personal identity. I can use memory as a good “indicator” of personal identity, so in that sense it is very important to our conception of personal identity, but that does not mean that the two are inextricably linked. As an analogy, if I hear a dog bark, I usually infer  that a dog is nearby, but for all I know someone is merely playing a recording of a dog’s bark and there is, in fact, no dog nearby. Personal identity refers to the dog, and the recording of a bark is the memory of Tom in Jane’s body.

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There’s a technical point about memory that I did not have time to address in my original response, but which I want to bring up here. In order for something to really be a memory, it has to stand in a causal relation to the event that it recalls—that is, the event that it recalls has to itself be what caused the memory to exist. So in this sense, I probably have many things that I would call “memories” in my head that are not truly memories. Perhaps I am misremembering something, or perhaps I have heard a story of my childhood so many times that, even though unbeknownst to me my own memory of the event is gone, I have recreated the scene in sufficient detail for me to be able to picture it vividly. On this definition of memory, Jane never really had memories of Tom’s life. They felt like memories to Jane, but since they were not caused by the events in Tom’s life, but rather by the torturer’s memory implantation, they are not, in this strict sense, true memories. If you were to adopt this more nuanced view of memory, then a memory theory of personal identity may be more plausible. Unfortunately though, you can still show, as per case 1, that memory is not necessary for personal identity.

Conversations on Consciousness

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Since the spring semester is now in full swing, it has been increasingly difficult for me to devote the necessary time to a full-length treatment of consciousness as I would like. This in mind, I picked up a copy of Susan Blackmore’s Conversations on Consciousness the other day, and I have not regretted it. It serves as an informal introduction to several competing theories and views on the scientific study of the brain and conscious experience. The set-up of the book is simple: interviews with the researchers/philosophers themselves explaining their theories in their own, colloquial way. Add to this a few questions on free will and the fate of consciousness after death, and you get twenty of the most interesting conversations that I’ve ever had the pleasure to read. They allow, among other things, the chance to see these researchers as actual people, and not simply as objective reporters of experimental results as happens far too often.

I have only one complaint about the book, which you may have guessed given the author, Susan Blackmore. Put simply, Blackmore endorses a few very fringe (and some, myself included, would say absurd) ideas about the nature of consciousness. Normally, this would not be an issue—everyone is entitled to their own opinions, and I often disagree with the authors that I read. The complaint comes, however, in the questions that Blackmore chooses to ask her interviewees. The book is accompanied by the sub-script, “What the Best Minds Think about the Brain, Free Will, and What it Means to be Human.” At times, though, it seems like it would read more accurately as, “What the Best Minds Think about My Ideas about the Brain, Free Will, and What it Means to be Human.” This is not over-riding, and most of the time the book stays true to its stated purpose (I thank the interviewees for most of this, they do a good job sticking to what they believe are the real issues), but it is, at times, distracting. It is not enough to knock this down as a great book, well worth reading, but it is something that should be noted, nonetheless.

I would like to give this five out of five stars—it was great fun to read—but the above complaint makes me unable to do so. That said, I would give the interviewees five out of five stars and Blackmore four out of five stars, so let’s say that the book as a whole gets four and a half out of five stars.

Minds, Brains and Science

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John Searle’s Minds, Brains and Science is a collection of the six Reith Lectures that he gave in 1984 on the relation between our conscious, meaningful, phenomenal experiences and the backdrop of nonconscious, meaningless, objective physical reality against which all of the former inevitably play out. Essentially, the problem is this: We experience things, but everywhere else we look in the universe, we do not see experiences. How do we explain this seemingly trivial fact and make consciousness fit in with everything else we know?

This is inevitably a question that he is unable to provide a clear answer for, but, nonetheless, this was a successful, and worthwhile, work. The lectures were intended for a lay audience, so they are largely non-technical, but as far as I can tell, none of the necessary content was lost. Searle is still able to explicate each of the sub-problems and arguments very well. He manages to minimize caricaturing his opponents while simultaneously keeping the focus on what, he thinks, are the real issues. All the while, he manages to introduce several new ideas. His remarks on the social sciences and the freedom of the will are especially noteworthy.

In its entirety, the read comes down to less than a hundred pages, making it a perfect introduction to the problem at large. At the same time, it retains enough depth to catch the eye of even the most weathered philosopher-scientist—and for that, I give it five out of five stars.

Determinism, or Indeterminism: That is not the question.

In my Metaphysics class today, the following argument was put up for scrutiny:

1) If determinism is true, then no one acts freely, ever.

2) If indeterminism is true, then no one acts freely, ever.

3) Either indeterminism is true, or determinism is true.

4) Therefore, no one ever acts freely, ever.

5) If no one ever acts freely, ever, then no one is ever responsible for their actions.

Premise 1, in brief, relies on that assumption that if the world is deterministic, then everything that happened today was a necessary consequence of what happened millions of years ago. If everything that happened today was a necessary consequence of events in the distant past, then no person has any control over the present—it is all set in stone, as it were. Free will dictates a certain amount of control over present actions, so if this control is absent, then so is free will.

Premise 2, on the other hand, relies on a purely probabilistic definition of indeterminism. If events are indeterministic, which is to say that they are merely an odds game with event A having a 40% probability, and event B having a 60% probability, then we still lack any sort of “control” over the situation. Which event occurs is largely arbitrary, relying only on some unknown odds, written in the sky or otherwise.

This is not to say that these are the only ways in which premises 1 and 2 can be formulated, but this is how they were presented in this case.

Most of the objections raised, both in my class and in the literature, from what I’ve seen,  have attempted to disprove either premise 1 or 2. That is, there can be free will under determinism, or there can be free will under indeterminism. Most of these amount to some re-formulation of free will. I will not be taking either of these positions. Instead, I will attack premise 3: That the world is either deterministic or indeterministic.

The core of my argument rests on the claim that premise 3 presents a false dilemma. It is either determinism, or it is indeterminism, but not both. I assert that it is, indeed, both, or at the very least, we are not in a position to rule this possibility out. Current physics, which is where most of these theories claim to have their support, does not itself claim to have sorted this issue out. We know that under certain circumstances, such as when the scale is microscopic, that the world behaves in an apparently indeterministic way. Under other circumstances, such as when the scale is macroscopic, the world behaves in an apparently deterministic way. Many propose that we can link these two, and show that it is really one, and not the other, in virtue of a fundamental property of nature: namely parsimony—or, that the universe is, at its most fundamental, simple (simple in the sense that it all can be reduced to more or less the same thing). But, what they miss, is that it does not have to be this way. There is, in fact, no law that says that the universe must be simple. It may very well turn out that the universe is complicated, perhaps even too complicated for us to understand it, in the proper sense of the word.

(The following is mere speculation, I have absolutely no empirical basis for the ideas that follow; however,  I still, personally, find a great deal of plausibility in them, but you have been warned, nonetheless!)

Building off of this, and the fact that most of the arguments that place free will either in a purely deterministic or a purely indeterministic light typically have to resort to a reformulation of free will itself, I now assert that free will is only a coherent construct in a world that is both deterministic and indeterministic. What I propose is the following, which relates this more specifically to the theme of this blog: free will can only exist in conscious creatures. This may seem unnecessary to state in so many words, but the following should provide reasons for it. Complex brains are, in a general sense, specialized organs for planning and deliberation. Given that the microscopic events of this world are largely indeterministic, and that the macroscopic events are largely deterministic, we can postulate the following: brains serve to make sense of a vast multitude of indeterminacy. Through the process of evolution, and, to steal a phrase from a neuroscientist I once knew, thanks to the goddess of molecular evolution, they came to be in a position to turn underlying indeterminacy into coherent, conscious actions. This is not an appeal to a “collapse-of-the-wave-function” view of consciousness, to be clear. Rather, it is an attempt to reconcile the disparate aspects of reality into one coherent framework.

We can use this argument to strike down some of the objections raised to both purely deterministic and purely indeterministic accounts of free will. One variety of the former asserts that if you could not have acted otherwise, then you could not have acted freely, as stated above. If there is some underlying indeterminacy, however, this is clearly not the case. There are, in fact, a multitude of different ways in which you could have acted. Aha! But this just reduces to a variety of the argument from indeterminacy—that actions are merely arbitrary instantiations of probabilities, right? But that is where the deterministic aspect of reality kicks in. Once the most basic underlying facts about the world are set, in a probabilistic fashion, then determinism takes over. For this, I draw on an idea put forth by John Searle: downward causality, but in no way do I claim to restate his argument. The higher-order functions of the brain, namely consciousness, do indeed have “causes” that exist as smaller, microscopic bits, but these higher-order functions also have the ability to rain down causation on these smaller bits, much in the way that higher-order theories of economics can influence the activities of lower level commodities. Neither of these can be “smoothly reduced,” as Searle puts it, to the other, but that does not imply that one or the other does not exist, or play a meaningful role. In fact, Searle says that typically, reduction of one thing to another serves the purpose of showing that one of those things does not exist, not the other way around, as is often claimed.

This may seem counter-intuitive, and in some ways, it does have to re-formulate the popular idea of free will. In particular, it draws a distinction between free will at its most basic on the one hand, and conscious will on the other. Conscious will, or the idea that you are consciously in control of all of your actions and thoughts, is inevitably false. A handful of psychological experiments demonstrating non-conscious biases and predispositions shows this very simply. But this is not what we are talking about when we say free will, or so I claim. Free will is much more general than the limited definition of conscious will. At its most basic, it requires that you be capable of acting in certain ways that rely on intentional stances. Even if you are not consciously aware of your decisions to act in certain ways, it is still you that is making them. You are your brain, and everything that comes along with it. Simply because something is non-conscious does not make it any less a part of you. It may clash with the popular account of who you are, but at the end of the day, you are made up of more non-conscious pieces than conscious pieces, so restricting our definition of free will to the conscious pieces seems to make little sense. Now, this is not to say that our conscious feeling of free will is irrelevant, but it is a different matter to bring up—specifically, it is more of an epistemic question than a metaphysical question.

Musings on Consciousness

When it comes to consciousness, I assume two fundamental notions:

1) The first I borrow from David Chalmers, which runs along the lines that we must be “taking consciousness seriously.” By this, I mean that I assume that it exists, thereby ruling out the possibility of eliminativism. I also take this to mean that consciousness is not merely an “illusion,” as the fact of experiencing it directly seems to show—it is the only fact that we can ever know directly. Relatedly, conscious experience is the only phenomenon in nature so far that seems to have a first-person aspect. Everything else can, arguably, be explained or described fully in third-person terms, but to explain consciousness in this way leaves out a fundamental aspect: that it is experienced. This may eventually prove to be false, but at the least, it suggests that we may need to adopt a radically different explanatory strategy.

2) I assume that conscious experience is not merely epiphenomenal. In other words, I am assuming that conscious states have some ability to act as causal agents to guide behaviour, and that behaviour and consciousness are not both results of some other non-conscious process. How this will play out, I do not yet know, but to deny that conscious states have some causal purpose seems to miss the point and run directly against phenomenal experience. However, if it turns out that conscious states are not causal agents, and sufficient arguments can drive that point home, I’ll have to learn to live with it. In the meantime, I’ll retain my current stance, as it seems to me to be a logical foundation to build off of. An interesting avenue I have recently stumbled upon has suggested a fundamental link between causality and consciousness, in the sense that consciousness allows causality to be “realised,” in a sense. Rosenberg discusses this idea, so I will be investigating that possibility first. Other avenues will be investigated in time if this proves to be a dead end.