Philosophers have long struggled with the question of whether consciousness is reducible to physical properties or is irreducibly mental. With few exceptions, recent day philosophers have argued that consciousness is physical. Some think consciousness just is a property of the brain. Others think that mental properties and physical properties are distinct but that mental properties depend on physical properties of the brain. The majority of these views have the implications that there will be a time at which physics can fully explain consciousness (there is no explanatory gap) and that there is only one fundamental type of properties: namely, the most basic physical properties (there is no ontological gap).
New evidence published in the science journal Nature's Scientific Reports suggests a new way in which mental properties could be reducible to physical properties but without the implication that there is only one type of fundamental properties. The researchers, led by Dmitri Krioukov from the San Diego Supercomputer Center at UC San Diego, discovered that the growth and organization of the universe appear to be equivalent to the structure and growth of complex networks, such as the brain, the conscious mind, the Internet and social networks. They believe this equivalence indicates that laws very similar to those that govern the universe govern other complex systems.
Krioukov and colleagues used complex supercomputer simulations of the universe to show that the causal network that represents spacetime is a graph that is notably similar to technological, social and biological networks, suggesting that there is a single, fundamental law that governs the growth and structure of networks. The researchers do not yet know the nature of this chief law.
Creating simulations that represent the universe is no small feet. The researchers had to downscale the universe to a size that could be processed by a computer. They also had to prove that the essential properties of spacetime do not depend on the size or the age of the network in question. If a fundamental law is indeed governing all networks, it would have different limiting regimes, which would include the laws of gravity. For each special network there would be a limiting regime describing its dynamics.
If the team is right, what could this tell us about consciousnesst? We already know from physics that there are four elementary forces and 12 elementary “matter” particles. The four elementary forces are gravity, electromagnetism and the weak and strong nuclear force. The 12 elementary particles include six quarks and six leptons. The quarks are components of neutrons and protons. The leptons include the electron, two siblings of the electron and three neutrinos. Forces are made up of elementary “force” particles, which all exhibit wave-particle duality. For example, light is made up of photons. The strong and weak nuclear forces are made up of gluons and W and Z bosons. No one knows exactly what constitutes gravity.
The four elementary forces and the 12 elementary particles constitute physical matter. They are all governed by some limiting physical regimen. But this regimen is an instance of a more fundamental law of nature that has limiting regimens that govern other networks, say the researchers. It is not unlikely then that other networks, including the conscious mind, consist of elementary particles or elementary forces (or both) that would be the elements subjected to the limiting regimens.
If one fundamental law governs all dynamic networks, we could say that the conscious mind, or consciousness more generally, is physical in the explanatory sense. But mental properties would not be reducible to the elementary particles or forces of physics. Though governed by the same fundamental law as the elementary items of physics, consciousness would be grounded in its own type of elementary forces or particles. So, the newfound equivalence among complex systems may be taken to suggest that a type of dualism about the mind would be true in terms of what exists but not in terms of what we can come to know by studying the laws of physics. If one fundamental law governs all complex system, we should eventually be able to offer a kind of physical explanation of how consciousness arises from more elementary stuff.