I've read a lot of neuroscience/neurophilosophy books. But none like "Phi: A Voyage from the Brain to the Soul," by psychiatrist Giulio Tononi.
It's amazingly creative, filled with literary, historical, artistic, philosophical, and scientific allusions that made me feel like a Neanderthal. How the heck does Tononi know all this stuff? Guess I spend way more time watching The Daily Show and Survivor than he does.
In the lavishly illustrated book, a blend of theory, fact and fiction, Galileo meets Francis Crick, Alan Turing, Charles Darwin, and other great thinkers. It's pleasingly entertaining, yet left me feeling like I'd eaten only the frosting on a cake of consciousness explanation, not the substantial part.
That's to be expected, though. Nobody can explain what consciousness is.
Much is known about how the brain functions, but what philosophers call the "hard problem" of consciousness, how and why we have phenomenal experiences, remains a mystery. The mechanism of sight is well understood; about all that can be said about the subjective experience of seeing is Wow.
Tononi argues that consciousness is integrated information.
Integrated information is the information generated by a system above its parts, where the parts are those that, taken independently, generate the most information... Consciousness lives within a system where integrated information reaches a maximum, inside its own drop.
...Integrated information measures how much can be distinguished by the whole above and beyond its parts, and phi is its symbol. A complex is when phi reaches its maximum, and therein lies one consciousness -- a single entity of experience.
If that doesn't make a lot of sense to you, join the club. I struggled with the ideas also. But the gist of what Tononi is saying resonates with me.
Consciousness is a continuum. A thermostat is extremely minimally conscious, in that it processes basic information. So is a diode, frequently mentioned by Tononi, which can only distinguish light from dark (one bit of information).
The human brain is vastly more complex. Clusters of neurons, billions upon billions, are constantly talking with each other, exchanging information. Thus people have a very high "phi" compared to a thermostat. The exact ratio can't be calculated, as this is way beyond current neuroscientific capabilities.
Our neurons are basically fancy photodiodes, producing electric bursts in response to incoming signals. But the conscious experiences they produce contain far more information than in a single diode. In other words, they reduce much more uncertainty. While a photodiode can be in one of two states, our brains can be in one of trillions of states. Not only can we tell the difference between a Chaplin movie and a potato chip, but our brains can go into a different state from one frame of the movie to the next.
“One out of two isn’t a lot of information, but if it’s one out of trillions, then there’s a lot,” Dr. Tononi said.
Consciousness is not simply about quantity of information, he says. Simply combining a lot of photodiodes is not enough to create human consciousness. In our brains, neurons talk to one another, merging information into a unified whole. A grid made up of a million photodiodes in a camera can take a picture, but the information in each diode is independent from all the others. You could cut the grid into two pieces and they would still take the same picture.
Consciousness, Dr. Tononi says, is nothing more than integrated information. Information theorists measure the amount of information in a computer file or a cellphone call in bits, and Dr. Tononi argues that we could, in theory, measure consciousness in bits as well. When we are wide awake, our consciousness contains more bits than when we are asleep.
Tononi's phi theory doesn't offer any support for the existence of an immaterial soul. He's clear that when the integrated information in a brain disappears upon a person's death, so does consciousness.
By contrast, most religions seem to view soul as something exceedingly simple: partless, whole, a conscious drop with an affinity for god's ocean. Well, maybe. There's just no evidence for this. Tononi writes:
They all had thought there was the body, and then there was the soul. And consciousness could not but side with soul. Oh yes, his body may perish for eternity -- burdened with age and broken in its joints -- damaged goods already, it had betrayed his soul. But the soul, how could it rot?
A consolation unworthy of a thinking man. For when the earthly Galileo would die, which Galileo should have survived in spirit?
...He thought back to what he had seen. Experience vanished with a mere blow to the head: one day Copernicus's soul had dissolved together with his brain. Every day his own soul ebbed and flowed with sleep and wake in his own brain.
...So consciousness was born with the brain, flourished when the brain grew its green connections, pruned and refined them to build the scaffold through which the shape of qualia bloomed, and then had aged with it, the green canopy wilting, and soon enough the soul would die when the brain went dry.
Yes, consciousness did not reduce to matter -- phi was the most intrinsically irreducible thing there is, the only thing that's really real. But consciousness did rely on matter, and if the brain was undercut, the soul too would collapse.
So why had he believed that the soul could escape death? Why had Dante believed it, conjuring clouds of spirits to yawn incurious sameness where all was stale eternally? Why Newton -- born the year of his death, to enchain the universe to laws of his devising?
Not faith, but lack of imagination. Unable to imagine how the perfection of the body could be built out of random variation and selection, they fancied a dexterous demiurge. Unable to imagine how the lute's ethereal sound could spring forth from the brain's dull matter, they fancied a transcendent soul, a soul set there to listen, a soul that would spring free with death.
...Perhaps as long as no explanation could be imagined, as long as science was unequal to the task, the soul could still survive in its secret sanctuary. But if consciousness too yielded to reason, then, like a fog swept by a cold wind, the mystery would dissolve, and death was certain.
Perhaps. Because he had been wrong before. Tides proved the earth revolves around the sun, he thought then, but he was wrong. Perhaps the soul divorced the body when it was betrayed. And pehaps the sun revolved around the earth.
So Tononi's theory of phi doesn't provide the pleasing consolation of eternal life that a religious belief in soul, spirit, and god does. On the plus side, Tononi offers up a much more likely explanation for conscious experience.
Then what is integrated information, a fundamental property of the world?
"As fundamental as matter, perhaps more," said Alturi, "and perhaps the same thing -- it from bit. For phi is the fountain of phenomena."
...I will tell you what I think I have learned, said Galileo. I have learned that information only exists if there is a difference that makes a difference. For how would anything exist, if nothing can make a difference to it? How could it exist, if it has no choice -- an element with only one probable state?
I have learned that information and causation are one and the same thing, and that is all there is: what exists must be a difference that makes a difference, a choice that's causal.
..."To know how much the world is in the image and likeness of our brain, it is enough to carry out your first experiment, to fall asleep and dream. What we dream of is what we know, what we can know is that of which we dream.
The world can be imagined within, but not seen naked from without. And yet without the inner glow of consciousness, there would be no sight. What we must do is go and seek the light, the light that unifies."
(If you want a lot more detail, and less poetry, check out this paper by Tononi.)