What’s it Like to Be a Bat? Contemplating the Mind-Body Problem

October 1, 2011

(Note: This is my first post in a series about the philosophy of cognitive science(s))

Today’s story begins with a well-known 16th-century French mathematician, scientist, and philosopher by the name of Descartes. Many will know Descartes for his contributions to mathematics (fun fact: He may be the reason that ‘x’ is most commonly used to express an unknown, such as a variable in an algebraic equation. For a longer discussion, see this).

Descartes also had a novel and extremely important worldview – he was one of the founders of the philosophy called “rationalism” – one which seeks absolute truths from the inside via the “pure light of reason.” Unfortunately, Descartes used the axiom “I think, therefore I am” to derive the existence of God – a dubious proof at best, one that undoubtedly calls into question Descartes’ own willingness to depart from a preexisting worldview.

But all of that is secondary. What Descartes is relevant for in the current discussion is for his theory of Cartesian dualism. Descartes believed that mind and body were dualistic, or two fundamentally separate substances. This view, popularly adapted into “soulism,” is still held by the majority of the world’s population.

Interestingly enough, even though Cartesian dualism is considered naive by today’s cognitive scientists, his work indicated that he was surprisingly willing to push the limits of a mechanistic world-view, even believing that nonhuman animals, or “brutes” as he called them, were entirely robotic. Humans were separate because of capacity for formidably complex mental feats such as natural language, and because of creative responses to novel situations. Acting as a historian, I postulate that Descartes, for the skeptic and rationalist that he was, was unable to completely divorce himself from a Catholic scientific worldview – evidence for this being his curious and convoluted arguments for the existence of God and his placement of humans in a fundamentally different category from other animals. Of course, evolution hadn’t been discovered yet so he’s not too much to blame.

The concept of Cartesian dualism, now rejected by the mainstream of philosophers, evolved into the “mind-body problem.”  To save a lot of explanation, the mind-body problem has essentially two parts:

1) Are things we consider “mental states” entirely physical?
2) If so, how can we explain such phenomena as consciousness?

To elaborate on question 1, we have to consider the difference between dualism and physicalism. Dualism is Descartes’ worldview, which holds that mental states are immaterial, whereas physicalism holds that they are entirely explained away by the particular architecture of human brains and “minds” in general. Dualism is largely debunked by the problem of causation – Burning one’s hand one a hot stove causes a mental reaction, the feeling of pain. The mental desire of hunger causes us to go and eat chips. How do these things affect each other, or how are they causally linked, if mental and physical states are distinct? To answer that we turn to physicalism.

Physicalism is, simply put, the view that all “things” in the universe are physical, so it rejects the possibility of supernatural entities or souls. So physicalism invokes something called the “monist view” of the mind-body problem – that mental states are causally linked to physical  states for the reason that they are physical states themselves. Simple enough. Within physicalism, there are various degrees of strength too. The strongest view is an actual empirical hypothesis waiting to be proven, the “type-identity theory,” which states that mental states and properties are identical to physical states and properties. This is particularly bold because it seems to suggest that every mind which contains the idea that “grass is green” would have some identical structure. I think that this inference isn’t completely accurate – different minds such as that of a cricket compared to that of a snake could contain the representation of grass analogously or isomorphically (Douglas Hofstadter’s term) but wouldn’t necessarily have to be identical to for the type-identity theory to hold.

There are also weaker forms of physicalism, especially property dualism or nonreductive physicalism, which says that even though physicalism is correct, it is not fully reductionist – i. e. low-level properties of physical objects such as magnitude, velocity, chemical composition, etc are not always sufficient to explain higher-level phenomena such as psychological states. This is closely related to emergentism, which holds that even though high levels of organization in a complex system such as the brain are dependent on low-level activity, they cannot be explained through the lower-level activity. Some thinkers, myself included, believe that the theory of emergence sweeps the problem under the rug, and isn’t fundamentally distinct from believing in dualism anyway, since it relies on “mystery” and “the unknown.”

So that largely sums up the answer to the first part of the mind-body problem, ie. whether mental states are physical or not. The second part is a lot trickier though. We arrive at something that Thomas Nagel terms “the knowledge problem” – even if we knew all the physical “facts” about the phenomenon of pain, for example, we wouldn’t know what pain feels like, extrapolating from those facts about pain. In his famous paper “What is it like to be a bat?” Nagel delivers a critique against reductionist physicalists who reduce the problem of understanding consciousness to “low-level neuronal activity” without being more specific. According to Nagel, “consciousness is what makes the mind-body problem really intractable.” Can we imagine different intelligent cognitive architectures? By some stretch of the imagination, we may be able to imagine what it’s like to be a bat. But now we only know what it’s like for a human to be a bat…what about what it’s like for a bat to be a bat? Does being a bat feel like anything? Is that an absurd question, like asking what it feels like to be a water bottle? Or is it somewhere in between?

I guess I’ve probably provided more answers than questions. Consciousness will be dealt with in more detail later. But in the meantime, we swing around full circle to Descartes, who, as you might remember, believed animals were essentially robots. We all observe apparently intelligent behavior in “lower creatures,” even insects, but is it really intelligent or is it just robotic, as Descartes would say? Here’s an excerpt on the “sphex wasp” provided by Douglas Hofstadter in Godel, Escher, Bach:

When the time comes for egg laying, the wasp Sphex builds a burrow for the purpose and seeks out a cricket which she stings in such a way as to paralyze but not kill it. She drags the cricket into the burrow, lays her eggs alongside, closes the burrow, then flies away, never to return. In due course, the eggs hatch and the wasp grubs feed off the paralyzed cricket, which has not decayed, having been kept in the wasp equivalent of a deepfreeze. To the human mind, such an elaborately organized and seemingly purposeful routine conveys a convincing flavor of logic and thoughtfulness — until more details are examined. For example, the wasp’s routine is to bring the paralyzed cricket to the burrow, leave it on the threshold, go inside to see that all is well, emerge, and then drag the cricket in. If the cricket is moved a few inches away while the wasp is inside making her preliminary inspection, the wasp, on emerging from the burrow, will bring the cricket back to the threshold, but not inside, and will then repeat the preparatory procedure of entering the burrow to see that everything is all right. If again the cricket is removed a few inches while the wasp is inside, once again she will move the cricket up to the threshold and reenter the burrow for a final check. The wasp never thinks of pulling the cricket straight in. On one occasion this procedure was repeated forty times, with the same result. [from Dean Wooldridge’s Mechanical Man: The Physical Basis of Intelligent Life]

Well that’s all I have to say on the mind-body problem for now. Stay tuned for more!

Further Reading:

What Is It Like to Be a Bat? – Thomas Nagel

(Note: All information is from MITECS and personal reflection (this is philosophy, after all), unless otherwise stated)

The Chinese Room – introduction

August 16, 2011

What’s the Chinese Room Argument?

I’ve blogged before about the Turing Test several times; Alan Turing held the position that if a program was indistinguishable from a human mind in all manners of interaction, then it could be considered “conscious,” whatever that means. This position is formally known as “Strong AI” – in other words, hardware is inessential to the working of a mind – cognitive states can equally well be implemented on computers as on human brains.

For many, this is a troubling stance. It is difficult to argue that computers will never come to pass the Turing test, but there is a position which states that computers can only simulate thought and not demonstrate actual understanding – “weak AI.” Weak AI draws a line between simulating thought and actual thought; thought simulation is the manipulation of abstract symbols to produce output indistinguishable from the of a human, whereas actual thought consists of “states,” connects syntax with semantics, words such as  “tree” associated with sensory experience and memory, and involves understanding.

John R. Searle formulated an impressive argument for weak AI known as the “Chinese Room argument.” Here, we are taken to assume that the Turing Test exchange is in Chinese. Instead of a computer running the program, we have an English speaker who does not understand Chinese. Their job is to receive input in the form of Chinese characters. Then they follow would rules in a book (the program) in manipulating symbols in other books (the databases) in order to produce Chinese characters in output. The man doing the manipulations does not understand Chinese, and the program does not allow him to; hence the program does not “understand Chinese.” Strong AI is thus false, because programs cannot create understanding.

In the essay, Minds, Brains, and Programs, in which Searle produces this thought experiment, he presents and responds to a number of counterarguments. A few of them are listed here  –

  1. The Systems argument – understanding is an epiphenomenon, and perhaps although the man himself does not understand Chinese, the entire system does in fact possess an understanding. Searle deftly strikes this down; if the man were to memorize the program and the database, he would have internalized the entire system, yet he would still not understand Chinese.
  2. The Robot argument – If we created a robot with the program running as its brain, which was able to take in input via cameras and sensors and act accordingly, then surely it would show understanding of the world. Searle refutes this argument as well, emphasizing the lack of qualitative difference between the original program and this robot.
  3. “Many Mansions” argument – “Your whole argument presupposes that AI is only about analog and digital computers. But that happens to be the present state of technology.” Searle pokes fun of his opponents here, noting correctly that the “Strong AI” stance is supposed to be hardware-independent, such that any computational device should support intelligence if programmed correctly.

And so by introducing straw men and striking them down easily, Searle apparently solidifies his position. Or does he? Daniel Dennett provides a far more convincing counter-argument, which I’ll introduce in my next post.

“Why do we have to know this?”

July 26, 2011

I’ve been in enough science classes from elementary through high school to know that there’s almost always that one kid who doesn’t really seem to belong in the class but’s there anyway for some inexplicable reason, if only to interrupt the teacher’s enthralling PowerPoint presentation on double fertilization in angiosperms with that question. THAT QUESTION. The question that renders self-confident and well-informed science teachers mumbling and sheepish. Sometimes they ignore it, and sometimes they offer something like, “It’s important even if you don’t like it that much.”

So even though a lot of people would dismiss the occasional “Why do we have to know this?” as absurd and immature, I think that an even higher portion of the population would occasionally, when memorizing the multiple steps of fungus reproduction or glycolysis in biology, poring over solubility charts in chemistry (exceptions included!), or wrestling with free-body diagrams in order to set up the correct equations in physics, wonder why they’re doing this and not something much more directly linked to future success, like, say, liberal arts.

Read the rest of this entry »

Computer Science and Philosophy: Procedural Epistemology

July 23, 2011

Today Amazon delivered me my first ever textbook for college (!) and the latest edition to the “computer science canon” that I’m currently collecting – Abelson, Sussman, and Sussman’s classic Structure and Interpretation of Computer Programs.

…I think it’s quite an exciting day. Naturally, I began to read the first few pages and came across a fascinating paragraph: Read the rest of this entry »

Descartes’ zero-axiom system

May 30, 2011

Descartes’ zero-axiom system

I first properly encountered Descartes in European History class, where he was introduced as the great skeptic who had rejected everything he believed, leaving only the essential, irrefutable, true-in-all-conceivable-universes “I think, therefore I am” – cogito ergo sum. Magnificent.

I had always meant to read some Cartesian philosophy, but I guess it slipped my mind. Except that this system of assuming nothing kept coming up. Douglas Adams references it in The Hitchhiker’s Guide to the Galaxy with Deep Thought, the super-computer which had been fed “I think therefore I am” and had deduced the existence of rice pudding and income tax in a blink of an eye.

Descartes’ fear of an “infinitely powerful demon” which sought to deceive mankind and which could only be defeated or circumvented by the “natural light of reason” is also referenced frequently in other writing, although less than respectfully.  Read the rest of this entry »