Above: Clock gears in the Saint Maximus church in Magnac-Laval, Haute-Vienne, France (Krzysztof Golik) [picture cropped] [Information on copyright: https://commons.wikimedia.org/wiki/File:Clock_gears_in_the_St_Maximus_church_in_Magnac-Laval_01.jpg]

In the 20th and 21st centuries, we have made a vast amount of progress in understanding how a physical object, like a brain or computer, could engage in highly sophisticated and seemingly intelligent behavior.  For instance, being able to strategize and plan ahead in the way necessary to play games like chess and Go at high levels seems to be a sign of intelligence, and yet purely physical objects — computers — can beat all humans.  Furthermore, we have gained significant empirical data for how the function of the physical stuff in our heads — the brain — affects our thinking.  Should we conclude that we ourselves are purely physical objects, and that the brain is the mind?

I will sketch arguments — none of them particularly original — that there are four phenomena that resist such a reduction of humans to the physical: meaning, consciousness, normativity and free will.  This resistance does not appear to be something that we can overcome with more scientific research.  There is good reason to doubt that any tenable theory of these phenomena could be confined to the physical.

Meaning

The progress of human knowledge, especially in science, requires the periodic introduction of new technical vocabulary.  Some of these words had a prior non-technical meaning and came to have a new technical meaning.  For instance, “cell” originally was used to indicate the small rooms of monks and nuns, and when Robert Hooke in the 17th century saw some biological entities under his microscope that resembled small rooms, he gave the word a new technical meaning.  On other occasions, a completely new word is made up, such as “gluon” in physics.

In both cases, something needs to be done to explain the word: it doesn’t have the new meaning in some innate way.  To give meaning to a new word or a new meaning to an old word, we need to use old words or gestures — e.g., pointing to the cells under a microscope  — to define or point out what the word means.  These old words or gestures must themselves have a prior meaning, or else they won’t give meaning to the new word.

The point generalizes.  A purely physical thing — a sound in the air, ink marks on a page, or the movement of an object — does not have an innate meaning.  When we point with our index finger, we indicate the most salient object lying beyond the finger along the ray from the knuckle to the fingertip.  But animals like us could have used the same gesture to indicate an object in the opposite direction, or to do something completely different from indicating an object, say to express joy.

Thus, if a purely physical thing has a meaning, it gets that meaning from something else that is meaningful.  If that something else is itself physical, it must have gotten its meaning from something else physical and meaningful.  We now have three possibilities: either we have an infinite regress of meaningful physical things, a circularity of meaningful physical things, or something that gives meaning and isn’t itself physical.

Circularities are absurd.  Whether infinite regresses are possible, on the other hand, has been a matter of philosophical discussion for centuries.  However, we do not need to resolve that philosophical question.  In the case of meaning, we can just turn to science. The only meaningful physical things we have are ones that are connected with life (words, gestures, inscriptions, thoughts, perceptions, etc.), and there is no infinite regress of life on earth—earth life began about four billion years ago.

That leaves only one option: there is something that gives meaning and isn’t itself physical.  What is this?  Here, there is room for speculation, but there is a point of logic. This source of meaning is either found in humans or goes beyond humans.  If it is found in humans, it follows that humans are not completely physical — and that is what I was arguing for.

If, on the other hand, the source of meaning goes beyond humans, then we need more speculation.  What could be a source of meaning for human language and gesture without being itself completely physical?  Probably our best hypothesis here is God.

Thus, the meaning line of thought points either to something like a soul in humans or to God — or both.  While I am convinced that God exists, I find it philosophically and theologically attractive to suppose the source of meaning for humans is found in humans themselves.  And this requires humans not to be wholly physical.  Moreover, if there is a God, and he created us, then we may well be in his image, and that also points to us not being wholly physical.

We can go back to the beginning observation that physical objects like computers can play chess and Go.  That observation needs to be qualified.  To really play chess or Go, one needs to act intentionally.  One hasn’t started a chess game if one walks by a set-up chessboard and one’s hand accidentally brushes the king’s pawn forward by two spaces.  To play a game, one needs to act with the intention to play the game.  And to have that intention, one must have a thought about the game, namely a thought whose meaning concerns the game.  Without meaning, there is no play.  Computers do not play games, as they do not have meaningful thoughts.  But they do very impressive things that are behaviorally like extremely sophisticated game-play.

Consciousness

When I am falling during a rock-climbing session, I feel the temporary weightlessness until the rope grabs me.  I feel this by means of an accelerometer in my inner ear. Now, my phone has an accelerometer as well, and with appropriate software it can detect and react to falls as well as I can.  But there is a difference: my phone doesn’t feel weightlessness, isn’t conscious of it, while I am.  We thus have a distinction between merely detecting and really feeling.

But while I am superior to my phone in what I feel, since the phone feels nothing, my phone has some superiority in what it detects.  For instance, it detects radio waves with its multiple antennas, while I do not.  But neither I nor my phone feel radio waves.  I wonder what it would be like to feel radio waves (we can easily imagine an alien who does so).  What do 2.4 GHz electromagnetic waves, for instance, feel like?  I have little idea, just as a color-blind person doesn’t know how green and red differ to a person with full trichromat vision.

Suppose, however, that Google advertises that its latest Pixel phone’s AI is so sophisticated that its sensors not only detect but consciously feel or experience.  If the advertising is correct, the phone now exceeds me not just in what it detects, but in what it feels or experiences: it feels 2.4 GHz radio waves.  Now, I have little idea of what a “2.4 GHz wave experience” is like, but like many people in academia, I suffer from a surfeit of curiosity.  Imagine that curiosity about what the “2.4 GHz experience” is like impels me to pore over schematics to the phone’s electronics and carefully read every line of the phone’s code. Would this satisfy my curiosity about “2.4 GHz experience”?

Surely not.  While I am not an engineer, as an amateur I already have a pretty good sense of what I would see: transistors combined into logic gates, logic gates combined into larger computational units, a large amount of complex program logic, and some interesting electronics in the radio receivers.  The engineer’s knowledge is more sophisticated, but not different in kind.  And no amount of knowledge of this kind will tell one what a “2.4 GHz experience” is like, and how something’s subjective feeling of it differs from its feeling of 5 GHz waves, and so on.

But a phone presumably is nothing but electronics and software.  If I know its electronics and software, I know all there is to know about it.  Yet we have just seen that by knowing all of its electronics and software, I still wouldn’t know what the “2.4 GHz experience” is like.  Assuming the phone really does have such experiences, we now have a contradiction: I know everything about the phone and I don’t know everything about the phone. Since contradictions can’t be true, I can conclude that the hypothetical advertising of the phone as conscious is false.  A phone couldn’t consciously experience anything, since if it could, we could know what its feelings are like by knowing its electronics and software, but knowing electronics and software tells you nothing like that.

We can conclude that no purely electronic device can have conscious experiences.  The argument, however, extends to any purely physical object: we can know all there is to know about it, and we still won’t know what it’s experiences are like, what the world looks like “from its point of view.”  And the reason is that no purely physical object can have consciousness.  But we have consciousness.  So we are not purely physical objects. (The philosophical reader will recognize this as Frank Cameron Jackson’s black-and-white Mary argument.)

Note that my argument started with the presumption that a phone is “nothing but electronics and software.” It could be that I am wrong, and that a sufficiently sophisticated computer would get a soul, implausible as that might sound.  In that case, by knowing all there is to know about the electronics and software, we wouldn’t know all there is to know about the computer, since we wouldn’t know its soul, and the argument would allow the computer to be conscious.  But that only confirms my point: an entity needs to transcend the physical to be conscious.

Normativity

There are objective norms for how we should behave.  Moral norms are a particularly vivid example: a human who murders, cheats and steals is a bad human.  But some people dispute the objectivity of moral norms.  So I will focus on epistemic norms, norms about how one should think.  For example, in our thinking we should follow evidence.  We should prefer simpler to more complex theories.  We should aim for consistency.  We should not believe things just because want them to be true.

Could one say that the epistemic norms are subjective, a matter of taste or social convention?  That is not plausible.  That our belief should track the truth seems to be a part of the very concept of belief.  Following the best science rather than conspiracy theories is not just a matter of societal or individual preference.

Now, norms say how things should be.  Physics tells us how things are.  No amount of investigation of the physical constitution of an object will by itself tell us what the object should do, but only what it actually does.  Thus, norms go beyond physical reality.

This is enough to show that physical reality is not all of reality.  But does it follow that humans are more than physical?  Here we want to distinguish between two different relationships that a norm can have to something: the norm can be extrinsic or intrinsic.  If an engineer designs a bridge to carry a certain weight, then the bridge should carry that weight.  But this “should” is not defined by something intrinsic to the bridge: it is defined by the design specifications of the bridge.  One can have two bridges that are exact physical twins, but one is defective and the other is properly functioning, because their design specifications are different: one was supposed to be able to carry 50 tons, and it breaks down at 10, while the other was supposed to be able to carry 2 tons, and works up to 10.  This is extrinsic normativity, since the “supposed to” is defined by the people specifying the requirements for the bridge. All the cases we know of extrinsic normative are ones where the norms come from something outside of the thing imposing some rules.

Some theists think that our moral norms are extrinsic because they are grounded in God’s will or command.  In the Catholic tradition, the dominant (but not exclusive) view, instead, is the natural law view that our moral norms are grounded in human nature (though of course God creates us with this nature) and hence are intrinsic to us.  But whatever one thinks about moral norms, the idea that our epistemic norms are extrinsic to us is not particularly plausible.  Imagine, for instance, that God commands us: “Follow the evidence in your thinking.” Is it really plausible that if God did not issue the command, we wouldn’t need to follow the evidence in our thinking?  For instance, if God did not issue the command, wouldn’t we still need to examine the evidence to see if God perhaps has issued such a command?  And, further, the very concept of thought seems to presuppose that thought reaches at truth through evidence.

The obligation to follow the evidence and think reasonably is thus, very plausibly, grounded in our own selves.  But if our own selves are purely physical, then this would be impossible, since purely physical things are described without remainder by physics, and physics deals with what is and not what should be.  So we have a non-physical normative component of the human being which defines norms for our behavior.  Is it perhaps the soul?

Free will

Immanuel Kant observed that we can all recognize our guilt in various wrongful actions.  But the only way we can be guilty is if we are responsible for the wrongdoing, and the only way we can be responsible for anything is if we have free will.  Thus, all of us have clear evidence of our free will available to us.

Some philosophers like Galen Strawson and neuroscientists like Benjamin Libet have called free will into question.  But now put some specific argument against free will in parallel with Kant’s argument for free will.  Kant’s argument is based on one nearly undeniable observation — that we are guilty — and the nearly undeniable principle that a being without free will is not guilty of anything.  That I am guilty of certain things is such a central feature of my experience of the world that if this awareness were always a delusion then I shouldn’t be able to trust my other intuitions, such as the mathematical or statistical principles that underlie the practice of modern science.  Once we get into the business of treating what is evident to us as a universal human delusion, we are on the road to large-scale skepticism, and are undercutting science.  Similarly, the principle that freedom is needed for guilt is more plausible than any of the philosophical principles invoked in arguments against freedom.

Now, if we are, without remainder, beings controlled by physics, then it seems we do not have free will. It does not matter whether the physics is deterministic or not, as in either case the source of our actions is particles and fields whose behavior is outside of our control.  Thus, freedom requires that we transcend the physical.

Conclusions

Our life is one of meaning, consciousness, normativity and responsibility.  Each of these things points towards us as beings that transcend the physical.  How exactly we transcend the physical is a much harder philosophical question.  Contemporary non-materialist philosophers differ on whether we have souls or whether we are physical things with added-on properties that transcend those studied by physics.  I opt for the soul view, but that is indeed a matter for further discussion.

[Alexander R. Pruss is Professor of Philosophy at Baylor University. He has a Ph.D. in Mathematics from the University of British Columbia and in Philosophy from the University of Pittsburgh. He has over 125 scholarly publications in mathematics, philosophy and interdisciplinary work in both areas. His philosophical research areas includes metaphysics, philosophy of religion, ethics, formal epistemology and philosophy of mathematics. His books include The Principle of Sufficient Reason: A Reassessment, One Body: An Essay in Christian Sexual Ethics, and Infinity, Causation, and Paradox. He regularly blogs at AlexanderPruss.blogspot.com. On a personal note, he holds two indoor rock climbing Guinness World Records.]