In part 1a, we covered what the mind/body problem is, and the thought experiment Descartes used to arrive at the famous conjecture “cogito ergo sum” — I think, therefore I am. He also arrived at the notion that we are both material things, and idealist things, together – entities that have a physical nature (materialism), and entities that have a mental nature (idealism), at the same time. This is called dualism.
And before I go further, I’d like to take a moment to discuss idealism in particular. In modern Western societies, where schooling focuses heavily on a materialist viewpoint (especially in the sciences), the notion of a universe constructed of ideas, thoughts, and perceptions alone might seem a bit daft.
“For my thoughts are not your thoughts”
In simplest terms, ontological* idealism is the notion that nothing exists outside of the mind’s eye; reality is mentally constructed and consists of perceptions and observations. When something is no longer observable, such as an item in the next room, then it no longer exists. The concept extends from a skepticism that anything beyond the mind can truly be “knowable,” and was often used to justify the concept of an omnipresent God.
To help explain idealism, you may have heard the old question, “If a tree fell in the forest, but no one was there to hear it, would it have made a sound?” According to old Church doctrine, yes it would have, because God is there even if you aren’t, and He perceives all things at all times, so the tree makes a sound because God is there to hear it.
Another way to describe the idealism of the Church is to use the famous limerick, “God in the Quad:”
There was a young man who said “God— Monsignor Ronald Knox
Must find it exceedingly odd
To think that the tree
Should continue to be
When there’s no one about in the quad.”
“Dear Sir: Your astonishment’s odd;
I am always about in the quad.
And that’s why the tree
Will continue to be
Since observed by, Yours faithfully, God.”
To continue: it’s recognized today that Descartes, for all his genius, made a fundamental categorical error: he needed to (logically) prove the existence of a non-deceiving God in order to arrive at a place where he could be certain he wasn’t being deceived at every turn by his own mind. In performing his “hyperbolic doubt” thought experiment, he defined “to know” as “to know without a doubt,” which would be a somewhat different interpretation than we would use today.
This is what’s known as Descartes’ “category-mistake.” Descartes knew (with certainty!) that 5+3=8, and to hold otherwise would naturally place one in contradiction; his error was in applying this logic to everything, not just mathematics. Today we would differentiate between math, which has a certainty attached to it, and factual (empirical) claims which are always subject to modification upon receiving new data.
“You can go with this, or you can go with that”
Descartes wrote, “As to the body, however, I have no doubts about it, but thought I knew its nature distinctly. […] a body I understand has whatever has a determinable shape and a definable location and can occupy a space […] can be perceived by touch, sight, hearing, taste or smell [… however,] the power of self-movement, like the power of sensation or of thought, was quite foreign to the nature of a body; indeed, it was a source of wonder to me that certain bodies were found to contain faculties of this kind.” In other words, despite being able to prove (logically) that he did indeed exist as both a body and a mind, he still couldn’t understand how material objects (like human bodies) could operate via mental activity.
How does the mind make a connection to the physical world, thought Descartes? The mind is not created by the imagination, and it cannot be envisioned by it. We can imagine chairs and cars and carrots because they are external to us. We cannot imagine our minds, as entities; we can only imagine situations and circumstances in which we find ourselves, such as in dreams or hypothetical situations. A mind is casually regarded as a “thing,” as real as the seat I’m sitting on, yet it has none of the qualities we expect from anything else in reality.
Not only is this problem present when considering one’s own mind, but how can we ever claim to “know” that the minds of others even exist – that we’re not making up all this interaction in our own heads? How do we prevent ourselves from slipping into solipsism? Philosophers and thinkers of all stripes have been wrestling with this dilemma since, and the dawning of the computer age — with the possibility of artificial intelligence — has only complicated the issue. Bad enough we can’t quite grok the bridge between mind and brain; now we’re going to cope with minds that don’t have (human) brains to begin with?
The Ghost in the Machine
Before we consider thinking machines, and whether they have cognition of any sort at all, let’s stop first to consider Gilbert Ryle, one of the most influential philosophers of the 20th century. Ryle referred to the “official doctrine” of Descartes’ dualist notions as the “ghost in the machine,” referencing the category-mistake on the part of Descartes’ reasoning.
Ryle defined the Cartesian category-mistake thusly: Minds are not clocks; they are immaterial and must operate on immaterial processes. “It is perfectly proper to say, in one logical tone of voice, that there exist minds and to say, in another logical tone of voice, that there exist bodies. But these expressions do not indicate two different species of existence, for ‘existence’ is not a generic word like ‘coloured’ or ‘sexed.’ They indicate two different senses of [the word] ‘exist,’ somewhat as ‘rising’ has different senses in ‘the tide is rising,’ ‘hope is rising’ […] [similarly] that there exist minds and bodies.”
In other words, Ryle surmised that minds cannot be physical things, but also that we do not exist in a dualist universe — instead, minds may exist in a different way than the rest of the (physical) universe does.
For all this energy expended in assessing the category-mistakes of Descartes, we’re left wondering if the mind-body problem had actually been dissolved in doing so. Many still ascribe to viewpoints based on idealism, others with viewpoints based on materialism, both attempting to include both mind and body in the set of “things” encompassed by either philosophy. Yet by defining minds as something other than what the rest of the universe is composed of, existing differently than everything else, Ryle may have eliminated the problem altogether.
Perhaps the mind exists differently than everything else. The mind may be a construct of consciousness, a tool of cognition or perception, an illusion or a delusion of self-perception, and thus is not “made of” anything at all.
Next, we’ll consider the theory of functionalism, the claim that it doesn’t matter what the brain is actually made of, but only whether it’s capable of performing complex computations (its mental ability, or state). This attempt to resolve the mind/body problem is related to cognitive science, a mixture of psychology, mathematics, philosophy, linguistics and the computer sciences. Enter Jerry Fodor, a staunch proponent of functionalism, in part 2 of our examination of the mind/body problem.
*It should be noted that this is a very simplified recounting of philosophical ontological idealism. See Britannica’s article on Idealism for further edification.