Multiverse

A new ontology offers an alternative to the Many Worlds idea

1st Edition. Copyright © 2019 by David Stringer. https://www.eobar.org

Introduction

Multiverse or Many Worlds is an ontology that tries to avoid a paradox that arises if Quantum Physics is believed to be describing ordinary active matter. It will be assumed that the reader is already familiar with the essentials of Multiverse. It will also be assumed that the reader has read about the New Ontology in "It So Happens" to be found at www.eobar.org.

The Trilemma of Physics

The main argument for Multiverse is that it resolves a trilemma of physics. There are three premises or propositions of physics that cannot all be correct.

P1: Measurements always have definite outcomes

Premise One, which I will call P1, is that measurements always have definite outcomes. That is, scientists have never measured something and found that it is in a superposition of quantum states. Such superpositions are apparent, for example, in the well known two-slit experiment. The interference pattern is said to be the result of quantum entities arriving at the absorber in a superposition of the two states: via-left-slit and via-right-slit. Yet whenever a measurement is performed of one of those entities traversing the slits, it is never found to be in that mixed state. In fact, mixed states have never been measured in any experiment, not just the classic two-slit set up. So by inductive reasoning, there is overwhelming evidence that measurements always have definite (not mixed state) outcomes.

P2: Linearity of time evolution of quantum states

The second, P2, is the premise of linearity of time evolution of quantum states. Taking the two-slit apparatus as an example: Given that states via-left-slit and via-right-slit both exist, then state left-slit-plus-right-slit must also exist. That's linearity. But the linearity of time evolution says more. It says that apparatus-before plus entity-before should evolve to apparatus-after plus entity-after. That's a clumsy way to put it but essentially it is saying that if the measured thing evolves to a mixed state, the whole measuring system (apparatus plus measured thing) should evolve to a mixed state. This says that we should measure mixed states. Since we do not, P2 contradicts P1. Nevertheless, evidence for P2 is that the mathematical equations of quantum mechanics show it to be so. And Quantum Mechanics is probably our most precise and best tested physics ever!

P3: Quantum Theory is complete

The third, P3, is the premise that Quantum Theory is complete. This might be thought of as the rejection of hidden variables. Essentially, it says that quantum theory is fundamental. There isn't something deeper going on with its own variables and equations from which quantum physics emerges. Backing for this premise comes mostly from Bell's Inequality. This has been confirmed by experiments and shows that no local-hidden-variable theory could reproduce quantum mechanics. But note the word "local" which essentially means: without anything, even information, travelling faster than light.

Back to the two-slit experiment. P3 tells us that Quantum Mechanics models everything that is going on in the experiment. P2 tells us that the whole experimental system is in a mixed state whenever the measured entities are in a mixed state. P1 tells us that any measurement will yield a left-slit or right-slit answer but never a mix of both. The question is then: which one of these three premises must be wrong? Clearly they cannot all be right. Either the mixed state is measured (P1 is wrong) or Quantum Mechanics is wrong (P2 is wrong) or Quantum Mechanics is incomplete (P3 is wrong).

Many people, including Einstein, have said that obviously P1 cannot be wrong because it is what we actually observe. We always measure definite outcomes. But the evidence for the correctness of P2 and P3 is so overwhelming to some that , however mad it may seem, they conclude that P1 must be wrong. Multiverse proposes a way for P1 to appear correct for we conscious observers while actually being wrong from a different perspective.

Multiverse offers one solution to the trilemma

What Multiverse offers is another way to think about what happens when a measuring system evolves to a supposedly mixed state. Instead of thinking of it as one reality somehow existing in both states, think of it as one reality branching into two versions of itself, one version in one state and the other version in the other state. We, being part of the universe, also branch. So there is one version of us where state A occurred and another version where state B occurred. Each version of us observes P1 intact and, providing we accept this Multiverse idea, each version of us can accept that P2 and P3 are intact, though on a broader scale that we cannot observe. Taking the two-slit experiment again: When there is interference, we find ourselves in a version of the universe in which the entity really went via one slit (even though we have no way to know which) but we assume that there is another version of the universe in which the entity really went through the other slit.

It is hard not to laugh at this Multiverse idea because it seems so mad. Yet one has to admit that it is a valid solution to the trilemma portrayed, in which one premise must be wrong. Multiverse proponents might argue that it is the only valid solution to the trilemma. However, I propose that the new Ontology put forward in "It So Happens" is also a valid solution.

A new ontology offers a different solution

In the new ontology, the roles of things and events are reversed. We usually think of things (matter) as fundamentally existing and think of events as abstractions, something that happens to things. The new ontology has events as what exists and has things (quantum entities) as abstract concepts. These abstractions are part of a process that evolves the consequences of past events into the actualities of new events. Within the process, abstract consequences are in superpositions of states. But when an actual event occurs, it will always be in a definite state. The mixed states are known as Potentialities whereas the events are known as Actualities.

How does the new Ontology overcome this trilemma? Premises P2 and P3 pertain in Potentialities but P1 does not. Specifically, P2 pertains because Potentialities are a universal superposition of states (of potential contributions to events). Linearity of the time evolution of potential quantum states applies in Potentialities. Indeed, all of Potentialities except new Consequences (of new events) are in a mixed state. And P3 pertains because Potentialities evolve from one moment to the next according to the laws of Quantum Mechanics... completely. Quantum Mechanics is complete, at least in the sense that P3 means. Critically, Potentialities are not distributed in spacetime. Quite the contrary; spacetime is an abstract concept within Potentialities. "Collapse" of Consequences to form an event does not involve faster-than-light motion. Bell's Inequality is not violated.

In the new Ontology, premise P1 only pertains in Actualities. But Actualities is the world that we directly experience. We are patterns of events. We experience and measure events. Potentialities are at a lower level that we cannot access directly because measurements are events. Yet we can discern a great deal of knowledge about Potentialities by analysing the unfolding patterns of events. The variables of Potentialities are not hidden; at least, no more so than the variables of Quantum Mechanics are hidden. After all, Quantum Mechanics has the variables in Schroedinger's equation evolving throughout a two-slit experiment even though we only measure the outcomes. We see that P2 and P3 must pertain throughout the experiment yet we cannot measure the variables throughout. This is just as true in the New Ontology.

Conclusions

So the New Ontology is offered as a valid alternative to the Multiverse ontology. Both ontologies overcome the trilemma but in different ways. Whereas Multiverse treats superposition as a branching of states of continuously present active matter entities, the new Ontology retains the simpler unbranched superpositions of states, but of abstract entities that are only potential contributions to actual events. In a two-slit experiment, Potential Consequences really are affected by both slits! Consequences of past events are not committed to a definite state until they contribute to a new event. The world that we experience and measure are actual events, not the superpositions of potentialities from which they emerge. Every actual event has a definite single state. Every measurement is (or is a consequence of) an Actuality, an actual event. There is a causal link between past and current events and this link is modelled completely by Quantum Mechanics when applied to Potentialities.

The Ontology presented in "It So Happens" is, therefore, a valid alternative to the Multiverse ontology as a solution to the given trilemma of physics. Whether it is a better solution is for others to assess. But the argument that Many Worlds is the only solution no longer applies.