Is everyone in the world somewhat conscious?
Panpsychism is the belief that consciousness can be found throughout the world – not only in humans and animals, but also in trees, plants, and bacteria. Panpsychists say that some aspects of the mind are present even in elementary particles. The idea of widespread consciousness is appealing to many for intellectual and, perhaps, emotional factors as well. But can it be empirically tested? Surprisingly, it might be possible. That’s because one of the most famous theories in the science of consciousness, integrated information theory (IIT), shares many-though not all-forms of panpsychism.
As the American philosopher Thomas Nagel Arguably, someone knows if there is a “something like this” thing in the state it is in. A human brain in the state of awakening feels like something specific.
The IIT defines a unique number, a combined information in a system, marked with the Greek letter φ (pronounced phi). If φ is zero, the system feels nothing; in fact, the system does not exist as a whole, because it is completely renewable in its component parts. The more φ, the more familiar with a system, and the more indestructible it is. Due to an accurate and complete description of a system, IIT predicts the quantity and quality of its experience (if any). The IIT predicted that due to the structure of the human brain, humans have high values of φ, while animals have small (but positive) values and classical digital computers have almost none.
The value of φ in a person is not constant. This increases the period in early childhood with self-improvement and may reduce the onset of dementia and other mental disabilities. Φ will fluctuate while sleeping, becoming more dreamy and slightly deeper, dreamless state.
IIT begins by identifying the five real and essential characteristics of any and every imaginable conscious experience. For example, experiences are certain (not included). This means that an experience is not less than this (only experiencing the sensation of the color blue but not the moving ocean that brings to mind the color), nor is it more than this (i.e., experiencing the ocean while knowing also in the canopy of the trees behind a person’s back). In a second step, IIT acquired five related physical properties that any system – brain, computer, pine, sand dune – must display to feel like something. An IIT “mechanism” is anything that plays a significant role in a system; it could be a logical gateway to a computer or a neuron in the brain. The IIT states that consciousness only emerges in mechanistic systems that have a specific structure. To make it a little easier, that structure needs to be as closely spaced as possible – not accurately described by dividing it into the components it comprises. It must also have cause-and-effect power of its own, which is to say that the present state of a given mechanism must prevent future states not only of that specific mechanism, but the system as a whole.
Given an accurate physical description of a system, the theory provides a way to calculate the φ of that system. The technical details of how it was done complex, but what comes out is that one can, in principle, target to measure φ in a system as long as there is a similarly accurate description of it. (We can calculate φ in computers because, in doing so, we understand it correctly. Calculating φ in a human brain is another estimate.)
Systems can be tested at different levels-one can measure φ on a scale of sugar in my brain, or my brain as a whole, or me and you together. Similarly, one can measure φ on a silicon atom, on a particular circuit on a microchip, or on an assembly of microchips that make up a supercomputer. Consciousness, in theory, exists for systems where φ has the most. It is available for all such systems, and only for those systems.
The φ in my brain is much more than the amounts of any of its parts, even if one comes out to divide it. That’s why I have a conscience. But my φ and you are a little more alike than my φ or your φ, so we are not “together” consciously. However, however, a future technology could create a thick center of communication between my brain and your brain, so that making the brain brain create a mind, distributed in four hemispheres of the world.
In contrast, the φ of a supercomputer is smaller than the φ of any of the circuits that make it, so a supercomputer – no matter how big and powerful – is unconscious. The theory predicts that even if some deep learning system passes the Turing test, it could become a so-called “zombie” —emotivation of consciousness, but not actually consciousness.
Like panpsychism, therefore, the IIT considers consciousness a natural, fundamental property of the marked and likely reality of the tree of life, since any system with a non-zero value of integrated information feels like something. This does not mean that a bee will feel obese or make plans for the weekend. But a bee can feel a measure of happiness when it returns the pollen -filled sun to its home. If a bee dies, it will stop experiencing anything. Also, because of the sheer complexity even in a single cell, with millions of proteins attached, it can feel a little bit like something.
Debating the nature of consciousness may at first seem like an academic exercise, but it has real and important consequences. Most obviously, it matters how we think of people in plant states. Such patients may moan or otherwise move unchecked but are unable to respond to signal commands in an objective manner by moving their eyes or nodding. Is there a consciousness that their mind, trapped in the damaged body, is seen but unable to respond? Or are they unconscious?
Evaluating such patients for the presence of consciousness is difficult. The proponents of IIT have developed a method that can be tested for the consciousness of an unresponsive person. First they set up a network of EEG electrodes that could measure the electrical activity of the brain. After this they activate the brain with a gentle magnetic pulse, and record the sounds of that pulse. They can then calculate a mathematical measure of the complexity of those sounds, called a perturbational complexity index (PCI).
In healthy, conscious individuals — or people with brain damage but clearly conscious-PCI is always above a certain standard. On the other hand, 100% of the time, when healthy people are asleep, their PCI is below that standard (0.31). It makes sense to take PCI as a proxy for the presence of a conscious mind. If the PCI of a person who is in the constant plant state is always measured to be below this threshold, we are confident that it is as if this person has no hidden consciousness.
This approach is being investigated in several clinical centers throughout the US and Europe. Other experiments seek to confirm predictions made by the IIT about the location and timing of sensory consciousness footprints in the brains of humans, non-human primates, and mice.
Unlike panpsychism, IIT’s shocking claims can be empirically tested. If they hold, science may have found a way to break a will that confuses philosophers until there is a philosophy.
Christof Koch is the lead scientist in the MindScope program at the Allen Institute for Brain Science in Seattle.