Science and the Search for the Soul (2): Not Everything That Exists is Purely Physical
The world is more than just an assembly of physical particles. Pragmatical arguments force us to give up the idea that, ultimately, everything must be accounted for by physics. This allows a pluralistic and complementary view for all scientific disciplines and helps us to avoid a philosophical stance that takes the world to be much more simple than we observe and experience it. Simplicity can be a virtue, but with regard to the sheer complexity of our world it can be a vice.
In part one of this series, I presented two philosophical ideas: First, that people’s minds are just an assembly of nerve cells and their behavior, expressed in Francis Crick’s Astonishing Hypothesis; second, that everything that we see in our world is just made out of three kinds of basic particles interacting via three kinds of forces, the physicalistic account by Sean Carroll. This provoked a lively discussion with so far more than forty comments. In this second part I will explain why not everything that exists is just physical, particularly with respect to the existence of meaning.
Is everything just physical? No
The problem of physicalistic views is that we live in a world with many objects that just are not part of physics (as a scientific discipline). Why do we need biology, psychology, economics, or communication science in the first place? Because we do not get very far if we try to observe, understand, and predict the objects of biology, psychology, economics, or communication science in terms basic physical particles such as electrons, protons, and neutrons. It has sometimes been suggested that (ultimately) all disciplines will be translated into physical language, but we do not have good reasons to believe that this is going to happen.
Contrariwise, there are ever more disciplines with ever more complex objects and I doubt that even physics itself with all its branches and sub-disciplines can be translated into one unified theory. Philosophers investigating the concept of reduction found out that reducing one theory to another is anything but a trivial matter; as far as I know, it is rather the exception than the rule in the history of science.
In our everyday world, we deal with literature, headaches, people, political systems, rumors, and so on. Try to define what a headache is without referring to a subject that actually feels the pain; or try to explain fluctuations of the stock market in terms of basic physics. You can possibly describe the text you are reading now in terms of electrons, protons, and neutrons realized at a certain time in a certain place in your computer, but the same text can also be realized in somebody else’s computer at the same time in a different place. It will be the same text with the same meaning, but not the same physical thing.
There are non-physical things
This is not magic, but simply due to the fact that this text and the particles and forces realizing it at some time in a certain place are not identical with each other. There will be very similar physical states in your computer at other times, but none of them will be a realization of this text, not even resemble it closely. In particular, this text has a meaning that you understand if you are a competent speaker of the English language but this meaning is neither a property of the electrons, protons, and neutrons, nor of the forces they are interacting with.
We have a plurality of descriptions of the world and it is one of the major challenges to understand what the relation is between them. If we want to understand and predict human behavior, then psychology as well as other behavioral and social sciences are a good start to begin; if we want to understand and predict markets, then economics might be the best choice (economists did not seem to be very successful with this recently, though, even regarding explanations after the facts).
Perhaps basic physics constrains psychological and economical processes in the sense that psychology and economics must not contradict physics; but this direction is bidirectional: If we know that a certain psychological or economical process occurs, then this constrains physics in the sense that no convincing physical theory can hold that the process cannot not occur.
Compatibility is all we need
So all that we need between the different scientific kinds of descriptions in order to avoid conflicts is that they are compatible with each other, that they do not contradict each other. If we cannot translate psychological or economical happenings into basic physical language, then this is a problem for the physicalist who states that everything, ultimately, is just physical, and not a proof that these happenings do not exist.
In this second part we have seen how implausible it is to assume that only physical things exist and that this view will not get us far in scientific investigation. It is not only the case that there are no physical descriptions available of most of the things in our everyday world, but there are also examples like the case of meaning that can be realized by many physical configurations without being identical to any of them.
In the third and last part I will also discuss causal relationships as they are investigated and found in many sciences, particularly the behavioral and social sciences, and draw a conclusion about the viability of an agnostic stance with regard to science and the search for the soul.