On understanding, intuition, and Searle’s Chinese Room

You’ve just bought the latest in personal-assistant robots. You say to it: “Please put the dirty dishes in the dishwasher, then hoover the lounge, and then take the dog for a walk”. The robot is equipped with a microphone, speech-recognition software, and extensive programming on how to do tasks. It responds to your speech by doing exactly as requested, and ends up taking hold of the dog’s leash and setting off out of the house. All of this is well within current technological capability.

Did the robot understand the instructions?

Roughly half of people asked would answer, “yes of course it did, you’ve just said it did”, and be somewhat baffled by the question. The other half would reply along the lines of, “no, of course the robot did not understand, it was merely following a course determined by its programming and its sensory inputs; its microprocessor was simply shuffling symbols around, but it did not understand”.

Such people — let’s call them Searlites — have an intuition that “understanding” requires more than the “mere” mechanical processing of information, and thus they declare that a mere computer can’t actually “understand”.

The rest of us can’t see the problem. We — let’s call ourselves Dennettites — ask what is missing from the above robot such that it falls short of “understanding”. We point out that our own brains are doing the same sort of information processing in a material network, just to a vastly greater degree. We might suspect the Searlites of hankering after a “soul” or some other form of dualism.

The Searlites reject the charge, and maintain that they fully accept the principles of physical materialism, but then state that it is blatantly obvious that when the brain “understands” something it is doing more than “merely” shuffling symbols around in a computational device. Though they cannot say what. They thus regard the issue as a huge philosophical puzzle that needs to be resolved, and which may even point to the incompleteness of the materialist world-view.

What does “existence” mean?

During a recent online discussion I discovered, somewhat to my surprise, that there is no general agreement on what the word “exist” means. Everyone has an intuitive understanding of it but when it comes to an explicit definition of the word there is no consensus, and indeed philosophers have written a vast literature on the topic of ontology, or what exists.

Dictionaries don’t really help; for example Oxford Dictionaries gives a nicely circular set of definitions:

Exist: 1. have objective reality or being
Reality: 1. the state of things as they actually exist
Being: 1. existence.

Of course physicists have a perfectly good operational definition: something exists if it is capable of making a detector go ping. Try arguing that, however, and you’re immediately accused of materialism, physicalism, scientism, being blind to possibilities beyond a very narrow world-view, and a host of similar sins (I plead guilty to at least the first three).

Nagel’s bat doesn’t demonstrate incompleteness in materialist science

Philosopher Thomas Nagel is well known for rejecting the idea that science can explain all aspects of the human condition, a view expounded in his influential paper “What is it like to be a bat?”, and recently in a book trying to overturn materialist Darwinism as an inadequate explanation of life (Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature is Almost Certainly False). Nagel sums up his argument in the New York Times:

… it seems natural to think that the physical sciences can in principle provide the basis for an explanation of the mental aspects of reality as well …

However, I believe this possibility is ruled out … The physical sciences can describe organisms like ourselves … but they cannot describe the subjective experiences of such organisms or how the world appears to their different particular points of view. There can be a purely physical description of the neurophysiological processes that give rise to an experience, and also of the physical behavior that is typically associated with it, but such a description, however complete, will leave out the subjective essence of the experience — how it is from the point of view of its subject — without which it would not be a conscious experience at all.

So the physical sciences, in spite of their extraordinary success in their own domain, necessarily leave an important aspect of nature unexplained.

Let’s clarify what the materialist account of a “subjective experience” is. The brain is a network of neurons, connected to each other by dendrites and synapses. Electrical and chemical signals flow through the network in complex patterns. Those patterns are our thoughts. Our thinking and deliberation and decision-making are patterns of electrical firing flitting around our neural-network brain. A particular thought, a particular sensation, or a particular subjective experience, are all particular patterns of electrical firing.

Nagel is asserting that we can understand every physical aspect of this phenomenon, having a complete knowledge of the network and the electrical signals, and yet not understand “the subjective essence of the experience”, and thus not understand what it is like to be a bat. From there he rejects materialism as incomplete, and goes on to reject any materialist account of life.

My reply is, yes, Nagel is right, indeed we cannot always appreciate the subjective essence of an experience, but that is not a limitation of materialism and not a limitation of materialist science.