## Section One

WHY DOES ANYTHING EXIST?

## Intuitively, there shouldn't be anything to explain. Bizarrely, this doesn't seem to be the case. One clue to the answer may be our difficulty in rigorously specifying the alternative default state of "nothingness" from which any departure stands in need of an explanation. A dimensionless point? A timeless void? A quantum vacuum? All attempts to specify an alternative reified "nothingness" - an absence of laws, properties, objects, or events - just end up smuggling in something else instead. Specifying anything at all, including the truth-conditions for our sense of "nothingness”, requires information. Information is fundamental in physics. Information is physical. Information, physics tells us, cannot be created or destroyed. Thus wave functions in quantum mechanics don't really collapse to yield single definite classical outcomes. (

INTRODUCTIONcf. Wigner's friend: Wigner's friend). Decoherence - the scrambling of phase angles between the components of a quantum superposition - doesn't literally destroy superpositions. Not even black holes really destroy information. (cf. the black hole information paradox)So naturally we may ask: where did information come from in the first place?

Perhaps the answer is that it didn’t. The total information content of reality is necessarily zero: the superposition principle of QM formalises

inexistence.On this story, one timeless logico-physical principle explains everything, including itself. The superposition principle of quantum mechanics formalises an informationless zero ontology - the default condition from which any notional departure would need to be explained. In 2002,

Physics Worldreaders voted Young's double-slit experiment with single electrons as the "most beautiful experiment in physics". (cf. Double-slit experiment makeover) Richard Feynman liked to remark that all of quantum mechanics can be understood by carefully thinking through the implications of the double-slit experiment. Quite so; only maybe Feynman could have gone further.IfEverettian QM (cf. Everettian quantum theory) is correct, reality consists of a single vast quantum-coherent superposition. Each element in the superposition, each orthogonal relative state, each "world", is equally real. Most recently, the decoherence program in post-Everett quantum mechanics explains the emergence of quasi-classical branches ("worlds") like ours from the underlying quantum field-theoretic formalism. (cf. Wojciech Zurek's Quantum Darwinism) The universal validity of the superposition principle in post-Everett QM suggests that the mystery of our existence has a scientific rather than theological explanation.What does it mean to say that the information content of reality may turn out to be zero? Informally, perhaps consider the (classical) Library of Babel. (

cf. The Library of Babel)The Library of Babel contains all possible books with all possible words and letters in all possible combinations. The Library of Babel has zero information content. Yet somewhere amid the nonsense lies the complete works of Shakespeare - and you and me. However, the Library of Babel is classical. Withdrawing a book from the Library of Babel yields a single definite classical outcome - thereby creating information. Withdrawing more books creates more information. If we sum two ordinary non-zero probabilities, then we always get a bigger probability. All analogies break down somewhere. Evidently, we aren't literally living in Borges’ Library of Babel. So instead of the classical Library of Babel, let us tighten the analogy. Imagine the quantum Library of Babel. Just as in standard probability theory, if there are two ways in QM that something can happen, then we get the total amplitude for something by summing the amplitudes for each of the two ways. If we sum two ordinary non-zero probabilities, then we always get a bigger probability. Yet because amplitudes in QM are complex numbers, summing two amplitudes can yield zero. Having two ways to do something in quantum mechanics can make it not happen. Recall again the double-slit experiment. Adding a slit to the apparatus can make particles less likely to arrive somewhere despite there being more ways to get there. Now scale up the double-slit experiment to the whole of reality. The information content of the universal state vector is zero. (cf. Jan-Markus Schwindt, "Nothing happens in the Universe of the Everett Interpretation": PDF) The quantum Library of Babel has no information.Caveats? Loose ends? The superposition principle has been experimentally tested only up to the level of fullerenes, though more ambitious experiments are planned (

cf. Physicists propose 'Schrödinger's virus' experiment) Some scientists still expect the unitary Schrödinger dynamics will need to be supplemented or modified for larger systems - violating the information-less zero ontology that we're exploring here.Consciousness? Does the superposition principle break down in our minds? After all, we see live or dead cats, not live-and-dead-cat superpositions. Yet this assumption of classical outcomes - even non-unique classical outcomes - presupposes that we have direct perceptual access to the mind-independent world. Controversially (

cf. Max Tegmark critiques quantum mind), perhaps the existence of our phenomenally-bound classical world-simulations itself depends on ultra-rapid quantum-coherent neuronal superpositions in the CNS. For if the superposition principle really broke down in the mind-brain, as classical neuroscience assumes, then we'd at most be so-called "micro-experiential zombies” - just patterns of discrete, decohered Jamesian neuronal “mind-dust” incapable of phenomenally simulating a live or a dead classical cat. (cf. http://www.physicalism.com/#6 This solution to the phenomenal binding problem awaits experimental falsification with tomorrow's tools of molecular matter-wave interferometry. (cf. Non-materialist Physicalism)What about the countless different values of consciousness? How can an informationless zero ontology possibly explain the teeming diversity of our experience? Well, just as the conserved constants in physics cancel out to zero, and just as all of mathematics can in principle be derived from the properties of the empty set, perhaps the solutions to the field-theoretic equations of QFT mathematically encode the textures of consciousness. If we had a cosmic analogue of the Rosetta stone, then we'd see that these values inescapably "cancel out" to zero too. Unfortunately, it's hard to think of any experimental tests for this highly speculative conjecture.

"A theory that explains everything explains nothing", protests the critic of Everettian QM. To which we may reply, rather tentatively: yes, precisely.

* * *

The defence of a zero ontology below was written in 1997. I'd write it rather differently today; but the core conjecture still stands. The conjecture that the superposition principle of QM explains literally everything - from why anything exists at all to the properties of our phenomenally-bound minds - can't be verified. Yet the conjecturecanbe experimentally refuted. Thus any experimentally-detected departure from unitarity in physics, or a negative result from the "Schrödinger's neurons" interferometry experiment outlined in my defence of non-materialist physicalism (2014), would cleanly falsify a zero ontology.

David Pearce (2015).

Some

Puzzling

Coincidences...What is the connection between:1. One's

a prioriintuition that there's no conceivable reason, or even explanation-space, for whyanythingat all exists. [This powerfully felt preconception is hard to express in natural language without spuriously reifying ("turning into a thing") non-existence or Nothingness i.e. asking "Why isn't thereNothingrather thanSomething?" and thus running the risk of lapsing into Heideggerian obscurantism. But see below].2. The quantum-mechanical wave-function of the Universe, the allegedly exhaustive formal description of the world, encodes how

everythingthat physicallycanoccur/existdoesoccur/exist with some density or other. Taken literally, this increasingly popular and deceptively "anything-goes"-sounding interpretation of the quantum formalism actuallyrules outall of the world's traditional cosmologies. This is because of their varying degrees of disguised internal inconsistency. Post-Everett "no collapse" interpretations of QM exclude a lot else besides. For Universal QM is farlesspermissive than it sounds in some ways. Yet tragically - at least to my negative utilitarian mind - its entailment of googolplexes of hell-branches means it is horrifically more prolific in others.3. In the Universe as a whole, the conserved constants (electric charge, angular momentum, mass-energy) add up to/cancel out to exactly

There isn't any net electric charge or angular momentum. The world's positive mass-energy is exactly cancelled out by its negative gravitational potential energy. Provocatively, cryptically, elliptically,zero."nothing"exists. [Whatisso special about the conserved constants? Willeverythinginternal to the universe, and analogously everythinginternalto black holes, turn out to be derivable from the conserved constants; and thus, in a sense to be explicated, be derivable from the properties ofzero?]4. Black holes:

5. The universe can itself be treated, contentiously, as a black/white hole (?? omega = 1, the critical value) Does the universe evaporate "hairlessly" backward/forward to

- have [possible complications aside] "no hair". From an external observer's perspective, they are simply and exhaustively characterised by the conserved constants (internally, on the other hand, they may possess all sorts of properties, e.g. Shakespeare-loving infalling astronauts; you and me?).

- ultimately evaporate via Hawking radiation to
0, or something akin to 0(?).0???? ) [Notes: some non-standard physics:Are the Big Bang and Big Crunch not justtype-identical(?), buttoken-identical?? Is the Big Bang a black hole evaporating??? If the expansion of the universe isn't really accelerating, does the universe have an event horizon in our distant future/past when the (cold) universe (omega=1) is at maximal volume, eventually decaying via Hawking radiation? Are alltime-like and space-like paths closed, entailing that spooky EPR correlations aren't really non-local?? Does the Multiverse 'expand' symmetrically both "backward" and "forward" in time from/to its final/initial low entropy condition (?) - granted that the entropy of a (universal?) black hole is given by the logarithm of the number of microstates consistent with the area of its shrinking/expanding event horizon?]6. Mathematically :

0can/must be construed as (a condition akin to our conception of?) a number.

- The whole of mathematics can, in principle, be derived from the properties of the empty set, Ø. [Since Ø has no members, in the standard set-theoretic definition of natural numbers it can be identified with the number zero, 0. (
this is still problematic; should 0 be regarded, not as the empty set, but as the number of items in the empty set? And what's the ontological status of the empty set?)] The number 1 can be defined as the set containing 0, i.e. simply the set {0} that contains only one member. Since 0 is defined to be the empty set, this means that the number 1 is the set that contains the empty set as a member {Ø}. The number 2 can be understood as the set, {0, 1}, which is just the set {Ø, {Ø}}. Carrying on, the number 3 is defined to be the set {0, 1, 2} which reduces to {Ø, {Ø}, {Ø, {Ø}}} Generalising, the number N can be defined as the set containing 0 and all the numbers smaller than N. Thus N = {0, 1, 2 ...N-1} is a set with N members. Assuming only the concept of the empty set Ø, each of the numbers in this set N can be replaced by its definition in terms of nested sets. Proceeding to derive the rest of maths from the properties of the natural numbers is more ambitious; but it's conceivable in principle. All that then remains to be done is to explain the empty set i.e. why (a condition analogous to our concept of) the empty set must be the case]

- The existence of any number, in virtue of its properties, entails the existence of all the others i.e. a system of mathematics couldn't exist bereft only of the number, say, 42; and the existence of
anynumber, in virtue of the full set of its properties/structural relationships, entails the existence of every other number. Thus there aren't any "atomic" facts in mathematics. Given further that mathematics [Gödelian complications aside] exhaustively and uncannily encodes the world (Wigner's "unreasonable effectiveness" of mathematics in the natural sciences), then perhaps there aren't any "atomic" facts about the world either. The properties of any one thing [0?] entail the properties of all the others.

- Insofar as they are well-defined, the summed membership of the uncountably large set of positive and negative numbers, and every more fancy and elaborate pair of positive and negative real and imaginary etc terms, trivially and exactly cancels out to/adds up to
0. Alternatively: the sum of all infinities - starting at negative infinity and going to positive infinity - is zero. [actually, since there are powerful arguments that the subtraction of same-size infinite cardinals isnotdefined, any 'cancellation'isn'treally trivial. Platonic abstracta are pathological beasts.] Immanent in0is their strict equivalence and consequentintersubstitutivity.(link to Everett?? Net energy etc of Multiverse =0= all possible outcomes) [Yet why not, say, 42, rather than 0? Well, if everything - impossibly, I'm guessing - added up/cancelled out instead to 42, then 42 would have to be accounted for. But if, in all, there is0, i.e no (net) properties whatsoever, then there just isn't anything substantive which needs explaining.]