First, what do we mean by mind and what do we mean by computer? The human mind is complex and multifaceted. It encompasses reason, emotion, and action. We don’t say that about computers.
Let’s focus on a very simple, fundamental aspect of the mind: it has experiences. Philosophers call these experiences qualia. When we see the color red, hear a bell, or smell a flower, it is a subjective, first-person experience. Of course, there are physical processes involved but they result in a mental state. That mental state is what our conscious minds experience. This conscious state is the hard problem of consciousness. That’s our focus today.
In the world of computer science, there is a standard definition of a computer: anything that can be simulated on a Turing machine. But what is a Turing Machine?
It is an abstract machine. It is not a device that physically exists or even could physically exist. We imagine its existence in a purely mathematical realm. The machine operates on simple rules. Nevertheless, if the machine is appropriately configured, it can compute anything that any computer can, regardless of the computer’s sophistication.
So, by the standard definitions of computer science, a computer is something that can be simulated on this abstract mathematical device. But an abstract mathematical device cannot experience qualia or consciousness. If they could, we would expect mathematical formulas like the quadratic formula or the area of a sphere to experience consciousness. But that seems absurd, so we must conclude that a computer cannot exhibit consciousness. Put another way, consciousness is not a form of computation.
However, this logic applies to abstract computation as a mathematical model. It is possible to argue that any physical computation device would generate consciousness as some sort of side effect. Such an idea postulates laws of nature that generate consciousness under particular conditions. It is difficult to provide evidence for or against this proposition. But even if it is true, consciousness is not computation but something else, generated coincidentally with computation in the physical realm.
It should be noted that computers are actually very limited. All they can do is transform inputs into outputs. While any computing system can perform any computation (assuming sufficient time and memory), computation alone does not enable the system to act. To do anything, a computer must interact with non-computer devices in its environment—typically, screens, keyboards, mice, printers, speakers, etc.
Confusion sometimes arises because, in everyday life, we tend to think of all these devices together as “the computer.” But only the computation function is really “the computer.” To see this more clearly, consider the robot. A robot is not just a computer; it is a computer attached to various sensors and actuators so that it can do things. Universally, computers are attached to other devices in order to do anything more than compute.
The conscious mind is not computation. However, this does not mean that computation is not involved with consciousness. Rather, the conscious mind is better understood as something that interacts with the computer than the computer itself. In particular, our conscious minds appear to be observing the outputs of our physical brains, acting as computers. What we experience as qualia are thus those inputs, manifested in our minds.
If our minds take input from our brain-computers, do they also provide output? Certainly, we feel as though our minds control our brains and actions. But perhaps this an illusion. It can be argued that our minds are deluded into believing that they control the brain but are actually simply along for the ride. However, we know by direct experience that we have conscious minds experiencing qualia. We also know that our brains engage in speech and writing about consciousness and qualia. It seems a highly implausible coincidence that our brains would talk about consciousness without receiving some sort of input from our consciousness. As such, they must be under some form of control by the conscious mind of the brain.
Furthermore, I would suggest that the idea that consciousness is separate from the brain “computer” makes sense of our own experience of mind. We experience a limited degree of understanding and control over our own mind. We have a subconsciousness of which we are not fully aware. We are unaware of the details of our own thought processes. Often we have thoughts we do not want. It is as though we have some control over the inputs into our conscious mind, but it is limited. Some research suggests that we have free won’t rather than free will. That is, our conscious minds may not be able to freely choose our actions but they can veto those actions.
However, if the conscious mind is not generated by computation, what is it generated by? Most crucially, is the conscious mind generated by a physical system? This depends on what exactly we mean by “physical.” If consciousness were shown to be caused by something non-physical, the domain of physics would simply be expanded to include the new domain. As such, consciousness is not explicable by physics as we understand it today but it is impossible to show that no physics would ever explain it. The question is simply ill-formed unless we stipulate a specific definition of “physical.”
In any event, consciousness is not computation. There is simply no way to generate consciousness out of strictly computational tools. Instead, consciousness is something which interacts with computation. This is why we experience minds over which have partial but not complete control and knowledge. As for the causes of consciousness itself, we can know little except that they are something quite different from the laws of nature we have so far uncovered.
Also by Winston Ewert: Remember the Luddites! The Luddites became famous for breaking machinery during the Industrial Revolution. Were they entirely wrong? It’s not as simple as some think.
Will the Free Market Help or Hurt Us in an AI-Empowered World? We may need new institutions, such as insurance against job obsolescence
Also: We went back to visit Gödel, Escher, and Bach… Forty years after publication, how has a big explain-the-mind book withstood the test of time?