At some point in time we’ve all been curious about what it means to be alive. Why are we conscious? And how does our subjective experience come about in the first place? The computer you’re reading this on doesn’t have experiences but you do. Why is that? Believe it or not, we’re at a point in history where science can give us a rather satisfying explanation of these matters. In this post, we explore precisely how.
The findings of cognitive science have taught us that the brain, for all intents and purposes, is simply a biological information processing system. An information processing system is any physical system that has the ability to perform computations. We typically call such things “computers.” One of the simplest and earliest computers we know of is what’s called a “turing machine.” The computers we use nowadays are evolved forms of the purely mechanistic turing machine, and this is important because it demonstrates how information processing systems are simply physical systems exhibiting a particular type of activity. This means that, despite the relative complexity of each, our laptops and our brains are two forms of the same one, physically realizable, thing: information processing.
The difference between the information processing which occurs in our brains and that which occurs in our laptops is that the former evolved through billions of years of natural selection and developed the capacity to simulate conscious phenomenal experience. Throughout evolutionary history, organisms have needed to process information about themselves and their immediate surroundings. The ones who could process information with the greatest efficiency were the ones that were able to survive and pass on their genes. And just as evolution has shown us that wings are the most efficient way to travel through air, it now seems to be telling us that the most efficient way to process biologically relevant information is through phenomenal consciousness. All that may sound a bit confusing, so why don’t we take a moment to go back to the basics. The best place to start is with the story of evolution:
It all began…
To bring the matter home, let us consider the difference between our own conscious and unconscious states. For instance, what was it like to wake up this morning? If we awoke from a dreamless sleep, we might say that we were simply unconscious one moment and then conscious the next. Yet the brain is active when we are asleep and when we are awake. So the difference between these two states must correspond to the particular type of processing that the brain exhibits in them. We could say that when we are awake the brain exhibits conscious information processing, while when we are asleep it exhibits unconscious information processing. This is no doubt a simplification, but the distinction is useful for our present discussion.
Cognitive scientists have identified three criteria which account for the difference between conscious and unconscious information processing. And if we were to build a computer that was powerful enough to satisfy these requirements, it could support a conscious being just as our own bodies do (for the sake of simplicity, the potentially necessary features of quantum computing and electromagnetic phase synchrony are ignored here). The three criteria for conscious processing are: global availability, presence, and transparency.
Global Availability – To aid in their survival, many biological information processing systems generate an internal model of reality. Phenomenally conscious information is precisely that subset of currently active information in the system of which it is true that it is globally available for many different processing capacities at the same time. In this way, the different functionally independent subsystems of the organism (e.g. proprioception and vision) can be coordinated and optimized into the meta-system of its whole being.
Presence – A second core aspect of conscious processing is what could be described as the generation of an island of presence in the continuos flow of physical time. Phenomenal content is invariably content of “the now,” because it is necessarily associated with a simulation of temporal internality. There is an overarching temporal context governing the organism’s phenomenal experience, and this context generates the experience of presence.
Transparency – Phenomenal transparency means that something particular is not accessible to subjective experience, namely the simulated nature of the content of experience itself. What makes the simulation of phenomenal experience transparent is the attentional unavailability of earlier stages of processing for introspection. The instruments of simulation themselves are not simulated a such, and thus the system instantiating the experience is entangled in a naive realism. It believes that what it witness is real, that the outside world and its own physical self are truly existent, and not just the result of its own processes.
Using everything discussed so far, we may now better understand the relation between biological and manmade information processors and the issue of how our conscious human experience arises in the first place. To this end, let us consider one last analogy between the brain and the computer. This analogy is not perfect but it may still bring a great deal of clarity to the discussion: Just as a computer can run software to simulate a virtual reality, the brain runs evolutionary “software” to simulate a virtual reality for the organism as a whole. These simulations correspond to the conscious experience of the organism in which the brain resides, and they exist because they are the most adaptive way to process biologically relevant information. Organisms without such reality simulations would have been outcompeted into extinction. Computers did not evolve under the same pressures and therefore have relatively limited abilities. Yet brains and computers still share a few similar features:
From the perspective of cognitive science, everything we experience as real is simply a simulation run on the biological computer that is our nervous system. The functions of our nervous system are centralized in our brain. The difference between a reality that’s simulated by a desktop computer and one that’s simulated by a brain, is simply that the brain’s simulations are more compelling. For despite the relative complexity of each, computers and brains are two different forms of the same one thing: information processing systems. But unlike the computer, our brain’s evolved through the forces of evolution and somehow developed the ability to simulate conscious phenomenal experience.