Below is my list of what I see as the deepest mysteries. 

What would you add to the list?

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LIST OF DEEP MYSTERIES ABOUT THE NATURE OF REALITY

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1. THE UNIVERSE

1.1 Eternity – Will our universe last forever? If it won’t, what will the end of the universe be like (e.g., a new big bang, a big crunch, time simply ending, something else)?

1.2 Genesis – Did our universe have a “starting point” (in a pre-existing expanse of time) or has it existed forever, or did time begin when the universe began?

1.3 Geometry – Does the universe extend infinitely in all directions, or is it finite? (To get a feel for how it might be finite without requiring a boundary, consider that the universe could be like the game Pac-Man, topologically – in the sense that, traveling long enough in any direction, you eventually get back to where you started). Is empty space perfectly flat (e.g., like an infinite plane but in multiple dimensions), or does the universe have implicit curvature (e.g., like the surface of a universe-sized orange)?

1.4 Constraints – Could the laws of physics be any different than they are, or is there some reason they have to be this way? Why are there the particular elementary particle types that we find (e.g. electrons, quarks, neutrinos, etc.) with the particular properties they have? Why are there the particular forces we find (e.g. electromagnetism, gravity, the strong nuclear force, etc.) with the particular properties they have?

1.5 Entropy – Why was our universe in a low entropy state in the distant past (with the matter fairly uniformly spread out, rather than, for example, all condensed into black holes)?

1.6 Reason – What’s the right explanation for WHY our universe came to exist? If it was not created by any form of intelligence, is the question even coherent to ask? If it was created by some form of intelligence, was it God, or some other form of intelligent beings (e.g. aliens creating a universe simulation in some vast computer)? If there was an intelligent creator, what is the nature of that creator (e.g. what is that creator like, what does that creator care about, etc.)?

1.7 Uniqueness – Are there other universes besides our own?

1.8 Travel – Are wormholes (connecting different parts of spacetime) actually possible? Is time travel forbidden by the laws of physics? Is instant teleportation impossible?

1.9 Dimensionality – How many dimensions of spacetime are there? (e.g., the standard view is four dimensions, which come from three spatial dimensions and a single time dimension, whereas ‘string theory’ suggests more, though most of those extra dimensions are believed to be really tiny/compact)

1.10 Computability – Can the universe be simulated to arbitrary accuracy on a normal computer (given sufficiently large amounts of memory and time), or is there something “incomputable” about the universe?

1.11 Expansion – Why does the universe seem to be expanding at an accelerating rate? If dark energy exists (the hypothesized element that is believed to make up most of the energy of the universe, not to be confused with dark matter), then what is it and why is it there?

1.12 Dark Matter – Does dark matter actually exist (i.e., the hard to detect element that appears to make up most of the mass in the universe)? If so, what is it made of?

1.13 Unification – How can general relativity and quantum mechanics be combined into a consistent theory that generalizes both (e.g., to model what happens when extremely tiny things are in strong gravitational fields)? Is ‘string theory’ the right path towards unifying general relativity and quantum mechanics (as many physicists believe), or is it a misguided approach (as a few physicists argue)?

1.14 Energy – Is there a positive, zero, or negative total amount of energy in the universe?

1.15 Divisibility – Are space and time infinitely divisible, or are there truly minimum lengths and durations?

1.16 Aliens – Does intelligent life (or even non-intelligent life) exist elsewhere in the universe? If intelligent life does exist elsewhere in the universe, why does it appear not to have reached us yet? Will we ever encounter life that has non-earth origins?

1.17 Life – Why does our universe have a set of physical laws and physical constants that allow for life (and consciousness) to exist at all? Some people argue that if the strengths of the basic forces of physics (like gravity) had been more than a certain increment stronger, or more than a certain increment weaker, life could not have formed in our universe.

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2. HUMANITY

2.1 Origin – What were the first “replicating entities” that all the humans today eventually developed from? Many religions say that God placed the first humans here, who eventually gave birth to all the others. But as for non-religious (evolutionary) explanations, there are various theories about what these replicating entities might have been (e.g., crystals, or special molecules that can make other molecules they bump into look like themselves)

2.2 Extinction – When will humanity go extinct? And what will cause humanity’s extinction?

2.3 Governance – Given the flaws and limitations of our species, and our current state of technology, what systems of governance, laws, and institutions would maximize human flourishing?

2.4 Happiness – Given the current state of the world, and the nature of and resources of one particular person, if that person wants to maximize their happiness, what should they do? What would a supremely intelligent being tell a human about how to become happier?

2.5 Qualia – Do humans have different internal experiences in cases where we typically assume them to have the same experience? For example, do there exist non-visually impaired people whose internal experiences of red (e.g., when looking at a red apple) are totally different than each other? For instance, could it be that one person’s experience of red is what another person experiences as blue? Or even that one person experiences reds as being somewhat more like what someone else experiences for blue things?

2.6 Humor – Why do humans have humor? There are many theories (e.g., “benign violation theory” and “superiority theory”) but none of them seem complete/comprehensive.

2.7 Music – Why do humans love music so much? It’s hard to understand this from an evolutionary perspective.

2.8 Yawning – Why do we yawn? And why are yawns contagious (i.e., seeing someone yawning tends to make others yawn)? There are various theories (e.g., to cool down the brain, or to get more oxygen). My preferred highly speculative explanation is that it’s a mechanism for groups to sync their sleeping, but it’s really hard to know if that’s right.

2.9 Nutrition – What should we do to not merely stave off malnutrition, but to thrive and be as healthy as possible? There seems to be a disturbing lack of consensus on this question (and it may turn out to depend a lot on individual people’s genetic and behavioral differences).

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3. KNOWLEDGE

3.1 Induction – is there a sound argument in favor of using induction that is non-circular (i.e., that doesn’t implicitly rely on using induction to make the argument)?

3.2 Occam’s Razor – Is there a sound justification for Occam’s razor (by which I mean the claim that “simpler” explanations are more likely to be true). If so, what’s the right notion of simpleness for a hypothesis that doesn’t require making arbitrary choices (e.g., avoiding the issue Kolmogorov complexity has where it introduces an arbitrary choice of representation language)?

3.3 Cognition – What algorithms are human brains running that allow humans to learn, remember, model the future, model other minds, reason, plan, theorize, and make inferences? Is it possible to build something broadly as smart as (or much smarter than) a human using just incremental improvements on top of today’s deep learning algorithms (combined with larger data sets and faster computation)?

3.4 Infinities – How should we think about maximizing the expected value of an action in contexts where we can’t assign strictly zero probability to outcomes of infinite value? The mere possibility (i.e. non-zero probability) of an infinite value seems to mess up the calculations completely. If we’re trying to maximize expected value, how do we resolve “pascal’s wager” and “pascal’s mugging” type situations?

3.5 Priors – How can we assign prior probabilities to hypotheses in a principled, computable way (that is, how do we decide what probabilities to assign to hypotheses BEFORE we are given evidence to use to update those prior probabilities)?

3.6 Anthropics – How do we perform reasoning and probabilistic estimation in “anthropic” scenarios where we are forced to consider the probability of even being the sort of mind that could end up in that scenario? What’s the right way to think about questions like “what’s the probability that I would end up being me rather than someone else?” or “what’s the probability that I would end up being a human rather than another species?” or “what’s the probability that I would end up being one of the last 1 billion people to be born before humanity goes extinct?”

3.7 Reference Classes – If we have multiple categories something falls into (each implying that we make different predictions about that things), how do we combine this information into a final prediction? For instance, if ALL we know is that X is a flying car, and flying machines rarely have property Y, yet cars usually have property Y, how do we make a principled “best” estimate of the chance that X has property Y? In other words, what’s the right way to think about combining the information Prob( Y, given A ) with Prob( Y, given B ) when what we really need to know is Prob ( Y, given A and B )?

3.8 Black swans – How do we probabilistically model situations (or do expected value calculations) when we know that “black swan” events (that are unlike any we have seen in the past) are possible, even though we don’t (by definition) know what these events will actually be like and how likely they are to occur?

3.9 Consciousness – Can we be 100% certain that some form of consciousness exists (because we have direct perception of conscious experiences), or should we be less than totally certain even about this?

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4. EXISTENCE

4.1 Many Worlds – Are the “many worlds” of quantum mechanics actually all literally existing (i.e., are they as real as what we all are experiencing right now)? Or does the mathematics just make it seem that way? If they are not really there, what’s the resolution to the “measurement problem” in quantum mechanics (e.g., how do we define what a measurement is and is not such that we have a complete description of when quantum wave functions collapse)?

4.2 Anything – Why does “something” exist, rather than there being nothing at all? Or does this question not even make sense to ask?

4.3 Time – Is there a meaningful sense in which all times that have and will happen exist at once, or do some times only come into existence (as time passes)? Note that the theory of relativity seems to undermine the possibility of a single-speed of time that is the same for all observers.

4.4 Morality – Is there any form of morality that is “objectively” correct? For instance, can moral statements like “murder is always wrong” be true or false in the way that “I once purchased a fedora” is either true or false? If any sort of objective moral truth is possible, what then is objectively true about morality (e.g., utilitarianism, the categorical imperative, virtue ethics, theological ethics, etc.)?

4.5 Non-physical – does anything exist that is not merely made of atoms / not bound by our laws of physics, that can directly cause changes in our world (e.g. souls, ghosts, gods, spirits, the devil, etc.)?

4.6 Time travel – is time travel prevented by the laws of the universe? If it is not prevented by the laws of the universe, has it or will it ever happen? Potentially related: is it possible to exceed the speed of light, or is that literally impossible (as our current theories seem to tell us)?

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5. CONSCIOUSNESS

[Note that, by “consciousness,” I mean the state of having “internal experiences.” A being has consciousness if there is “something that it’s like” to be that being. For instance, there is something that it’s like to be you, but not something that it’s like to be a chair. You have internal experiences, like experiencing the taste of a pineapple or the color of a red apple, but a chair has no experiences. You have consciousness, in the way I’m using the term, but a chair (almost certainly) doesn’t.]

5.1 Justification – Why is there consciousness at all? Couldn’t the universe be just the same as it is now except without any internal experiences at all (i.e., with no consciousness)?

5.2 Requirements – What sort of configurations of matter are necessary to give rise to consciousness? Would it be possible to build a physical device to measure consciousness? If so, what would such a device need to be like?

5.3 Physics – How do we unify the existence of consciousness with the currently known laws of physics (since examining our known laws of physics would not allow you to infer that consciousness experiences even occur)?

5.4 Quantum – Does the human brain exploit quantum physics in a meaningful way, such that it is hard to understand what the brain is doing without using a quantum mechanical explanation?

5.5 Free Will – Why do we have the persistent sense of having free will, even though (given our current understanding of physics) our actions are fully and completely determined by whatever happened a moment before (plus quantum uncertainty)?

5.6 Minimal – Which beings have consciousness? Do atoms? Viruses? Bacteria? Blood cells? Lice? Ladybugs? Spiders? Snails? Frogs? Mice? Beavers? Toucans? What’s the “simplest” possible brain or system or algorithm that can experience consciousness?

5.7 Evolution – Did consciousness come about as a result of evolution (i.e., was it created by selection pressures), and if so, what is its survival function exactly?

5.8 Algorithmic – Is it possible for an algorithm run on a digital computer to experience consciousness?

5.9 Intelligence – Can something be much more intelligent than human beings (broadly speaking) and not have consciousness? Can something behave just like a human in all ways relevant to intelligence and yet not experience consciousness (i.e., can “philosophical zombies” exist?)

5.10 Teleportation – If a teleportation device existed that could make an essentially perfectly accurate copy of you out of new atoms, with all your memories and personality intact, but it destroyed your original self just before assembling the new copy of you, would the copy be you, in the same sense that you one second from now is still you?

5.11 Macro – Is it possible (even if extraordinary difficult) for a large-scale, purely mechanical system to have consciousness, for instance, a massive machine made out of gears and pulleys? Could a very large number of people, if they were all carrying out coordinated movements that were designed to match the algorithmic information processing of a brain, temporarily create a large-scale consciousness?

5.12 Agent – What’s the right definition to use for a single “being” or “agent” that properly distinguishes it from all other beings, while still handling even weird thought experiments. (For instance, where a person’s brain is split into two but continues to operate, or where a brain is slowly replaced with pieces of another brain over a long period of time, without ever ceasing operation)?

5.13 Finality – Does all experience cease after death, as atheists typically believe and as spiritual and religious people typically deny?

I’ve included the details of the event format below, including materials you can use to throw your own version of it.

Important Note: this event format requires at least ten attendees to show up (I recommend at least five males and five females) so as to avoid de-anonymizing participants. When I ran it there was about 20 people, which is close to ideal, I think.

GOALS

The goals of this event are:

• to help attendees understand each other on a deeper level (including potentially gaining some insight into human nature in general)

• to enable attendees to see how their thoughts, feelings, and behaviors are similar or different to those around them on topics that typically are taboo to discuss

• to have an interesting and enjoyable time.

I got a very positive response to this event format from those who attended.

THE FORMAT IN BRIEF

• Attendees will be asked to completely honestly fill out an anonymous survey at a minimum of 24 hours before coming to the event, which will contain many controversial, taboo, embarrassing, uncomfortable, and rarely asked questions.
• You’ll then compile the responses (grouping them by question in a totally anonymous way and calculating the % of people that gave each response for multiple-choice questions).

• You’ll hand out printed versions of these responses to attendees when they arrive. After the attendees have time to read through all the responses, you’ll then go question by question, having a quick group discussion about the responses to each.

• At the end, you’ll discuss as a group what you all learned from the experience.

• Finally, you’ll collect the sheets from everyone and shred them so that no one has a record of people’s private responses.

HOW TO DO IT

Step 1: Make a copy of my online survey containing taboo, controversial, and rarely asked questions (using the survey of questions I already created is the easiest option – preview all the questions here: http://bit.ly/2o5GBjq, and make a copy of the survey here: http://bit.ly/2Cm9oVH so that you can send it out). Or, if you have more time and want to customize the questions, you can crowdsource them from attendees in advance and put them on a survey platform that doesn’t record any personally identifying information (i.e., no email address, no IP address). If you plan to crowdsource questions, you should send out an anonymous survey to attendees beforehand to ask what questions they would want to be answered by other attendees (anonymously) that they would never normally be able to ask (here is my survey for collecting these questions from attendees: http://bit.ly/2BYQDvM and you can make your own copy of this survey here: http://bit.ly/2EqVszY). Once you get the questions back, you’ll turn them into another anonymous survey (where you actually ask those questions) which you will also send out to attendees before the event (being sure to give yourself plenty of time to process the responses to prepare event materials).

Step 2: Send an invite to potential attendees (sample invitation down below), including a detailed explanation of the event format (so they can knowingly opt-in rather than having it sprung on them). If you have the survey questions already, you should include them in the invite as well. Make sure to make it clear what the deadline is for fill out the survey (I recommend setting it to be at least 24 hours before the event starts so that you have time to prepare the results). Be sure to send a reminder before this deadline to increase the percent those who respond.

HOW I CONSTRUCTED THE QUESTIONS

I constructed my set of “taboo, controversial and rarely asked” questions (available at my survey link above) using the following process:

A. I crowdsourced question ideas from all the people who planned to attend the event.

B. I brainstormed additional ideas on my own that seemed like they could be interesting.

C. I then ran a study where 100 people in the U.S. on the Amazon Mechanical Turk recruitment platform were asked to answer each question anonymously. I ended up with way too many questions for the final survey.

D. I winnowed them down by reading all the responses of people on Mechanical Turk, retaining for the final survey those questions that seemed to me to produce especially interesting or surprising or discussion-worthy results (see link below for anonymous Mechanical Turk user responses if you’re interested).

PREPARING FOR THE EVENT

After you’ve received everyone’s survey responses, you’ll want to prepare handouts for each participant with all of those responses in completely anonymized form. It is critical that you never read any one individuals responses while you’re preparing the materials. Group the responses immediately by the question, and shuffle their order, so that you can only ever see the responses for all respondents as a group. This helps ensure the anonymity of every respondent. For multiple-choice questions, you should calculate the percent of people that gave each response (I put these on PowerPoint slides which I presented to the group, but you could put them right on the handouts). For free form text responses, you’ll want to have a list of all responses to each question, grouped by question. Be sure to shuffle the order so that the 1st response to each question is not the same person each time (otherwise, participants may accidentally be de-anonymized).

If you use the exact questions that I did, you can also show alongside your group’s responses, the responses from Mechanical Turk respondents, which you can find here in the anonymized form: http://bit.ly/2HgzX2s. I recommend only doing this for the multiple-choice questions, as otherwise, the handouts might become unreasonably long (expect to give at least seven pages of handouts if you have 20 attendees and you use a small font and are smart about space on the page).

OPTIONAL: USING MY PYTHON CODE TO PROCESS RESPONSES

If you use my exact survey, you can also use python code (download it here: http://bit.ly/2Hgi6su) that I wrote to make the process of preparing responses easier and prettier (you’ll need to use Python 2.7 to use it, which you can easily install on Mac or PC). You’ll also need to install the pylab and text wrap libraries (first install pip, which is a python installation system, then you can easily install these using pip). The way the code works is that it takes two input files: one has the responses from mechanical Turk workers (which is already provided for you in the folder you download, so there is nothing for you to do), and the other is the CSV file you download yourself of your attendees’ responses to the survey (you can get to this download option from the edit page for your copy of my survey, just click on data and you’ll see a download button). Place that CSV file you downloaded into the “python code” folder once you unzip the code (usually, you can unzip just by double-clicking). Then change the line of code comparisonFileToProcess=”…” within the file prettyPlotYesNo.py so that the … is replaced with the name of your CSV file. Finally, run the python file prettyPlotYesNo.py by navigating to that folder in terminal (Mac) or Cygwin (Windows) and doing:

python prettyPlotYesNo.py

It should then automatically fill the folder “figures” with all the results (including both figures and text files of qualitative responses). The skinny bars will represent the responses of mechanical Turk workers, and the thick bars will represent the responses of your attendees, so you can compare them side by side (i.e., you can see how representative your attendees’ responses were).

AT THE EVENT

Hand out printed sheets that show the responses of all the attendees to each of the questions. Give people 10 minutes or so to read them all (to form initial impressions and reactions). You may want to provide pens so that people can jot down notes as they go or mark responses that were especially interesting. When people are done, start with the first question, have everyone quickly read the responses to that single question again to remind themselves what others said (if it was a qualitative question) or have them look at the percent of people that gave each response (if it was a quantitative question), and then have a short group discussion about the responses to that question. If people are quiet, you may want to ask the room questions like:

•What was your reaction to reading people’s responses to this question?

•What surprised you about the way people answered the question?

•What patterns did you notice in people’s responses?

After a few minutes, or if people no longer seem to be engaged in the discussion, or if the discussion has gone on a tangent, move onto the next question (having everyone quickly read the responses to that next question again before discussion ensues). Repeat this until you’ve gotten through all the questions.

At the end, ask people what they feel like they learned overall from the experience of seeing attendees answers to these questions and discussing them as a group. When we ran this, people had a very positive reaction to the experience!

Be sure to collect all the handout materials back at the end and shred them. Make sure everyone knows at the beginning that they will not get to keep the sheets of people’s responses and that they should hand them back to you before leaving to protect the private responses of all attendees.

SAMPLE INVITATION TO SEND FOR THE EVENT

I’d like to invite you to an event called “Anonymous Answers to Anonymous Questions,” where you’ll get to find out the (anonymous) answers that all the other attendees have to controversial, taboo, embarrassing, uncomfortable, and rarely asked questions.

Here’s how the format works in detail. Please read these instructions carefully if you plan to attend, and let me know that you’ll be coming!

Before coming, all attendees will fill out an anonymous survey (see link below) with a bunch of controversial, taboo, or otherwise unusual questions. At the beginning of the survey, you and the other attendees will be asked to swear that you will respond completely honestly.

When you arrive at the event, you’ll get to see all the responses given by other attendees to all the questions (in a completely anonymized format). We’ll then go question by question, reviewing them together, and discuss them as a group (without knowing who gave which answer)! You will not be able to take any materials with you when they leave because they will contain the personal responses of group members.