I was asked to write up a pithy summary of the upshot of this paper. This is the best I could manage.

One of the most remarkable features of the world we live in is that we can make measurements that are consistent across space and time. By "consistent across space" I mean that you and I can look at the outcome of a measurement and agree on what that outcome was. By "consistent across time" I mean that you can make a measurement of a system at one time and then make the same measurement of that system at some later time and the results will agree.

It is tempting to think that the reason we can do these things is that there exists an objective reality that is "actually out there" in some metaphysical sense, and that our measurements are faithful reflections of that objective reality. This hypothesis works well (indeed, seems self-evidently true!) until we get to very small systems, where it seems to break down. We can still make measurements that are consistent across space and time, but as soon as we stop making measurements, then things start to behave very differently than they did before. The classical example of this is the two-slit experiment: whenever we look at a particle we only ever find it in one particular place. When we look continuously, we see the particle trace out an unambiguous and continuous trajectory. But when we don't look, the particle behaves as if it is in more than one place at once, a behavior that manifests itself as interference.

The problem of how to reconcile the seemingly incompatible behavior of physical systems depending on whether or not they are under observation has come to be called the measurement problem. The most common explanation of the measurement problem is the Copenhagen interpretation of quantum mechanics which postulates that the act of measurement changes a system via a process called wave function collapse. In the contemporary popular press you will often read about wave function collapse in conjunction with the phenomenon of quantum entanglement, which is usually referred to as "spooky action at a distance", a phrase coined by Einstein, and intended to be pejorative. For example, here's the headline and first sentence of the above piece:

More evidence to support quantum theory’s ‘spooky action at a distance’

It’s one of the strangest concepts in the already strange field of quantum physics: Measuring the condition or state of a quantum particle like an electron can instantly change the state of another electron—even if it’s light-years away." (emphasis added)

This sort of language is endemic in the popular press as well as many physics textbooks, but it is demonstrably wrong. The truth is that measurement and entanglement are actually the same physical phenomenon. What we call "measurement" is really just entanglement on a large scale. If you want to see the demonstration of the truth of this statement, read the paper or watch the video or read the original paper on which my paper and video are based. Or go back and read about Von Neumann measurements or quantum decoherence or Everett's relative state theory (often mis-labeled "many-worlds") or relational quantum mechanics or the Ithaca interpretation of quantum mechanics, all of which turn out to be saying exactly the same thing.

Which is: the reason that measurements are consistent across space and time is not because these measurements are a faithful reflection of an underlying objective reality. The reason that measurements are consistent across space and time is because this is what quantum mechanics predicts when you consider only parts of the wave function and ignore other parts.

Specifically, it is possible to write down a mathematical description of a particle and two observers as a quantum mechanical system. If you ignore the particle (this is a formal mathematical operation called a partial trace of an operator matrix ) what you are left with is a description of the observers. And if you then apply information theoretical operations to that, what pops out is that the two observers are in classically correlated states. The exact same thing happens for observations made of the same particle at two different times.

The upshot is that nothing special happens during a measurement. Measurements are not instantaneous (though they are very fast ) and they are in principle reversible, though not in practice.

The final consequence of this, the one that grates most heavily on the intuition, is that your existence as a classical entity is an illusion. Because measurements are not a faithful reflection of an underlying objective reality, your own self-perception (which is a kind of measurement) is not a faithful reflection of an underlying objective reality either. You are not, in point of metaphysical fact, made of atoms. Atoms are a very (very!) good approximation to the truth, but they are not the truth. At the deepest level, you are a slice of the quantum wave function that behaves, to a very high degree of approximation, as if it were a classical system but is not in fact a classical system. You are in a very real sense living in the Matrix, except that the Matrix you are living in is running on a quantum computer, and so you -- the very close approximation to a classical entity that is reading these words -- can never "escape" the way Neo did.

As a corollary to this, time travel is impossible, because in point of metaphysical fact there is no time. Your perception of time is caused by the accumulation of entanglements in your slice of the wave function, resulting in the creation of information that you (and the rest of your classically-correlated slice of the wave function) "remember". It is those memories that define the past, you could even say create the past. Going "back to the past" is not merely impossible it is logically incoherent, no different from trying to construct a four-sided triangle. (And if you don't buy that argument, here's a more prosaic one: having a physical entity suddenly vanish from one time and reappear at a different time would violate conservation of energy.)

In another message, I suggested that, given how many cultures we have to borrow from, that our language may include multiple words from various sources that apply to a single concept.

An example is Reality, or Existence, or Being, or Universe, or Cosmos, or Nature, ect.

Another is Subjectivity, Mind, Consciousness, Experience, Qualia, Phenomenal, Mental, ect

Is there any problem with accepting these claims so far? Curious what case would be made to the contrary.

(Here's a bit of a contextual aside, between quantum mechanics and cosmology, the words "universe", "multiverse", and "observable universe" mean at least 10 different things, depending on who you ask. People often say the Multiverse comes from Hugh Everett. But what they are calling the multiverse, Everett called "universal wave function", or "universe". How did Everett's universe become the Multiverse? DeWitt came along and emphasized some part of the wave function branching into different worlds. So, if you're following, one Universe, many worlds. Over the next few decades, this idea was popularized as having "many parallel universes", which is obviously inaccurate. Well, a Scottish chap decided to correct this. He stated the Universe was the Universal Wave Function, where it was "a complete one", because that's what "uni" means. And that our perceived worlds of various objects is a "multiverse". One Universe, many Multiverses. Again, the "parallel universes" idea seemed cooler, so as it became more popular the Multiverse became one and the universe became many. What's my point? The use of these words is legitimate fiasco, and I suggest we abandon them altogether.)

If these claims are found to be palatable, what do they suggest?

I propose, respectfully and humbly as I can imagine there may be compelling alternatives presented here, that in the 21st century, we make a decision about which concepts are necessary, which term we will use to describe that concept, and respectfully leave the remaining terms for the domain of poetry.

Here are the words I think we need:

1. reality
2. model
3. absolute
4. relative
5. subjective
6. objective
7. measurement
8. observer

With these terms I feel we can construct a concise metaphysical framework, consistent with the great rationalists of history, and that accurately described Everett's "Relative State Formulation of Quantum Mechanics".

1. Absolute reality is what is. It is relative to no observer. It is real prior to measurement.
2. Subjective reality is what is, relative to a single observer. It exists at measurement.
3. Objective reality is the model relative to all observers. It exists post-measurement.

Everett's Relative State formulation, is roughly this:

1. The wave function is the "absolute state" of the model
2. The wave function contains an observer and their measurement apparatus
3. An observer makes a measurements and records the result in a memory
4. those measurement records are the "relative state" of the model

Here we see that the words multiverse and universe are abandoned for absolute and relative states, which is actually the language used in the Relative State Formulation.

My conclusion then, for you consideration and comment, is that a technical view of reality can be attained by having a select set of terms, and this view is not only consistent with themes of philosophy (which I didn't really explain) but also the proper framework in which to interpret quantum mechanics (ala Everett).

(I'm not sure how familiar everyone here is with Everett specifically or not. His thesis depended on "automatically function machines" that make measurements with sensory gear and record them. After receiving his PhD, he left theoretical physics, and had a life long fascination with computer vision and computer hearing. That suggests to me, the reason his papers have been largely confounding to the general physicists, is because they didn't realize the extent to which Everett really thought he could mathematically model an observer.)

I should note, it may clarify things to add another term "truth", though this would in general be taken as an analog of "real". For example, if something is absolute true, then it is of absolute reality. If something is objectively true, then it is of objective reality. The word "knowledge" in this sense is a poetic word for objective truth, understood on the premise that objective truth is not absolute truth.

A new study indicates that people become more utilitarian (save more lives) when viewing a moral dilemma in a virtual reality situation, as compared to reading the same situation in text.

Abstract.

Although research in moral psychology in the last decade has relied heavily on hypothetical moral dilemmas and has been effective in understanding moral judgment, how these judgments translate into behaviors remains a largely unexplored issue due to the harmful nature of the acts involved. To study this link, we follow a new approach based on a desktop virtual reality environment. In our within-subjects experiment, participants exhibited an order-dependent judgment-behavior discrepancy across temporally-separated sessions, with many of them behaving in utilitarian manner in virtual reality dilemmas despite their non-utilitarian judgments for the same dilemmas in textual descriptions. This change in decisions reflected in the autonomic arousal of participants, with dilemmas in virtual reality being perceived more emotionally arousing than the ones in text, after controlling for general differences between the two presentation modalities (virtual reality vs. text). This suggests that moral decision-making in hypothetical moral dilemmas is susceptible to contextual saliency of the presentation of these dilemmas.

Full paper

Video of simulations

This relates to my recent post on existence in many-worlds. 

I care about possible people. My child, if I ever have one, is one of them, and it seems monstrous not to care about one's children. There are many distinct ways of being a possible person. 1)You can be causally connected to some actual people in the actual world in some histories of that world. 2)You can be a counterpart of an actual person on a distinct world without causal connections 3)You can be distinct from all actual individuals, and in a causally separate possible world. 4)You can be acausally connectable to actual people, but in distinct possible worlds.

Those 4 ways are not separate partitions without overlap, sometimes they overlap, and I don't believe they exhaust the scope of possible people. The most natural question to ask is "should we care equally about about all kinds of possible people". Some people are seriously studying this, and let us hope they give us accurate ways to navigate our complex universe. While we wait, some worries seem relevant: 

 

1) The Multiverse is Sadistic Argument:

P1.1: If all possible people do their morally relevant thing (call it exist, if you will) and

P1.2: We cannot affect (causally or acausally) what is or not possible

C1.0: Then we cannot affect the morally relevant thing. 

 

2) The Multiverse is Paralyzing  (related)

P2.1: We have reason to care about X-Risk

P2.2: Worlds where X-Risk obtains are possible

P2.3: We have nearly as much reason to worry about possible non-actual¹ worlds where X-risk obtains, as we have to actual worlds where it obtains. 

P2.4: There are infinitely more worlds where X-risk obtains that are possible than there are actual¹

C2.0: Infinitarian Paralysis 

¹Actual here means belonging to the same quantum branching history as you. If you think you have many quantum successors, all of them are actual, same for predecessors, and people who inhabit your Hubble volume. 

 

3) Reality-Fluid Can't Be All That Is Left Argument

P3.1) If all possible people do their morally relevant thing

P3.2) The way in which we can affect what is possible is by giving some subsets of it more units of reality-fluid, or quantum measure

P3.3) In fact reality-fluid is a ratio, such as a percentage of successor worlds of kind A or kind B for a particular world W

P3.4) A possible World₃ with 5% reality-fluid in relation to World₁ is causally indistinguishable from itself with 5 times more reality-fluid 25% in relation to World_2. 

P3.5) The morally relevant thing, though by constitution qualitative, seems to be quantifiable, and what matters is it's absolute quantity, not any kind of ratio. 

C3.1: From 3.2 and 3.3 -> We can actually affect only a quantity that is relative to our world, not an absolute quantity. 

C3.2: From C3.1 and P 3.5 ->  We can't affect the relevant thing. 

C3.3: We ended up having to talk about reality fluid because decisions matter, and reality fluid is the thing that decision changes (from P3.4 we know it isn't causal structure). But if all that decision changes is some ratio between worlds, and what matters by P3.5 is not a ratio between worlds, we have absolutely no clue of what we are talking about when we talk about "the thing that matters" "what we should care about" and "reality fluid".

 

These arguments are here not as a perfectly logical and acceptable argument structure, but to at least induce nausea about talking about Reality-Fluid, Measure, Morally relevant things in many-worlds, Morally relevant people causally disconnected to us. Those are not things you can Taboo the word away and keep the substance around. The problem does not lie in the word 'Existence', or in the sentence 'X is morally relevant'. It seems to me that the service that that existence or reality used to play doesn't make sense anymore (if all possible worlds exist or if Mathematical Universe Hypothesis is correct). We attempted to keep it around as a criterial determinant for What Matters. Yet now all that is left is this weird ratio that just can't be what matters. Without a criterial determinant for mattering, we are left in a position that makes me think we should head back towards a causal approach to morality. But this is an opinion, not a conclusion. 

 

Edit: This post is an argument against the conjunctive truth of two things, Many Worlds, and the way in which we think of What Matters.  It seems that the most natural interpretation of it is that Many Worlds is true, and thus my argument is against our notion of What Matters. In fact my position lies more in the opposite side - our notion of What Matters is (strongly related to) What Matters, so Many Worlds are less likely.  

 

 

 

 

 

There are at least ten different conceptions of how the World can be made of many worlds.

But are those just definitional disputes? Or are they separate claims that can be evaluated. If they are distinct, in virtue of what are they distinct. Finally, do we have good grounds to care (morally) about those fine distinctions?

 

Max Tegmark's taxonomy is well known here. 

Brian Greene's is less, and has 9, instead of four, kinds of multiverse, I'll risk conflating the Tegmark ones that are superclasses of these, feel free to correct me:

In his book, Greene discussed nine types of parallel universes:

• (Tegmark 1) The quilted multiverse only works in an infinite universe. With an infinite amount of space, every possible event will occur an infinite amount of times. However, the speed of light prevents us from being aware of these other identical areas.
• (Tegmarks 1 and 2) The inflationary multiverse is composed of various pockets where inflaton fields collapse and form new universes.
• The brane multiverse follows from M-theory and states that each universe is a 3-dimensional brane that exists with many others. Particles are bound to their respective branes except for gravity.
• The cyclic multiverse has multiple branes (each a universe) that collided, causing Big Bangs. The universes bounce back and pass through time, until they are pulled back together and collided again, destroying the old contents and creating them anew.
• (Tegmarks 2) The landscape multiverse relies on string theory's Calabi-Yau shapes. Quantum fluctuations drop the shapes to a lower energy level, creating a pocket with a different set of laws from the surrounding space.
• (Tegmarks 3) The quantum multiverse creates a new universe when a diversion in events occurs, as in the many-worlds interpretation of quantum mechanics.
• The holographic multiverse is derived from the theory that the surface area of a space can simulate the volume of the region.
• (Related to Bostrom's Simulation Hypothesis) The simulated multiverse exists on complex computer systems that simulate entire universes. (for the sake of brevity I'll consider dust theory to be a subset of this)
• (Tegmark's 4) The ultimate multiverse contains every mathematically possible universe under different laws of physics.

I don't understand branes well enough (or at all) to classify the others. The holographic one seems compatible with a multitude, if not all, previous ones. 

Besides all those there is David Lewis's Possible Worlds in which all possible worlds exist (in whichever sense the word exist can be significantly applied, if any). For Lewis, when we call our World the Actual World, we think we mean the only one that is there, but what we mean is "the one to which we happen to belong".  Notice it is distinct from the Mathematical/Ultimate in that there may be properties of non-mathematical kind. 

So Actual_lewis= Our world  and Actual_{most everyone else}=Those that obtain, exist, or are real. 

The trouble with existence, or reality, is that it is hard to pin down what it is pointing at. Eliezer writes:

The collection of hypothetical mathematical thingies that can be described logically (in terms of relational rules with consistent solutions) looks vastly larger than the collection of causal universes with locally determined, acyclically ordered events. Most mathematical objects aren't like that. When you say, "We live in a causal universe", a universe that can be computed in-order using local and directional rules of determination, you're vastly narrowing down the possibilities relative to all of Math-space.

So it's rather suggestive that we find ourselves in a causal universe rather than a logical universe - it suggests that not all mathematical objects can be real, and the sort of thingies that can be real and have people in them are constrained to somewhere in the vicinity of 'causal universes'. That you can't have consciousness without computing an agent made of causes and effects, or maybe something can't be real at all unless it's a fabric of cause and effect. It suggests that if there is a Tegmark Level IV multiverse, it isn't "all logical universes" but "all causal universes".

and elsewhere

More generally, for me to expect your beliefs to correlate with reality, I have to either think that reality is the cause of your beliefs, expect your beliefs to alter reality, or believe that some third factor is influencing both of them.

Now another interesting way of looking at existence or reality is  

Reality=I should care about what takes place there

It is interesting because it is what is residually left after you abandon the all too stringent standard of "causally connected to me", which would leave few or none of the above, and cut the party short.  

So Existence_yud  and Existence_{moral-concern} are very different. Reality-fluid, or Measure, in quantum universes is also different, and sometimes described by some as the quantity of existence. Notice though that the Measure is always a ratio - say these universes here are 30% of the successors of that universe, the other 70% are those other ones - not an absolute quantity.

Which of the 10 kinds of multiverses, besides our own, have Existence_yud  Existence_{moral-concern} and which can be split up in reality-fluid ratios?

That is left as an exercise, since I am very confused by the whole thing...

 

Hey all - I typed this out to help me understand, well... how to understand things:

 

Mental clarity is the ability to read reality accurately. 

 

I don't mean being able to look at the complete objective picture of an event, as you don't have any direct access to that. I'm talking about the ability to read the data presented by your subjective experience: thoughs, sights, sounds, etc. Once you get a clear picture of what that data is, you can then go on and use it to build or falsify your ideas about the world.

This post will focus on the "getting a clear picture" part.

I use the word "read" because it's no different than reading from a book, or from these words. When you read a book, you are actually curious as to what the words are saying. You wouldn't read anything into it that's not there, which would be counterproductive to your understanding.

 

You just look at the words plainly, and through this your mind automatically recognizes and presents the patterns: the meaning of the sentences, their relation to the topic, the visual imagery associated with them, all of that. If you want to know a truth about reality, just look at it and read what's there.

Want to know what the weather's like? Look outside - read what's going on.

Want to know if the Earth revolves around the Sun, or vice versa? Look at the movement of the planets, read what they're doing, see which theory fits better.

Want to check if your beliefs about the world are correct? Take one, read the reality that the belief tries to correspond to, and see how well they compare.

This is the root of all science and all epiphanies.

But if it's so simple and obvious, why am I talking about it?

It's not something that we as a species often do. For trivial matters, sure, for science too, but not for our strongly-held opinions. Not for the beliefs and positions that shape our self-image, make us feel good/comfortable, or get us approval. Not for our political opinions, religious ideas, moral judgements, and little white lies.

If you were utterly convinced that your wife was faithful, moreso, if you liked to think of her in that way, and your friend came along and said she was cheating on you, you'd be reluctant to read reality and check if that's true. Doing this would challenge your comfort and throw you into an unknown world with some potentially massive changes. It would be much more comforting to rationalize why she still might be faithful, than to take one easy look at the true information. It would also more damaging.

Delusion is reading into reality things which aren't there. Telling yourself that everything's fine when it obviously isn't, for example. It's the equivalent of looking at a book about vampires and jumping to the conclusion that it's about wizards.

Sounds insane. You do it all the time. You'll catch yourself if you're willing to read the book of your own thoughts: flowing through your head, in plain view, is a whole mess of opinions and ideas of people, places, and positions you've never even encountered. Crikey!

That mess is incredibly dangerous to have. Being a host to unchecked or false beliefs about the world is like having a faulty map of a terrain: you're bound to get lost or fall off a cliff. Reading the terrain and re-drawing the map accordingly is the only way to accurately know where you're going. Having an accurate map is the only way to achieve your goals.

So you want to develop mental clarity? Be less confused, or more successful? Have a better understanding of the world, the structure of reality, or the accuracy of your ideas? 

Just practice the accurate reading of what's going on. Surrender the content of your beliefs to the data gathered by your reading of reality. It's that simple.

 

It can also be scary, especially when it comes to challenging your "personal" beliefs. It's well worth the fear, however, as a life built on truth won't crumble like one built on fiction.

 

Truth doesn't crumble.

 

Stay true.

Further reading:

Stepvhen from Burning true on truth vs. fantasy.

Kevin from Truth Strike on why this skill is important to develop.