Category Archives: Philosophy of Mind

A Harvard Medical School professor makes the case for philosophy

In a recent op-ed in the Washington Post Dr. David Silbersweig made the case for the value of a liberal arts education and in particular a philosophy education. Dr. Silbersweig is the Chair of the Department of Psychiatry and Co-Director of the Institute for the Neurosciences at Brigham and Women’s Hospital, and Stanley Cobb Professor of psychiatry and Academic Dean at Harvard Medical School. As a professional philosopher I found his piece interesting and I’d like to summarize his piece and comment on it.
Silbersweig begins by remembering how much he enjoyed being an undergraduate philosophy major and how philosophy,

has informed and provided a methodology for everything I have done since. If you can get through a one-sentence paragraph of Kant, holding all of its ideas and clauses in juxtaposition in your mind, you can think through most anything. If you can extract, and abstract, underlying assumptions or superordinate principles, or reason through to the implications of arguments, you can identify and address issues in a myriad of fields.

Originally drawn to issues in the philosophy of mind, he quickly realized that he needed to study the brain to understand the mind. And wanting to help those who suffered mentally, he realized the need to study medicine. Philosophy had led him to his profession. Moreover his interest in Eastern philosophy, “with its focus on the development of the mind to achieve well-being” led him to study behavioral neuroscience and eventually to the study of both psychiatry or neurology.

Further study abroad confirmed that specialists “without a liberal arts foundation, while often brilliant, generally had a narrower perspective.” But those with such foundations had “certain insights and nimbleness of thought” that those whose training was more vocation did not. Now Silbersweig has come full circle. “Through studies, writings, and symposia, I have been able to bring the knowledge and perspective of my fields to timeless and timely problems in philosophy of mind, including free will, consciousness, meaning, religious experience and self.”

His recent experience teaching “an advanced philosophy of mind seminar at Harvard,” led to the realization of how much his scientific training aided students who posed sophisticated philosophical questions but who “were unknowingly misguided by virtue of being under-informed by data.” So philosophical inquiry is valuable, especially if scientific truth informs it. To solve the most desperate problems facing our world, we need minds that find novel solutions, mind informed by both philosophy and science. As Silbersweig concludes:

We need to foster and protect academic environments in which a broad, integrated, yet still deep education can flourish. They are our national treasure and a strategic asset, whether some politicians would recognize that, or not — and philosophy is foundational, whether my old dentist would appreciate it or not.

Reflections – All of this reminds me of lessons I learned from my mentor in graduate school, Richard J. Blackwell. Professor Blackwell,  who had done graduate work in both philosophy and physics, told me that  good philosophy must be informed by science. Dr. Silbersweig piece also reminded my of the work of Jean Piaget, who in his book, Insights and Illusions of Philosophy, wrote:

It was while teaching philosophy that I saw how easily one can say … what one wants to say … In fact, I became particularly aware of the dangers of speculation … It’s a natural tendency. It’s so much easier than digging out facts. You sit in your office and build a system. It’s wonderful. But with my training in biology, I felt this kind of undertaking was precarious.1

Philosophical speculation raises questions, but it cannot provide answers; answers are found only in testing and experimentation. Knowledge presupposes verification, and verification attains only by mutually agreed-upon controls. Unfortunately, philosophers do not usually have experience in inductive and experimental verification. As Piaget put it:

Young philosophers because they are made to specialize immediately on entering the university in a discipline which the greatest thinkers in the history of philosophy have entered only after years of scientific investigations, believe they have immediate access to the highest regions of knowledge, when neither they nor sometimes their teachers have the least experience of what it is to acquire and verify a specific piece of knowledge.2

But how did it happen that philosophy became so separate from the scientific method? Piaget traces this separation to the 19th century, when philosophy came to believe that it possessed a “suprascientific” knowledge. This split was disastrous for philosophy, as it retreated  into its own world, lost its hold on the intellectual imagination, and had its credibility questioned. For Piaget, philosophy is synonymous with science or reflection upon science, and philosophy uniformed by science cannot find truth; at most it provides subjective wisdom. In fact, philosophy is not even about truth; it is about meaning and values.

But while philosophical speculation without scientific understanding is limited, so too is vocational or scientific understanding uninformed by philosophical understanding and reflection. And this is ultimately Silbersweig’s point. One can take blood pressure or perform surgery as a mere technician. But medicine, like so many fields, develops when minds think and see anew.  When they philosophize. I am happy to have lived a life in which thinking played a significant role.

Can A Machine Think? Discussed in One Page

Descartes thought machines couldn’t think because they couldn’t speak or understand language. That is no longer true. [If you doubt this go to and converse with Alice:  This is an old program, much newer ones are available.]

An Argument that Machines Could Think – If your biological brain is replaced, piece by piece by non-biological parts, and still functions the same, then machines can think (and you would essentially be a machine.) And if mechanical parts could sustain consciousness for you, then they could do so for a robot too.

Objection – Computers Only Do What They Are Programmed To Do

Response – It is true that computers today aren’t conscious of what they do in the way that we are; but it is false that they can do only what they are programmed to do. Furthermore, what machines can do today is irrelevant to what they will be able to do tomorrow, or a million years from now. To say they can’t think is to beg the question. In fact, maybe we only execute a program. But if a machine could do everything a human could do, there would be no good reason to insist that it wasn’t conscious.

The Turing Test – The idea is that a machine passes the “turing test” if a human cannot tell whether they are talking with a person or computer. Just last year it was announced that a computer program had passed the test.(Although some doubt this claim.)

Why the Turing Test Fails – But is this test valid for determining if something is conscious? One reason to think not is that the test rests on behavioristic assumptions—mental life is demonstrated by behaviors—but behaviorism is generally discredited. A second reason has to do with the “Chinese room argument.”

Chinese Room Argument – You pass a note in Chinese thru a slot, and on the inside of the room a person follows instructions that send back answers in Chinese, even though the person inside doesn’t understand Chinese. Isn’t this analogous to a computer which receives inputs, executes a program, but doesn’t “understand” what it’s doing? Don’t computers only understand syntactical rules, but not semantics? (Philosophers tend to be very impressed with this argument, computer scientists not so much.)

Objection – What More Do You Want? – If it walks and talks like a duck, its’ probably a duck. If machines do what humans do, then we have as much evidence they are conscious as we do that other people are conscious. REPLY – But consciousness isn’t deduced exclusively from behavior, we know our own consciousness “from the inside.” If we knew how the brain gives rise to consciousness, then we could see if computer had similar features.

Summary of Philosophy of Mind

Mind-body dualism – The body is material and governed by physical law; the mind immaterial and not governed by physical law. Reality is dual, composed of both physical and mental facts. According to Descartes, persons have privileged access to their mental states, and they are infallible with respect to those states.

Objections to dualism – 1) How do non-physical things interact with physical things, inasmuch as they are completely different kinds of things? 2) The idea of a non-material substance makes no sense; 3) It seems impossible for dualism to explain how immaterial mind emerged in the first place, given that reality started completely material.

Materialistic theories of mind – There is nothing ghostly or non-physical within us;  the physical explains the mental.

1) Logical Behaviorism – Behaviorists hold that being in a mental state is the same as being in a physical state. In other words, since all we can know about another person’s state of mind is through their behavior, there is nothing else. Thus any statement about the internal or private world of individuals may be translated into a statement about publicly observable actions. For instance, if I say, “I am happy”, this may be translated into a description of my physical state—increased heart rate, smiling, etc.

Gilbert Ryle took this one step further and eliminated mental events altogether. We don’t have to explain immaterial substances or how they interact with matter because there are no immaterial substances.

Problem with behaviorism – 1) Mental states seem to exist without corresponding behaviors. 2) Not all mental states correspond to behaviors. (What behavior corresponds to listening to Mozart?) 3) Different mental states can correspond to identical behaviors.

2) Mind-brain identity theory – Brain events cause mental events. Science confirms that brain physiology causes mental events. Mental events and states are neurological. This explains: a) mental facts without positing souls; b) how mind and body are connected; c) thought without necessary reference to behavior, and d) introspection.

Problems with identity theory – If mental states are brain states, then things without brains (aliens, robots) couldn’t feel, for example, pain or joy. But couldn’t robots without brains feel pain if they were wired to feel pain? This thinking leads to another theory:

3) Functionalism – mental states (like pain) are equivalent to whatever physical system (cells, wires, chips, etc.) serves the function of creating experiences. For us, pain is neurons firing to link input with output, for aliens or robots, this might have to do with different biological or mechanical wiring. So functionalism is an advanced theoretical version of mind-brain identity to account for robots, aliens, etc.

Problem with functionalism – Wires or chips can’t be the basis of consciousness, and robots without brains wouldn’t be conscious even if they acted conscious.

Basic objections to any materialist theory of mind

Having subjective experiences is the “what it is like” to have a mind. But how does a brain state equal a taste, feel or smell? [Philosophers refer to these states as “qualia.”] The idea is that neuron firings are objective while brain states are subjective. This is the biggest problem for materialistic theories of mind.

This problem is related to another problem for materialistic theories of mind—the problem of intentionality. Intentionality is the idea that mental states are about things. But how are neurons in brains about things? We might explain this by saying that brains resemble colors or smells, but this doesn’t seem right. Brains may be about smells or colors, but colors or smells aren’t about brains. Now we could say that brain states resemble mental states, but they don’t. If we look at your brain when you see green trees we won’t see green brains! And if we think about an abstract idea like the square root of -1, there is no physical thing that could look like that. So it doesn’t seem that resemblance between brains and minds explains how brains give rise to minds.

So perhaps we shouldn’t draw any conclusions about the philosophy of mind and the mind-body problem since there is so much we don’t know about neurophysiology. Yet we are learning all the time and most neurobiologists think the brain will eventually be fully explained. For the moment though, we might take Wittgenstein’s advice:  What we cannot speak of we must pass over in silence.

(This entry relied heavily on James and Stuart Rachels’ book: Problems from Philosophy.)

Summary of the Problem of Personal Identity

A Treatise Of Human Nature by David Hume

(This article was reprinted in the online magazine of the Institute for Ethics & Emerging Technologies, April 25, 2015.)

The problem – Is a person the kind of thing that can die on earth and be alive somewhere else? To understand this consider a thought experiment. If we make a perfect copy of you—complete with your thoughts and memories—is that copy really you or just a duplicate? (If you think the copy is you, then the “waking up in heaven scenario” is not problematic; if you think it’s just a copy, then the thing that wakes up in heaven isn’t you.)

Personhood at a moment – What is it to be a person at a particular moment? The bundle theory says you are a body and the mental events in your brain. There is nothing more to you than that. The soul theory says that there is more to you than this, there is a core to you that we might call your soul, ego, or self. So the bundle theory denies what the soul theory affirms—that there is some inner core that is the real you. David Hume, the Buddhists, and others deny there is any such core.

Split brains – Modern science accords well with the bundle theory, but not the soul theory. For example, if one severs the brains’ hemispheres one seems to create different persons. This does not fit well with the idea of a unified soul, but on the bundle theory this is easy to explain—there are just two streams of consciousness. Moreover, if the bundle theory is correct—and science suggests it is—then the prospects for immortality seem bleak.

Personhood over Time – If soul theory were true personal identity over time means that you have the same soul in the past, present, and future. But on the bundle theory, it is hard to see what accounts for personal identity.

Qualitative and Numerical Identity – By identity, we might mean identity in the qualitative sense—qualities like patience, humor, honesty, etc.—or we might mean identity in the numerical sense—the same birth date, parents, etc. So if you meet your old high school friend Jim Smith at a reunion, you might find his qualities have changed. He used to be carefree and now he’s serious. But he is still Jim Smith, the guy you went to high school with who was born in a certain year to Mr. and Mrs. Smith. He is not an imposter.

Now you want to be the same person in the future (or in heaven) that you are now; you want there to be numerical identity. Otherwise, you will no longer exist. But what theory might explain this numerical identity? Here are some theories.

Body Theory – x is the same person as y because they have the same body.

Problems – 1) this rules out post-mortem existence because your body will decay; 2) the prince who changes bodies with the cobbler suggests that identity is not tied up exclusively with bodies; and 3) the story of the “ship of Theseus” parallels the human body story—you do not have the same body that you used to have.

Brain Theory – x is the same person as y because they have the same brain.

Problems – One problem with this theory is one can have a malfunctioning or electrically dead brain and still have an intact brain. Moreover, the brain’s physical structure changes over time even if the neurons are relatively stable. All of this suggests that the physical brain is not the locale of personal identity.

Memory Theory– x is the same as y because they possess the same memories. (This explains the prince and cobbler, the prince is still the prince even in the cobbler’s body, and it appears to make post-mortem existence possible.)

Problem – Our memories are limited. So if memories make us who we are—we aren’t much. Furthermore, how can memory theory account for personal identity when being “the same person as” should be transitive across time? But memories aren’t transitive across time in this way. At 60 you may remember your 30-year-old self, and at 30 you may remember your 10-year-old self, but at 60 it is hard to remember your 10-year-old self.

We might revise memory theory to deal with these objections by introducing the “memory-links theory.” In this theory, x is y because there is a chain of memories linking a person; persons have an identity based on psychological continuity. The problem here is how much psychological continuity there really is. Still the idea of psychological continuity appears to be a good candidate for what we mean by personal identity.

Moral responsibility – Another reason to accept the memory theory is that it fits well with our idea of moral responsibility. The argument is simple:

  • memories imply responsibility
  • responsibility implies identity
  • thus, memories imply identity

Problems – It seems you could remember a past action and no longer be responsible for it because you have changed. Why should I be responsible at 60 for something my 18-year-old self did? So responsibility should depend on a person being the same person qualitatively, not just on being the same numerically.

Is the memory theory trivial? – If our memories are unreliable, then they can’t be the basis for personal identity; but even if our memories are reliable, that doesn’t say much about personal identity. Here’s why. If I say: “I am the same person as I was twenty years ago because I remember being the same person,” then I am just presupposing that I am identical to my past self. But that doesn’t show that I am identical.

Conclusion – Philosophers generally agree that the soul theory explains nothing; instead, bundle theory and some form of psychological continuity best explain personal identity. In addition, accepting the soul or kernel theory of self gives us good reasons to be selfish; whereas the bundle theory may lead to more concern for others.

(This entry relies heavily on James and Stuart Rachels’ book: Problems from Philosophy.)