"Claims that the standard procedure for testing scientific theories is inapplicable to Everettian quantum theory, and hence that the theory is untestable, are due to misconceptions about probability and about the logic of experimental testing. Refuting those claims by correcting those misconceptions leads to an improved theory of scientific methodology (based on Popper's) and testing, which allows various simplifications, notably the elimination of everything probabilistic from the methodology (‘Bayesian’ credences) and from fundamental physics (stochastic processes)." – David Deutsch
Popper's criterion in a vacuum could seem to be exclusionary, but his philosophy of science involves his underrated idea of evolutionary epistemology. That all theories, seemingly pseudoscientific and the rest, compete to explain something, testable or not. Explanation is the most fundamental aspect, the rival statements compete to solve some problem in terms of how and why.
I didn't think of nuclear subs. It would seem ideal for running a small moonbase. But I don't know how self-contained those reactors are, or how much they weigh. Surely a lot.
There are also the nuclear batteries in some of the longer lived space probes. Those batteries have the major advantage of being very simple - a lump of radioactive material that gets warm - attach a thermocouple and voila! Electricity!
LFTRs can scale down to closet sized, and most of the fuel (Thorium) is stable aside from the ignition uranium plug, but there's a LOT of materials to solve for long service.
There are no resource limits, only limits to the creativity of people to create explanations that allow us to transform raw materials from one state to another.
See The Beginning of Infinity by Deutsch and More From Less by McAfee.
This is false. There are resource limits, unfortunately (I guess?). Thermodynamics is a hard limit. There are many soft limits as well. Please look at this paper for an incredibly well researched physics-based review: (to appear in Nature Physics) https://tmurphy.physics.ucsd.edu/papers/limits-econ-final.pd...
> At present,
the waste heat term is about four orders
of magnitude smaller than the solar term.
But at a growth factor of ten per century,
they would reach parity in roughly 400
years. Indeed, the surface temperature
of Earth would reach the boiling point
of water (373 K) in just over 400 years
under this relentless prescription. Clearly,
extrapolating our recent — seemingly
modest — 2.3% annual energy growth
very far into the future quickly becomes
ridiculous, and cannot happen.
> This is not intended to suggest that
waste heat is a bigger problem than, say,
climate change from carbon dioxide
emissions (...)
Exponentials can get away from you a lot faster than you might expect. For instance if we sustained a 1% annual population growth for another 13000 years the total volume of all living people would be more than the total volume of all the space within 13000 light years of Earth.
So unless we get faster than light travel or we greatly reduce the amount of space into which you can physically cram a living human we are under 13000 years away from a pretty hard upper limit.
Make more realistic assumptions than speed of light expansion of humanity and that limit gets a lot shorter even with growth rates quite a bit lower than 1%.
> if we sustained a 1% annual population growth for another 13000 years
And if we sustained a 0.03% annual population reduction rate (like South Korea recently experienced) there would be less than 100 people on Earth after just 600 years.
So I agree that exponentials can get away from you a lot faster than you might expect, but I also think that trying to predict cultural norms 13 millennia from now is likely to be counter-productive.
Per the article, actually about 100-1000 times beyond current capacities.
In a way I agree that the feasible limits, even on Earth, may be orders of magnitude larger (say, in terms of population, perhaps) than we currently have. But the current rate of growth in any case is probably unsustainable because of imbalances like co2 emissions. I do think it's feasible to change to renewable energy in the short term, if only political motivation was a bit higher (please, go out and vote focused on climate change, folks!). If I were to lay out a strategy for humankind, I'd say we should focus on climate change for the next few decades, and then we can resume growing (to avoid possible collapse).
Limits to technology are actually non-trivial due to the atomic nature of objects, limited number of chemical elements with limited range of properties, etc.. Intelligence itself isn't free and keeping the Great Self-sustaining Rube Goldberg contraption working is not trivial. It's very hard to predict what limitations we can overcome -- see Moore's law slowing down. Some limits we've almost reached such as luminous efficacy (LEDs in lm/W). Soon we'll be faced with the question of whether we want to make Earth into a Caves of Steel landscape (ending most natural life to create a hyper-efficient human/machine habitat) capable of sustaining more humans or a Solarpunk landscape (preserving natural ecosystems) with a more limited population. I think there's a large degree of arrogance to the first, because I don't feel competent enough to evaluate the true value of animal lives, supposing a large quantity of animals are sentient, and they have intrinsic scientific and cultural value. I think this requires an exercise in imagination from all of us. In any case, it's probably a great idea if we could at least keep the oceans, rainforests, and major national parks healthy.
One crazy dream I have is to colonize not Mars, but Mercury. In Mercury solar energy density is crazy high. There's even some thermal energy from the solar thermal gradient. You can dig to get to nice temperature ranges and be safe from radiation, all this works well since the planet is tidally locked and therefore doesn't rotate, there's no diurnal variation. You can build a crazy Cave-of-Steel there and live your life in a cramped cell playing video games (or [insert activity]), if that's what your vision of heaven is.
Diamond-based molecular nanotechnology, combined with fusion and high efficiency solar as sources of power will make all of our technology and infrastructure carbon sinks. By the end of this century I expect we will be concerned about CO2 going too low and causing a glacial period.
PS Mercury is too far in-system to be that useful. It takes less energy to get to/from the outer planets than it does Mercury. The cold traps on the poles are interesting though--mercury potentially has all the raw material needed for a self-sufficient industrial colony.
You have suggested in the same comment that somehow we will have nearly limitless carbon-negative energy but also that the amount of energy to get to Mercury is too high to make the trip worth it. This does not follow from the initial assumption.
A lot more Mercury than sum of all asteroids. On the scale of "this century" this may only matter for von Neumann probes building a Dyson swarm, but that's not a 0% possibility and you did ask for a reason.
Eh, if it's economical to have the sinks at that scale, we probably won't turn them off for the same reason we "could" turn the CO2 sources off but don't.
The ideal setup is probably CO2 levels quite a bit higher than today’s, but with a sunshade filtering out UV-B wavelengths. All of earth would be habitable, but without major weather swings.
Higher CO2 levels will result in vastly more arable land, mostly from the reduction of deserts and the warming of permafrost. Higher CO2 levels make agricultural crops grow faster and bigger. Higher CO2 levels (within the range I was talking about) has no effect on human respiration. Ideal for plants is good for us too.
"They found that if the outdoor CO2 concentrations do rise to 930 ppm, that would nudge the indoor concentrations to a harmful 1,400 ppm.
…
In fact, at 1,400 ppm, CO2 concentrations may decrease basic decision-making ability by 25%, and complex strategic thinking by around 50%, the authors found."
Ok I didn't mean to imply maximally ideal. 300-400ppm CO2 would be a tremendous boon to both agriculture and most biodiverse wild ecosystems (e.g. jungles & forest tundra, not deserts). It would also warm polar regions more than it does equatorial regions, making northern Alaska, Canada, Russia, and Scandinavia more tolerable to large-scale, year-round human habitation, as well as Antarctica and Greenland (the resulting sea level rise being an issue tho).
Of course if you assume continued exponential growth you will run into limits. The correct response to that is to not assume continued exponential growth indefinitely, since in the real world that never happens.
In actual real world systems, the growth curve is sigmoidal: it starts out with exponential growth, becomes linear, then asymptotically flattens as system constraints are approached. This is already happening with human population, and should be expected to start happening with other resource curves in the fairly near term. Any properly grounded analysis would look at the situation from this point of view.
The exponential growth of neutron flux in a detonating nuke may be overwhelmed by a different function as the pieces fly apart, but I wouldn't want to be part of that even allowing for it being a metaphor.
wrong. As system constraints are reached, growth becomes negative. In other words, you need a steady supply of resources just to maintain existing stuff.
No, you don't, because "resources" don't magically vanish once you've used them. They just become harder to extract (assuming they're not already being renewed--in the biosphere, "resources" are constantly being renewed by biological processes); but that's what technology is for. For example, it is said that we are using up fossil fuels; but combustion processes don't need "fossil fuels" specifically, they just need easily transportable liquid fuels with decent chemical energy content, and we can make those, because the atoms that the fuels are made of are still there; they didn't vanish when we burned the fuel. We don't do that now because it's cheaper to use fossil fuels while we have them; but of course that will change as fossil fuels run out.
Similar remarks apply to just about anything we currently call "waste"; sooner or later, if we need to, we will find ways to recycle all of that "waste" into something usable. The key limitation is population growth, but as I've already said, population growth is already into the "asymptotically flattening" phase.
It's possible, of course, that population growth will in fact go negative (many projections assume that); but that doesn't mean it will stay that way. The exact sigmoid curve is obviously an idealization; real world systems do oscillate about reasonable equilibrium points instead of just staying stuck at them.
I think the parent post means that resources are strictly speaking improved goods not raw materials. I’m that sense innovation and thermodynamics are the limitations, not what rocks we pull out of the ground.
Yes, therefore limits. At least in the short and medium term (which could be 1000s of years). Look at the technological advancement of Roman empire, lost for a millennium before human ingenuity advanced past that level again.
Good video from Jonathan Blow on rise of complexity leading to collapse and lost knowledge [0]. Add in energy and resource constraints (for the given world popuplation numbers) and we may be in for a bad time for a while in the near future.
For the clearest and most precise view of Deutsch's philosophy of science in the context of quantum theory, read his paper The logic of experimental tests, particularly of Everettian quantum theory: https://www.sciencedirect.com/science/article/pii/S135521981...
Prevailing discussions (e.g. Dawid & Thébault, 2014; Greaves & Myrvold, 2010) of the testability of various versions of quantum theory have approached the matter indirectly, in terms of support or confirmation – asking how our credence (degree of belief) for a theory should be changed by experiencing results of experiments. However, experimental confirmation is a philosophically contentious concept. Notably, it is rejected root and branch by Popper (1959). I shall present an account of the nature and methodology of scientific testing that closely follows Popper׳s. It differs from his, if at all,3 by regarding fundamental science as exclusively explanatory. That is to say, I take a scientific theory to be a conjectured explanation4 (explanatory theory) of some aspects of the physical world – the explicanda of the theory – that is testable (I shall elaborate what that means below) by observation and experiment. A scientific explanation is a statement of what is there in reality, and how it behaves and how that accounts for the explicanda. Neither confirmation nor credence nor ‘inductive reasoning’ (from observations to theories or to justifications of theories as true or probable) appear in this account. So in this view the problem described in Section 1 is about testing theories.
This contradicts the ‘Bayesian’ philosophy that rational credences obey the probability calculus and that science is a process of finding theories with high rational credences, given the observations. It also contradicts, for instance, instrumentalism and positivism, which identify a scientific theory with its predictions of the results of experiments, not with its explanations. My argument here, that Everettian quantum theory is testable, depends on regarding it as an explanatory theory, and on adopting an improved notion of experimental testing that takes account of that.
Scientific methodology, in this conception, is not about anyone׳s beliefs or disbeliefs. Rather, it assumes that someone has conjectured explanatory theories (though it says nothing about how to do that), and it requires those who know (i.e. are aware of) those theories and want to improve them, to attempt to locate specific flaws and deficiencies and to attempt to correct those by conjecturing new theories or modifications to existing theories. Explicanda in the sciences usually involve appearances of some sort (e.g. the perceived blueness of the sky). Theoretical matters can also be explicanda (e.g. that classical gravity and electrostatics both have an inverse-square force law), but those will not concern us here. Explanations of appearances typically account for them in terms of an unperceived, underlying reality (e.g. differential scattering of photons of different energies) that brings about those appearances (though not only them).
I believe you can actually get Popperian falsification out of Bayesianism if you squint right. Consider an falsification experiment. It disproves some theories while not changing our relative beliefs in other theories.
this would be basically
for all i in S1 p(evidence | theory i) = 0
for all i in S2 p(evidence | theory i) = k * p(evidence)
I would say that most scientific evidence is of this sort, except that the probabilities for the "falsified" theories can also be a little bit above 0 to account for measurement error.
Edit: Actually it may be fruitful to introduce a distinction similar to the one probability theory has... In probability theory there is a difference between sample and event. An event is a set of samples. In our case, I believe we want a distinction between a theory... and a lets call it micro-theory. To pick a funny and memorable example a theory could be something like "there is a Loch Ness monster". Now a micro-theory could be something like "there is a Loch Ness monster, that is invisble, and makes no sounds, but it can be detected by radar... and... and...". So it would include all these additional constraints. So the theory it's composed of a lot of these micro theories right. Now if we take photos of every inch of Loch Ness, and we don't find any Loch Ness monster, we make it less likely that there is a monster right. We may say "oh we were careless, and just missed it" but if we keep looking eventually that becomes an impossibility. So we disprove a bunch of micro theories, but some will remain. Our previous micro theory that among other thing says that the monster is invisible remains. And whats worse the relative likelyhood of them is unchanged compared to the no monster.
p(cant get monster on photo | no monster) = k p (cant get monster on photo) and
p(cant get monster on photo | invisible monster) = k p (cant get monster on photo)
Now if we want to further increase our belief in "no monster" we would have to go after these wacky micro-theories and disprove them, using e.g. radar. But given that a sensible person assigns those micro-theories low prior likelyhood we may be satisfied with the situation and not bother.
So basically these was just Popperianism in Bayesianism clothing right? Almost... Notice the very last point. We allowed ourselves not to bother with theories of invisible monsters. Because of our prior likelyhood.
It's amazing work. Building from his work around The Beginning of Infinity, and The Fabric of Reality (1997), which Naval has been doing a podcast on: https://nav.al/agi
Because most school is forced knowledge work on problems that don't fit the person's problem situation.
When people are free, they learn the math they need for the problems they are trying to solve.
Traditional, compulsory school forces children to solve problems they don't have. See Karl Popper's idea of the bucket theory of mind, or David Deutsch and Taking Children Seriously.
> most school is forced knowledge work on problems that don't fit the person's problem situation.
Have you never been in a situation where you are about to take train going at 80 mph; wondering when you'll meet up with your friends going in the opposite direction at 90 mph?
I recently saw a great photo [1] by Ben Cooper of a Falcon 9 on ascent crossing the Moon from the photographer’s perspective. I wonder how much math went into finding that vantage point.
It's not really that hard. I set up several systems to do this for the previous total solar eclipse. The ephemerides for the moon are easy to download and calculate the position in the sky (IE, altitude and azimuth at time t) with a python script.
I believe also the launch vehicle has a launch window (the moon moves 15 degrees per hour) and launch trajectory. I'm lazy so I'd compute the extends of the launch vehicle's motion in the sky (from earliest possible launch to latest possible launch), and then intersect that geometry with the moon position geometry without explictly trying to solve the equations simultaneously. That should back-project to shapes on the ground at which point you could reasonably expect to be able to get a good shot, and then you'd do some adjustment in your pointing in real time.
A smart college senior could do it directly (IE, not lazily compute a bunch of points and manually intersect them on a screen).
Having done a lot of long road trips, I have often entertained my tired brain by trying to calculate how long it will take me to get to mile marker x, or city y (SPRINGFIELD 400 says the sign) based on how fast I'm going, then how long it would take if I was going 1mph faster or slower, or 5mph, etc. It's relatively simple but to do so entirely mentally seems to take a lot longer for me than I if I could just jot a few notes down. It gets more fun if you try to account for how long it takes for you to slow down for an exit, take a piss and get a snack, then get back up to speed.
I didn't know, for the longest time, what a derivative was. I still don't, not really, though I can bluff my way to a reasonably correct answer using the above analogy and going from dry "rate of rate of change" sort of language into more practical concepts.
Yeah really, when I finally found a reason to get interested in higher level math, I then realized it built on much knowledge from my 12 years of school that I neglected to care about to learn, all further down the chain of abstraction and further away from my problem to the point where it’s no longer interesting again.
pdf, The Logic of Experimental Tests, Particularly of Everettian Quantum Theory https://www.sciencedirect.com/science/article/pii/S135521981...