Tag Archives: Philosophy of Mind

A Guide to Reality, Part 12

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Chapter 7 of Alex Rosenberg’s The Atheist’s Guide to Reality is called “Never Let Your Conscious Be Your Guide”. A more grammatical title would have been “Never Let Consciousness Be Your Guide”. A longer but more accurate title would have been “Never Let Introspection Be Your Guide to What’s Happening in Your Mind”, because that’s the actual theme of the chapter: “Scientism requires that we give up everything introspection tells us about the mind” [147].

As he often does, Rosenberg overstates his case, apparently for rhetorical effect. After all, is it really true that introspection is a completely unreliable guide to what’s going on in our minds?

He offers as evidence three kinds of phenomena. The first is “blindsight”. Researchers have discovered that people with certain kinds of brain damage can perceive features of the world without being conscious of what they’re perceiving. For example, a person with a particular kind of damage to the visual cortex, who denies seeing anything at all, can “see” colors and shapes and even the expressions on other people’s faces. If asked whether they see something, they answer “no”, but forced to guess, they give the correct answer. Here, then, is a case in which conscious introspection, which indicates that I don’t see anything, is unreliable, because I really do.

Rosenberg’s second piece of evidence concerns our common belief that we have free will. Most of us are quite convinced that we make conscious decisions that result in freely-chosen actions all the time. However, experiments suggest that when we decide to perform a random action like moving a finger a certain way, the physiological process that will inevitably lead to the action taking place is underway before we’re aware of our decision to perform the action. 

The most interesting case he cites is one in which a neuroscientist stimulates a subject’s brain, causing the subject’s finger or wrist to move but also causing the subject, milliseconds later, to claim that the motion resulted from the subject’s conscious decision.The interpretation of these findings and their relevance to the free will problem are controversial, but they do suggest that conscious decision-making may not be as important in making decisions as we think it is.

Finally, Rosenberg argues that the existence of optical illusions shows that consciousness is unreliable. We interpret visual stimuli according to unconscious rules of thumb (mixed metaphor). These rules of thumb, which are probably the combined product of human evolution and our own experience, often mislead us. The circles in the diagram below look different but really aren’t, so here’s another case, according to Rosenberg, in which we shouldn’t let consciousness be our guide. (The book includes some interesting illustrations from the Purves Lab, which are available here.)

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Chapter 7 is relatively brief, because in this chapter Rosenberg is laying the groundwork for an especially counterintuitive idea he’s going to discuss in the next chapter (that we don’t actually think “about” anything at all). For now, here’s his conclusion:

We have seen that consciousness can’t be trusted to be right about the most basic things: the alleged need for visual experiences to see colors and shapes, the supposed role of conscious decisions in bringing about our actions, even the idea that we [see the world as it is]. If it can be wrong about these things, it can be wrong about almost everything it tells us about ourselves and our minds [162].

An important thing to note regarding Rosenberg’s argument is that he isn’t really claiming that conscious sense perception is completely unreliable (at least that’s not what I think he’s claiming). Although he denies that colors, for example, are mind-independent properties, he clearly believes that we do learn about the world using our eyes and ears. Otherwise, it would be odd to offer evidence that a blind person can perceive the “correct” color of an orange and that optical illusions are illusory (compared to what?). It would also be difficult to explain why most of us navigate the world better when our eyes are open and we’re not wearing headphones.

His principal thesis in this chapter is that certain conclusions we naturally draw from introspection (“the examination or observation of one’s own mental and emotional processes”) are mistaken. Specifically, it’s natural for us to assume that we need to be conscious in order to perceive certain features of the world, that our choices clearly determine our actions, and that (prior to being let in on the secret) we can always tell whether two lines are the same length or two circles are the same color just by looking.

I think Rosenberg is wrong, however, when he concludes that introspection can’t be trusted about “the most basic things”. What are the most basic conclusions we can draw from introspection? I’m not sure about that, but some natural conclusions seem more basic than the ones Rosenberg criticizes.

For example, we are better at perceiving features of the world when we’re relatively conscious (like when we’re awake) than when we’re relatively unconscious (like when we’re asleep). Some people see and hear better than others. Sight is usually reliable, even though there are occasional optical illusions. And when we feel angry or sad, we are generally angry or sad. It’s just wrong to think that introspection is always wrong about the most basic things.

I won’t offer a more basic conclusion about free will, except to say that conscious deliberation seems to help in making some decisions (whether to enroll at a college, get married or buy a house, for example) – whatever the underlying physiological processes are. Rosenberg may be right that conscious decisions are always the aftermath of unconscious decisions. We never really know what decision we’re going to make until it starts to “feel” like the right decision or we actually do something. Maybe our brains always do the necessary work unconsciously right before we discover what we’ve decided.

Coming up (sooner or later), part 13 of “A Guide to Reality”: Is it true that the brain does everything without thinking about anything at all?

The Conscious Mind: In Search of a Fundamental Theory by David J. Chalmers

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The Conscious Mind is one of those philosophical works that becomes famous because it features interesting arguments in support of implausible conclusions. Chalmers argues for property dualism, the thesis that mental properties are fundamentally different from physical properties. In other words, mental states are not equivalent to, cannot be reduced to, and do not logically supervene on brain states. This is a more plausible view than the traditional dualist claim that there are mental substances (minds or souls) in addition to physical substances, and that the mental and physical substances somehow interact.  

Chalmers agrees that there are psycho-physical laws that relate brain states and mental states, but argues that physical properties and mental properties are ontologically distinct. Maybe this is the correct view, but Chalmers goes further when he begins to discuss a possible fundamental theory of consciousness. He thinks that we should ascribe consciousness to any system that exhibits the same causal relationships as a brain, e.g. automated systems, John Searle’s Chinese Room translation scheme, and Ned Block’s billion minds linked together by radio. Since he views consciousness as a fundamental property of the universe, he thinks that rocks and even sub-atomic particles might possess some simple form of proto-consciousness. He suggests that panpsychism is a real possibility. He also argues that the simplest interpretation of quantum mechanics involves minds branching into other minds, so that each of us is one of a vast set of similar minds, all having split off from our infant selves.

The naturalistic or property dualism that Chalmers advocates, featuring “physical properties, separate phenomenal properties, and a lawful connection between the two”, is certainly worth considering as a philosophical theory of mind. If a property is merely a way of being, maybe mental properties (what it is like to have experiences or to be an X) are fundamentally different from physical properties. However, his views on what systems or objects might be conscious are much less plausible, despite the many ingenious arguments that he offers.  (7/25/11)

Empiricism and the Philosophy of Mind by Wilfrid Sellars

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This is actually a long essay, which I read in a collection of essays by Sellars called Science, Perception and Reality. But the essay has been published separately as a book, with an introduction by Richard Rorty and study notes by Robert Brandom, and since I’ve read that introduction and those notes, I’m listing Sellars’s essay as a book.

More to the point, “Empiricism and the Philosophy of Mind” is an attack on what Sellars calls the “Myth of the Given”, his term for the view that our knowledge of the world is based on basic or foundational beliefs, and that we derive such basic beliefs from what is “given” to us by sense perception. In particular, Sellars focuses on the philosophical theory that our fundamental knowledge of the world is knowledge of sense data.  Sense data are thought to be the particular impressions that we are aware of when we perceive the world. According to this theory, when I perceive a red apple, for example, I actually experience a red expanse of color, which may or may not represent an actual physical object. Philosophers who accept the sense data theory believe that our knowledge of the world rests on the foundation provided by such sense data.

Sellars criticizes this view in various ways, for example, by arguing that language about how something appears to us (like the language of sense data) is logically dependent on language about how things actually are (like the language of physical objects). Sellars also argues that the sense data theory fudges the clear distinction between non-cognitive impressions (sentience) and cognitive beliefs (sapience) — beliefs belong to the “space of reasons” and sense impressions don’t. In sum, “one could not have observational knowledge of any fact unless one knew many other things (i.e. had the relevant concepts) as well”.  In Brandom’s words, “one can’t think until one has learned to speak”, and one can’t speak until there is a community of speakers engaged in the social practice of speech (which includes giving and asking for reasons).

The last part of the essay is devoted to his own myth, which is supposed to explain how human beings came to talk about sense impressions in an intersubjective way, as theoretical entities. I didn’t find Sellars’s arguments or explanations convincing enough to rid me of the urge to take sense data or foundationalism seriously. But this is a difficult work that seems to deserve detailed study.  (10/13/10)