With human consciousness the universe became aware of itself. It might even be claimed, as the neurophysiologist John Eccles once did, that the universe cannot be said to have existed until there was human consciousness; the universe’s past falling into place only retrospectively. What claim could be more arrogant, or anti-Copernican? Yet if we see reality as a conversation between human consciousness and what we take to be outside ourselves, the arrogance fades away. Other forms of consciousness have their own conversations with the universe.
10 | For Einstein, quantum mechanics only makes sense if there is some hidden variable which, once found, turns the world back into a world of cause and effect.
Without being aware of it … we exclude the subject of cognizance from the domain of nature that we endeavour to understand. We step with our person back into the part of an onlooker who does not belong to the world, which by this very procedure becomes an objective world.
The physicist Erwin Schrödinger (1887–1961) refutes Einstein’s belief in an independent reality
11 | If an observing mouse is a separate physical system, where does the system begin and end? With a few atoms it is clear, because atoms have lost their thingness. Out of pure thought alone, we might guess that a world of elementary particles has to be indistinguishable as things. How would elementary particles know where the boundary of the system is? By the time we reduce the world to atoms, the world has become a place of limited sameness. The molecules of our bodies are continually in motion in and out across our boundaries, they do not know where we start and end. As complex structures of a certain size, humans lose their grip on reality and fall into the illusion of a world of things.
Nature opens its eyes and sees that it exists.
Friedrich Schelling (1775–1854), philosopher
12 | On the radio I hear Simon Saunders, a philosopher of physics, attempting to explain the measurement problem: Look, there’s a fairly straightforward dilemma here, well trilemma really …
13 | In Hugh Everett’s ‘many worlds’ interpretation of 1957, reality is a single wave function, a superposition that never collapses of every state of everything in the entire universe. In the quantum world there is a rule: whatever can happen, happens. The many worlds interpretation of quantum mechanics says that all possibilities contained within the wave equation actually do happen. God does not play dice, all possibilities exist.
We see only part of the wave equation. Other selves see other parts of the wave equation in other parts of the universe. The idea of a coherent self is undermined. What we take to be our self is the illusion that arises out of being trapped in a particular perspective of the multiverse. Somewhere in the multiverse we are doing everything that it is possible for us to do.
14 | Nature is a single superposition. It is only with great effort that scientists create a rival superposition, a rival nature. At any instant Nature pounces to claim its own. The information of our rival laboratory-made superpositions will easily leak into the much larger superposition that is all of nature outside the laboratory. The leaking of this information gives the illusion that the wave collapses, but it is only an illusion: the larger wave absorbs the smaller wave.
Scientists have found ways to keep a molecule made of some twenty carbon atoms in its own superposition (outside the superposition that is Nature). It requires the creation of an extremely cold environment. The small molecule does indeed, under these extreme conditions, reveal its ‘true’ nature: being in two or more places at the same time, for example – behaviour that would have counted as magic less than a hundred years ago.
We are far from working out how to keep something as complex as a cat separate from the superposition that is Nature. I once heard a scientist say that if we look hard enough, one day we might find cats and chairs embedded in the wave equation. Perhaps, but somehow I doubt it.
15 | The chance that all the molecules that make up a glass of water being together as a glass of water in some other part of the universe and not here cancel out all the possibilities of where it could also be, and it ends up being where we most likely take it to be, what we call ‘here’. The rules of quantum mechanics tell us that all possibilities exist, but added together the unlikely ones cancel each other out, leaving what we acknowledge as the possible, the world of things. It is the addition of these possibilities that gives the illusion of a single reality, of a glass of water that exists very close to where we find it.
16 | Heisenberg said that the meaning of quantum mechanics is in the equations. Bohr, his mentor, pointed out that we still have to talk about the equation in words.
Mathematics is a great tool, but the ultimate governing language of science is language.
Lee Smolin
17 | The theoretical physicist David Bohm said that the quantum world is process based. Such a world is most readily described in verbs rather than nouns. He said that the problem with European languages, as in sentences like ‘The cat sat on the mat,’ is that we are dealing with well-defined nouns, a world of things. He believed the process that the verb describes is the deeper reality from which the illusion of thingness emerged, not the other way about. It has been suggested that the Algonquin languages of the Blackfoot, Micmac and Ojibwa tribes are particularly suitable processed-based languages in which to see the world as it is described by quantum mechanics. For these tribes, the world is alive. Singing is generative. The world was sung into existence.
Explanations of processes by which things come to be produce a feeble impression compared with the mystery that lies under the process.
T.S. Eliot (1888–1965), poet and essayist
18 | There are physicists who are still uncomfortable with the world quantum mechanics describes. Many attempts have been made to undermine quantum mechanics as a description of how reality actually is, but all attempts have failed. Pragmatically, scientists all agree that quantum mechanics works, and most don’t worry about how it should be interpreted.
SECTION 9 (#ulink_69f645b8-e422-5c24-91fd-775227596e30)
On time (#ulink_69f645b8-e422-5c24-91fd-775227596e30)
Time flies like an arrow, fruit flies like a banana.
Attributed to Groucho Marx
1 | From our human perspective the universe evolved us over time and through the action of one cause on another, and yet philosophical investigations of the nature of time, and of cause and effect, cast a shadow of physical doubt even here.
2 | Aristotle reasoned that humans cannot escape the chain of cause and effect, and that any chain of cause and effect must eventually find its origin in a first cause. In order to avoid this kind of reasoning he came to the conclusion that the universe must be eternally existent. Some scientists were made uneasy by the Big Bang theory because it isolates a beginning moment for the universe. The multiverse, created out of eternal inflation, randomly and without cause, is an attempt to make the universe once more eternal and uncreated as Aristotle envisioned it. And yet it is a creation story still, and one that will eventually be succeeded by some more refined account.
3 | Out of many possibilities of the quantum world a particular occurrence happens in time. But what is this moment of time in which things happen? How long is a moment? What joins one moment to another?
At the conjuror’s, we detect the hair by which he moves his puppet, but we have not eyes sharp enough to descry the thread that ties cause and effect.
Ralph Waldo Emerson (1803–82), American transcendentalist
4 | Where does a cause end and its effect begin? What surrounds the cause and cuts it off from what it effects? What is in the space in between? What is the time between time? These are thoughts a precocious, gloomy child might have. But not childish; the problems run deep. The Scottish philosopher David Hume (1711–76) tried to pin down the elements of the illusion as a list of propositions that must be fulfilled: the cause and effect must be contiguous in space and time, the cause must come before the effect, there must be constant union between cause and effect; there are five further, increasingly elaborate tenets. Hume’s insight was to see that cause and effect are habits of the mind. We associate two events, two stimuli, two ideas in our minds, and time passes. But if an idea existed truly separate from another, how would we ever move from that idea to the next? We would be attached to the idea forever, unchanging and frozen out of time.
5 | The world is this then this, not this because of this. If there is intention in the universe it is hidden at all levels. Or does not exist.
The very idea of a cause is emergent and abstract. It is mentioned nowhere in the laws of motion of elementary particles and, as philosopher David Hume pointed out, we cannot perceive causation, only a succession of events.
David Deutsch
6 | In Dr Johnson mode, a harrumph is enough to dismiss the problem. I turn on the kettle, the element heats up, the water boils, a cup of tea is made. Causes and effects. We know what a cause is and what an effect is in our world of large things and from our human perspective. At the gross scale of human beings consciousness seeps in, granting us among its manifest powers the power to manifest cause and effect. But from a universal perspective that removes the human, the world must look differently. Pure thought tells us that there can be no gap between cause and effect – what could be in the gap? – but if there is no gap then there is nothing to distinguish cause and effect. Reductive materialism must and does account for this seeming impossibility. Relativity and quantum mechanics are two such accounts. Philosophy is not entirely useless! In relativity and quantum mechanics any exact formulation of what a cause can be is abandoned. Cause and effect are not qualities of the world at quantum scales. At the Big Bang the whole universe was a quantum event. Causality drains from the universe as we rush back towards its beginning. Radioactivity is an effect without a cause; the emergence of the universe from nothing is another example. Cause and effect emerge at human scales.
7 | Newton’s equations might suffice to retrace the path of a ball or of a planet, or predict their future courses, but the ball’s path and the planet’s orbit are not contained in the equations. As powerful as the predictions contained in the equations are, they always describe only some limited part of what is going on. The planet’s orbit might be changed because of some comet not taken account of. The ball may be thrown off course because of some unforeseen gust of wind. As hard as we try to predict what elements of change may arise, to describe any system, completely, we must eventually take account of the whole universe.
All this seemed to have ended well for Evgeny Mikhailovich and the yard porter Vassily: but it only seemed so. Things happened which no one saw but which were more important than all that people did see.
Tolstoy, ‘The Forged Coupon’
So, whatever the verdict of physics, the real causal explanation for why there are boiled eggs is that I, and other breakfasters, intend that boiled eggs should exist.
Alfred Gell (1945–97), anthropologist
8 | Time is an illusion, said the ancient Greek philosopher Parmenides, and the deeper reality is eternal and unchanging.
Now he has departed from this strange world a little ahead of me. That signifies nothing. For us believing physicists the distinction between past, present, and future is only a stubbornly persistent illusion.
Einstein writing, a month before his own death, about the recent death of his lifelong friend Michele Besso
9 | For Einstein the past and future exist eternally. Time does not flow, it just is. In fact all physical theories so far devised – Newtonian mechanics, Einstein’s two theories of relativity, even quantum mechanics – are symmetric in time. No arrow of time is indicated. There is no physical reason why a smashed plate might not rejoin itself, and indeed in some parts of the universe we should expect to see the arrow of time reversed. So far no such evidence has been found. To a material reductionist the arrow of time is an illusion of scale, just as Einstein’s special theory of relativity shows us that it is an illusion that time and space are separate. It is because humans experience the arrow of time that the second law of thermodynamics
was added to physics. By fiat, the second law gives time a direction. The second law of thermodynamics fulfils an observational and psychological need rather than a physical one.
The objective world simply is, it does not happen. Only to the gaze of my consciousness, crawling upward along the world line of my body, does a section of the world come to life as a fleeting image in space which continuously changes in time.
Hermann Weyl (1885–1955), mathematician
The physical world does not have tensed time, in which present, past and future exist side by side.
Raymond Tallis, philosopher
10 | Our human experience of living in the world is of time running forwards. We see a world in which everything, eventually, is ruined by time moving inexorably from past to future via a privileged instant we call now. The past is what the future becomes when it has been pulled through the ring of the present, and the present is the flame that burns the future into the ash of the past. Physical theories do not privilege the ‘now’. Physics tells us that everything that will ever happen in the universe has already happened. The universe simply is. If material reductionists are to hold fast to their theories and the God-like perspective of physics, they must explain why we human beings experience the illusion of an arrow of time, and why the moments of our lives cannot be revisited. Why human beings are consigned to march, once only, second by second, forwards along a line of allotted time is a question so far unanswered by science. Or rather there is no consensus around whatever theories have been put forward.