From Stars to Brains: Conference Dinner Talk

by George Ellis

Presented at From Stars to Brains, MCH conference in honor of Paul Davies, Canberra, 20-21 June 2006

I am delighted to be here to celebrate the work of Paul Davies, and to consider with you the conference theme of From Stars to Brains.

The extraordinary nature of emergence:

• Stars galaxies planets
• Life on earth: jumping spiders, bees, birds;
• Humanity and all its achievements
• Technology: running hot water, flush toilets: motor cars and aircraft; computers the internet and Google

Its three faces: in terms of the human brain

• function, how does mind arise our of protons and electrons?
• development, how does mind develop through reading DNA?
• evolution, how did this all come about in historical terms? From an almost featureless primeval universe to this banquet hall?

Additionally,

• context: how did the context come to be right to let this all happen? (cosmology, astrophysics, planetary physics)

2: The main argument: do the higher levels have real causal power?

The pro argument from cosmological history:

Physics and chemistry have made tremendous progress in understanding the nature of the world around us. The atomic theory of matter and periodic table of chemical elements enables understanding of the physical nature of material objects, including living beings. Quantum theory illuminates the physical basis of the periodic table and the nature of chemical bonding. Molecular biology shows how complex molecules underlie the development and functioning of living organisms, while neurophysics illuminates the functioning of the brain. In the hierarchy of complexity, there are links from each level to the one above, from chemisty to biochemistry, to cell biology, physiology, psychology, and then sociology/economics/politics, with particle physics the foundational subject underlying - and so in some sense explaining - all the others. On a reductionist worldview, physics is all there is. The Cartesian picture of man as machine seems to be vindicated.

However this view omits important aspects of the world that physics has yet to come to terms with. We live in an environment dominated by objects embodying the outcomes of intentional design (buildings, books, computers, teaspoons). Physics has nothing to say about the intentionality resulting in existence of such objects, even though this intentionality is clearly causally effective. This is a simple statement of fact - there is no physics theory that explains the nature of, or even the existence of, football matches, teapots, or jumbo jet aircraft. The human mind is physically based, but of such complexity there is no hope whatever of determining its behaviour from the underlying physical laws. Even if we had a satisfactory fundamental physics “Theory of Everything” this situation would remain unchanged: physics would still fail to comprehend human purpose, and hence would provide a predictively incomplete description of the real world around us.

Can one nevertheless claim that the underlying physics causally determines uniquely what happens, even if we can’t predict the outcome? To examine if this is so, contemplate what is required for this to occur when placed in its proper cosmic context. The implied claim is that the particles that existed at the time of decoupling of the Cosmic Background Radiation in the early universe, whose positions and velocities were the initial data for what exists today, were placed precisely so as to make it inevitable that fourteen billion years later, human beings would exist, Townes would conceive of the laser, Witten would develop string theory. Is it really plausible that quantum fluctuations in the inflationary era in the very early universe, the source of the perturbations at the time of decoupling, implied future inevitability of the Mona Lisa and Einstein’s Theory of Relativity? Those fluctuations are supposed to have been random, which by definition means they do not encode any purpose or meaning.

However such meaning did indeed come into being. Ever‑higher levels of interaction and causality arose as complexity spontaneously increased in the expanding universe, allowing life to emerge. Biological information, originating via Darwinian processes of natural selection, guided the physical development of living systems, including the brain. It is plausible that what actually happened was the contextual emergence of complexity: the existence of human beings and their creations was not uniquely implied by the initial data on the last scattering surface in the early universe, rather the underlying physics together with that initial data created a context that made their existence possible. Conditions at the time of decoupling of matter and radiation fourteen billion years ago were such as to lead to the eventual development of minds that are autonomously effective, able to create higher-level order such as the Hubble Space Telescope and Gödel’s Incompleteness Theorem - embodying purpose and meaning that did not exist at any earlier time.

On this view, the higher levels in the hierarchy of complexity have autonomous causal powers, functionally independent of lower-level processes. Top-down causation takes place as well as bottom-up action, with higher-level contexts determining the outcome of lower level functioning and even modifying the nature of lower level constituents. Stored information plays a key role, resulting in non-linear dynamics that is non-local in space and time. Brain functioning is causally affected by abstractions such as the value of money, the rules of chess and the theory of the laser. These abstractions are realised as brain states in individuals, but are not equivalent to them Maxwell’s theory of electromagnetism is not the same as any individual’s brain state. Although such concepts are causally effective, they are not themselves physical variables. Consequently physics per se can't causally determine the outcome of human creativity, rather it creates the possibility space allowing human intelligence to function autonomously.

This situation is not dependent specifically on human intentionality. Physics by itself cannot comprehend any behaviour that is adaptive and depends on context, for example beaver dam-building and the dances of bees. It is plausible these too emerge at late times in the expanding universe as higher-level autonomous behaviours, made possible but not causally determined by the underlying physics and chemistry.

If this is the case, the challenge to physics is to develop a realistic description of causality in truly complex hierarchical structures, with top-down causation and memory effects allowing autonomous higher levels of order to emerge with genuine causal powers. Attempts to relate physics to complexity so far – such as the reaction-diffusion equation, chaos theory, the renormalisation group, `complexity theory’ - take us only a small step on this road.

Response from some eminent colleagues: it’s only a problem of practice but is doable in principle: physics underlies everything, you just need powerful enough computers to do the job. In the end we are all just machines.

3: The proof this can’t be must be so is form the implications of quantum uncertainty in an evolutionary context

If we fine-grained to the smallest possible scales and collected all the available data, could we then determine uniquely what is going to happen? No, we can’t predict to the future in this way because of foundational quantum uncertainty relations, apparent for example in radioactive decay (we can’t predict precisely when a nucleus will decay and what the velocities of the resultant particles will be) and the motion of a stream of particles through a pair of slits onto a screen (we can’t predict precisely where a photon or electron will end up on the screen). It is a fundamental aspect of quantum theory that this uncertainty is unresolvable: it is not even in principle possible to obtain enough data to determine a unique outcome of quantum events. This unpredictability is not a result of a lack of information: it is the very nature of the underlying physics.

The fact that such events happen at the quantum level does not prevent them from having macro-level effects. Many systems can act to amplify them to macro levels, including photomultipliers (whose output can be used in computers or electronic control systems). Quantum fluctuations can change the genetic inheritance of animals and so influence the course of evolutionary history on Earth. Indeed that is in effect what occurred when cosmic rays – whose emission processes are subject to quantum uncertainty - caused genetic damage in the distant past: The near universality of specialized mechanisms for DNA repair, including repair of specifically radiation induced damage, from prokaryotes to humans, suggests that the earth has always been subject to damage/repair events above the rate of intrinsic replication errors …. radiation may have been the dominant generator of genetic diversity in the terrestrial past. Consequently the specific evolutionary outcomes on life on Earth (the existence of dinosaurs, giraffes, humans) cannot even in principle be uniquely determined by causal evolution from conditions in the early universe, or from detailed data at the start of life on Earth. Quantum uncertainty prevents this, because it significantly affected the occurrence of radiation-induced mutations in this evolutionary history. The specific outcome that actually occurred was determined as it happened, when quantum emission of the relevant photons took place: the prior uncertainty in their trajectories was resolved by the historical occurrence of the emission event, resulting in a specific photon emission time and trajectory that was not determined beforehand, with consequent damage to a specific gene in a particular cell at a particular time and place that cannot be predicted even in principle.

Furthermore there can be an amplification of quantum uncertainty to astronomical scales, indeed this has already happened in the expanding universe at very early times. According to the standard inflationary model of the very early universe, we cannot predict the specific large-scale structure existing in the universe today from data at the start of the inflationary expansion epoch, because density inhomogeneities at later times have grown out of random quantum fluctuations in the effective scalar field that is dominant at very early times: Inflation offers an explanation for the clumpiness of matter in the universe: quantum fluctuations in the mysterious substance that powered the [inflationary] expansion would have been inflated to astrophysical scales and therefore served as the seeds of stars and galaxies. Thus the existence of our specific Galaxy, let alone the planet Earth, was not uniquely determined by initial data in the very early universe. The quantum fluctuations that are amplified to galactic scale by this process are unpredictable in principle.

It follows that the details of the talk I am now giving cannot be predicted from initial data in the very early universe because neither the existence of the specific planet Earth, nor of any human beings at all on Earth, is guaranteed by the details of that initial data. Consequently the specific outcomes of the actions of any particular human being on the planet Earth - such as the words of this talk - certainly cannot be uniquely implied by that data. They are an outcome of emergent complexity arising much later.

Moral: Reductionism is wonderful in terms of what is has led us to understand, but is only part of the story. Emergence of complexity with true causal powers is another major part

4: This has taken place in a cosmological context (From Stars to Brains)

Science enables us to understand much of how we got here

• Martin Harwit: Astrophysical concepts

In a sense each of us has been inside a star; in a sense each of us has been in the empty space between stars; and – if the universe ever had a beginning – each of us was there! Every molecule in our bodies contains matter that once was subjected to the tremendous temperatures and pressures at the center of a star. That is where the iron in our red blood cells originated. The oxygen we breathe, the carbon and nitrogen in our tissues and the calcium in our bones also were formed through the fusion of smaller atoms at the centre of a star. Terrestrial ores containing uranium, plutonium, lead, and many other massive atoms must have been formed in a supernova explosion – the self-destruction of a star in which a sun’s mass is hurled into space at huge velocity. In fact most of the matter on earth and in our bodies must have gone through such a catastrophe!

5: This discussion gives the context of our existence

All a fascinating intellectual exercise, but also is important in terms of how we understand ourselves:

• Star Maker, Olaf Stapledon [1937].

“I perceived that I was on a little round grain of rock and metal, filmed with water ands air, whirling in sunlight and darkness. And on the skin of that little grain, all the swarms of men, generation by generation, had lived in labour and blindness, with intermittent joy and intermittent lucidity of spirit. And all their histories, with its folk-wanderings, its empires, its philosophies, its proud sciences, its social revolutions, its increasing hunger for community, was but a flicker in one day in the lives of the stars.”

Perceiving this can be a transformatory experience

• The Story of An African Farm, Olive Schreiner [Chapter XII: p 96-97].

"He opened the door and went out into the starlight. He walked with eyes bent to the ground, but overhead it was one of those brilliant southern nights when every space so small that your hand might cover it shows fifty cold white points, and the Milky Way is a belt of sharp frosted silver. He mounted the ladder steps. From those he clambered with some difficulty onto the roof of the house. It was of old rotten thatch with a ridge of white plaster, and it crumbled away under his feet at every step. He trod as heavily as he could. So much the better if he fell ... He lifted the black damp hair from his knit forehead, and looked around to cool his hot face.

Then he saw what a regal night it was. He knelt silently and looked up. A thousand eyes were looking down at him, bright and cold. There was laughing irony in them. " So hot? So bitter? So angry? Poor little mortal!" He was ashamed. He folded his arms, and sat on the ridge of the roof looking up at them. "So hot, so bitter, so angry?" It was as though a cold hand had been laid upon his throbbing forehead, and slowly they began to fade and grow dim. .. the burnt book, the broken machine, the box in the loft, he himself sitting there - how small they all became. Even the grave over yonder. Those stars that shone up above so quietly, they had seen a thousand such little existences, a thousand such little existences fight just so fiercely, flare up just so brightly, and go out; and they, the old, old star shone on forever. `We', said the stars, `have seen the earth when it was young. We have seen small things creep out upon its surface - small things that prayed and loved and cried very loudly, and then crept under it again. But we,' said the stars, `are as old as the Unknown.

He leaned his chin against the palm of his hand and looked up at them. So long he sat there that bright stars set and new ones rose, and yet he sat on. Then at last he stood up .. What did it matter about the books? The lust and the desire for them had died out. If they pleased to keep them from him, they might. What matter? It was a very little thing. Why hate, and struggle, and fight? Let it be as it would."

6: Does this all mean we are insignificant and in the end life is without meaning, just a random chance event in the vast emptiness of space?

No. It should not cause us to cease from wonder and appreciation of the miracle of what has occurred:

• The Miracle of Mindfulness. Tich Nhat Hanh:

“I like to walk alone on country paths, rice plants and wild grasses on both sides, putting each foot down on the earth in mindfulness, knowing that I walk on the wondrous earth. In such moments, existence is a miraculous and mysterious reality.

People usually consider walking on water or in thin air a miracle. But I think the real miracle is not to walk on water or in thin air, but on earth. Every day we are engaged in a miracle which we don't even recognise: a blue sky, white clouds, green leaves, the black, curious eyes of a child - our own two eyes. All is miracle.”

• Flight to Arras, Antoine de St. Exupery :

“I say to myself as I watch the niece, who is very beautiful: in her this bread is transmuted into melancholy grace. Into modesty, into a gentleness without words. ….

Sensing my gaze, she raised her eyes towards mine, and seemed to smile .. A mere breath on the delicate face of the waters, but an affecting vision. I sense the mysterious presence of the soul that is unique to this place. It fills me with peace, and my mind with the words: `This is the peace of silent realms’.

I have seen the shining light that is born of the wheat.”

It is my concern that in the technical discussion we do not lose sight of this wonder and mystery. No scientific investigation can in the end unravel the underlying mystery. It can clarify the marvelous mechanisms in action in a wonderful way; but not penetrate the deep nature of existence. We need to look at the deepest nature of humanity and our existence to approach such issues and not fall prey to reductionist tendencies to deny the wonderful nature of our existence: the deep poverty of the “nothing but” approach.

7: Conclusion

It is a pleasure to be here to celebrate discussion of such issues with such an interesting group of people, and to do so in the context of a celebration of Paul’s achievements.

Gfre 2006

Appendix: Nature of reality actual existence of infinities?

Often proclaimed, e.g. chaotic inflation, Susskind: The cosmic landscape

People don’t take infinity seriously: treat it as a large number but it is nothing of the sort

• quote Life in the Infinite Universe argument

It is much more plausible that infinity does not actually occur in the real universe:

- it is a mathematical rather than physical idea (Hilbert)

In any case: whatever theories one may have in this regard, they are certainly not testable.

• First you can’t see all these other claimed expanding universe domains and have no evidence whatever about there actual existence: to summarise, Mt Stromlo will never see them

• Second, if you cold see them you could still not prove there was an infinite number because you could not count them: by its very nature it is impossible to ever count an infinite number of things because that will take an infinite amount ot time: you never come to the end. That is the essential nature of infinity.

So, despite the confidence with which this is often stated, see Rees, Susskind, Tegmark, Linde, it is not science it is metaphysics: it is a totally untestable and unprovable claim.

It is being pursued for ideological reasons, and takes one outside of the domain of testable science. That is fine, as long as it is admitted.