Brian Greene’s Physicalist Approach to History and Consciousness

Big history is a specific approach to history that examines the universe and the human story at its largest possible scales, from the big bang to the present to the distant future. It seeks to unify all physical, biological, psychological, and historical events within a single explanatory framework, often reductionist in nature. Since everything in such a history is claimed to be ultimately reducible to the laws of physics (in the reductionist versions), such a narrative seems particularly suited for a theoretical physicist to tell. 

Enter Brian Greene and his latest foray into the field of big history, Until the End of Time. There’s no question that Greene is well-suited for the task; in addition to his deep expertise in theoretical physics, he also has the unmatched ability to clearly explain complex scientific concepts. The beginning chapters are a testament to this, as Greene takes the reader through the origins of the universe to the present day by explaining—with a liberal dose of clever analogies—how the fundamental concepts of entropy, energy, and evolution guide the physical, chemical, and biological processes that make up our world. 

While some may find this narrative approach (which is conspicuously devoid of anything “supernatural” or “divine”) depressing, others (like me) will find it utterly fascinating and even, in a sense, liberating. Greene shows us that by contemplating the universe at its largest scales—and by recognizing the impermanence of everything—we can come to more deeply appreciate our fleeting moments on this earth. And, even more importantly, we can learn to embrace the responsibility we all have to create our own meaning in our lives, while avoiding the somewhat childish view that meaning has to be imposed on us from above for life to have any value. 

As the book progresses, however, things get murkier. Philosophically, one thing you can say about Greene is that he is consistent in his reductionist stance. Greene believes that everything can be explained—at least theoretically—with reference only to the laws and motions of fundamental particles. He does admit, however, that the prospect of actually doing this is virtually impossible, as the human mind (and for that matter any computer) does not have the cognitive or computational capacity to make such calculations.  

The eruption of a volcano, the causes of the second World War, and your inner experiences and emotions, for example, could be explained by physical laws, it’s just that we don’t have the capability of doing so. This is why we must study geological phenomena, history, and psychology at different, emergent levels, levels that we can cognitively handle. But this doesn’t mean that, in reality, it’s not “physics all the way down,” which Greene unabashadely believes. 

This qualified reductionist approach, however persuasive it appears, runs into its biggest challenge in the chapter on consciousness. In fact, it is here that I believe Greene’s philosophy is most subject to criticism. 

To say that consciousness is reducible to the motions of particles is to not fully appreciate the difference between scientific explanation and experience itself. Thomas Nagel, in his famous essay, What Is It Like to Be a Bat?, neatly elucidates the problem. As Greene wrote:

“Since our mode of engagement with the world is profoundly different [from the bat], there is just so far our imagination can take us into the bat’s inner world. Even if we had a complete accounting of all the underlying fundamental physics, chemistry, and biology that make a bat a bat, our description would still seem unable to get at the bat’s subjective “first-person” experience. However detailed our material understanding, the inner world of the bat seems beyond reach. What’s true for the bat is true for each of us.” 

This demonstrates, at least to me, that there is another aspect to consciousness that is clearly not of a physical nature (also see the philosophical experiment “Mary’s Room”). What does it even mean to say that a thought, or the experience of the color red, is physical? Science advances by ignoring subjective experience and by quantifying the objects of experience. It is therefore a mistake to think that science can turn in on consciousness and quantify it in the same manner, without any major intellectual revolution in how we see the world. 

Well, Brian Greene seems to think that all we need is more physics and neuroscience and we can finally understand, not only what it is like to be a bat, but our own consciousness. This, despite the fact that every advance in neuroscience gets us no closer to understanding consciousness than the ancient Greeks. I’m just not convinced that more of the same is going to make any difference (or how it even could make any difference).  

In regard to possible intellectual revolutions, Greene mentions panpsychism but fails to mention the Interface Theory of Perception, which says that the relationship between our perceptions and reality is like the relationship between a desktop interface and a computer. According to this theory, we have for centuries been under the impression that science investigates the natural world when all it has been investigating is the “virtual desktop” of the brain, which tells us as much about the natural world as our computer interface tells us about the circuits of the computer. This, I believe, may be a promising line of research but will fundamentally alter the way we think about reality (see The Case Against Reality by cognitive scientist Donald Hoffman).    

Next, Greene addresses free will, telling us, unsurprisingly, that it is an illusion. Since he already told us that consciousness is simply the physical arrangement of particles in our brain, then it follows that our thoughts and actions are entirely determined by physical laws. His physicalism forces him to this conclusion, but, as we saw, if he’s wrong about consciousness, he could also be wrong about free will. 

The reader should keep in mind that if free will is bound up with consciousness—and if we don’t yet have a coherent scientific account of consciousness—then we don’t yet have a coherent scientific account of free will. Therefore, there is little compulsion for me to jettison my own belief in some form of free will—based on the totality of my experience—on the basis of a scientific explanation that doesn’t exist.  

It’s also worth considering the implications of Greene’s position, if he is right and our behavior is entirely physically determined. If Greene is right, it means that the big bang set off a mathematically-defined, predetermined course for every particle in the universe, some of which would eventually coalesce into the solar system, earth, life, humans, minds, and eventually Brian Greene, who would write a book telling you, the reader, that your subjective experience of free will is actually an illusion that you can’t help but thinking due to this very sequence of events. 

If he is right, of course, this is pretty amazing, especially since that would mean that the physical laws have conspired over billions of years so that he, Brian Greene, can serve as the messenger of such a profound insight. But I think you can forgive me for thinking that this may not be the case. Consciousness and free will are still open questions that we are nowhere near understanding.

There is one further point that no scientist or physicalist has ever, as far as I know, adequately addressed. It is this: If everything is determined, and free will doesn’t exist, and no conscious creatures could have acted otherwise than they did, then what function does consciousness serve? If everything is predetermined by the laws of physics, then what good does it do me (or any conscious creature) to have the illusion of choice? 

Stated another way, if physical processes produce consciousness, but consciousness does not have a reciprocal effect on physical processes, then consciousness is entirely inept at impacting any outcome whatsoever. Therefore, if we follow Greene in his physicalism, consciousness completely loses its evolutionary rationale.