superposeur

These decades, whenever the word "Wolfram" comes up, reliably discussion will center on his tone and style. My advice: don't confuse the message with the messenger.

Mathematica (yes even I can't bring myself to call it "Wolfram Language" or whatever) is an exquisite and indispensable software system, a true aid to thought. Likewise for Wolfram Alpha.

(And yes, agree his cellular automata stuff is unconvincing.)

Me too. The last portion felt rushed and hollow. The metaphor of “holding the hand of the black man to help him vote” is problematic along several axes. On the other hand, still wicked good account of the Kennedy brothers and Hoover.

Agree that 3 is great. My favorite is 1, which is next-level even by the high Caro standard: moving to the hill country? Finding un-censored copies of LBJ's yearbook? Unearthing his affair with Alice Glass and the tales of family conflict from his brother? The manic ambition of his first Congressional race as related by his driver? The secret, crucial influence of Brown&Root? -- WTF, no other writer in a thousand years could have written that book. Also, I'll put in a plug for 2, which in my opinion is sorely underrated.

The high point of my reading life was listening to the audio Caro books. In a book review, George Will somewhat derogatorily called the Caro style "incantatory", with Caro's relentless repetition of metaphors such as the "dam" of Southern Democrats holding back Civil Rights, and phrases such as the "three R's" of Roosevelt, Rayburn, Russell. But it is this incantatory style that makes the writing spring to life in audio. And, yes, you can make your way through them while doing laundry or driving to work.

Completely agree, there is a "texture" to Caro missing from all other biographies I've read (indeed, almost all other books). At once more vivid, detailed, complex, and rich, with first-hand access to new sources and interviews (something a biographer of a long-dead figure could never achieve). You feel as though you are getting the real scoop even for subjects you thought you understood.

After reading Caro, I'm left with the sad impression that there is probably a more vivid layer to most historical events at odds with the "cartoon" layer that has been passed down, but which we will never know because the singular figure of Caro was not there to chronicle it.

I read the interview expecting exactly what you describe. Instead I found a nuanced and illuminating discussion —- at least for a non-expert such as myself. Marcus references the symbolic vs connectionist debate and (at least by his own description) seems to be what you call a “bridger” of long standing.

His objections seem concrete and well supported — not just repeating “but does it really understand” over and over. (Admittedly there is some of this.)

Edit - Thank you for the links.

This reads to me as a cogent defense of one particular interpretation: Everett.

All is clear and logical except the part where Aaronson endorses the opinion that Everett isn’t wrong, but grandiose (whatever this means). In justification, it seems he is pushed into further twisted locutions. He speaks of what “breathes fire” into branches of the wave function and says that the question of existence of other branches is “above the pay grade of physics”. Breathing fire and pay grade of physics?

How much simpler to just assert that yes evolution is unitary at all times and, yes, this implies many classical branches.

To add to this, the states robust to entanglement with environment were dubbed “pointer states” by Zurek since they are the quantum states most closely analogous to the “pointer” of a measuring apparatus showing one particular result.

This is my thought as well.

Good point -- counting all the stars in the observable universe is already a big overestimate of the ones that could support life.

Here is a plausible alternative scenario. As planets form, there is a certain window of opportunity where conditions are right for life to get going (among other extraordinarily unlikely accidents that must come together, the phase of planetary evolution must be just right). Almost always, this too fails. After all, every attempt to date to recreate primordial conditions in the laboratory have failed to produce any life.

I return to the key point: the number of planetary systems in our observable universe is not infinite. It is not much larger than atoms in a macroscopic chunk of matter. It is entirely possible that the probability of life forming on a given planet is much too small for it to have happened in the last 13.7 billion years. This is just like the fact that the probability of radioactive decay of an atom (even in a sizable sample) becomes unlikely if the half-life is too long compared with the time scale of observation.

I fear that "much close to 100%. There just has to be" (as much as I too would like to share in this sentiment) may be an anthropomorphic projection and wishful thinking. Anthropomorphic because we are living creatures and assume that there must be other living creatures in the region of the universe we can see, even if just biochemically.

But, one thing we are able to estimate is the number of stars in the observable universe -- that collection of stars in causal contact with us. It is far from infinite. In fact, not that much larger than the number of atoms in a macroscopic chunk of matter. The number of possible games of chess is incomparably vaster.

If by "universe" we mean everything out beyond our causal horizon in an infinite universe, then I would guess that yes, there is other life. Actually, there are other copies of you too, because everything that can happen does happen in an infinite universe. The hinge of my point is that the observable universe is not infinite.

This is not to say, by the way, that we should not continue looking for traces of life or to be open to these.

Ok, so you are setting the scale as "from the present conversation back to formation of Earth" and saying that this is large in comparison to "from formation of Earth to formation of RNA". However, I respectfully don't see how this scale has any bearing on the probability of life forming around another system. Formation of life is certainly a prerequisite to the formation of intelligent life (the two events in question). Both could have a probability of occurring much smaller than 10^-24 (approximate # of finite stars in observable universe).

Yes, we know little (aside from the finiteness of the observable universe, which is known at a quantitative level). I am curious why then you say "so far, we're pretty sure there is some life in the universe, but nothing else." I fear this may be anthropomorphic projection and wishful thinking.

Yes, these are alternative explanations. The explanation that is surprisingly undermentioned is the one I put forward: there is no life.

Yes, I would then think it's probable to be many places (and would be very happy about this as I would not like to be alone in the cosmos).

"Short period" and "right off the bat" are terms without meaning. What sets the scale of "short"?

True that we know little and actually this is my point. I fear that "of course there is life out there in the universe" (as much as I too would like to share in this sentiment) may be an anthropomorphic projection and wishful thinking.

One thing we are able to estimate is the number of stars in the observable universe -- that collection of stars in causal contact with us. It is far from infinite. In fact, not that much larger than the number of atoms in a macroscopic chunk of matter. The number of possible games of chess is incomparably vaster.

This is not to say that we should not look for traces of life. That is a completely separate question.

In my opinion, the excitement occasioned by the discovery of so many exoplanets has clouded our collective judgement on the Fermi Paradox, leading the overwhelmingly most probable resolution to be underemphasized.

Namely: there is no life out there. Not due to baroque mechanisms such as techno-self-destruction but just due to its sheer unlikeliness. As large as the number of stars in the observable universe is (let’s say 10^24?), the space of combinatoric possibilities that must be threaded for the sustained chain reaction of life to occur is probably that much vaster. The so-called Drake equation is not useful since multiple terms have error bars that are not even estimable.

Thanks for this suggestion. I couldn’t believe the quality of the Rhodes book.

Agreed that this is low probability. But it did strike me that the Nazi brass were most interested in such a crash program, at one point declaring that it should be given top priority. What dissuaded them were the apparent failures of early efforts and lack of confidence of the scientists themselves — the scientists got hung up on use of heavy water as a neutron moderator, among other suboptimal practical decisions.

Having just finished the epic Making of the Atomic Bomb by Richard Rhodes, my mind goes to a different place —- Heisenberg was at the core of the German bomb project. Speculatively, I wonder how things might have gone a different way had he been required to be a brilliant experimentalist too. Success versus failure hinged on nitty-gritty experimental details, not on sweeping theoretical insight.

Probably not, but then again — Germany is where fission was discovered and an also a powerhouse of chemical engineering. Not all of German science fled the nazis.

It strikes me that many people have pet theories to the effect of: “if only the idiots teaching did it _this_ way, the problem of pedagogy would be solved”.

In other fields, non-experts recognize that the business is subtle, involves trade offs, and if you haven’t ever done the thing maybe you should be careful about presuming to know the best way to do it.

I think it’s because everyone has been a bored student in a class at some point so feels entitled to an opinion, although few have actually taught a class or truly weighed all the considerations in doing so.

I’ve heard it said that the angular size of many astronomical targets is not so small — that the real limit to seeing them is the overall amount of light collected.

But then some basic sense of scale eludes me: 1) isn’t most astronomical stuff insanely far away, to the point that it would have to be cosmically large to take up a medium angular size? 2) the angular “real estate” in the sky is severely limited (4pi solid angle) so wouldn’t this get quickly used up such that we could only see a small collection of such objects? (Andromeda is already taking up a huge patch of the night sky!)

Of course these are quantitative questions that can be settled by calculation, but does anyone have relevant intuition to offer?

Agreed — superdeterminism is not so much a theory as a theory-for-a-theory at this stage (a vague guess at the form such a theory might take).

It is a sign of the much greater maturity of the physical collapse models that their parameters can be constrained by experiment. The ability to be constrained is a good sign, not a bad one.

I love John Preskill’s standard nod to superdeterminism in his writings: without mentioning it by name he says “I leave it up to the reader to decide how seriously to take this possibility” (get it?)

This is a great list. To the point that if you have any other book recs lying around (not necessarily sf, not necessarily last 5 years), I’d love to hear!

As I read the post, she takes the fact of a Hot Big Bang (narrowly construed in the modern sense of a homogenous, hot initial state prior to which vanilla GR breaks down, not as a literal singularity) to be a fact knowable by the normal process of science. Whereas the question of what came before that — I.e. what modified description takes over at higher temperatures yet — is placed in a different epistemic category of forever unknowability.

Of course, for any theory that applies within a certain domain, there’s always the question of what happens beyond that domain (“what came before that… and before that… and before that…?”). But this infinite regress isn’t particularly noteworthy. If I understand her correctly, she is claiming to be able to draw a particular line and to say that we can know things on one side of this line but— even in principle — can never know anything past this particular line.

She certainly understands her stuff. But I respectfully disagree with her conclusions — I see no reason to think that we might not make progress on the question through the normal process of science.

Yes, but this is a generic rubric to apply to all frontiers of science: falsifiable theories are good; unfalsifiable theories are bad; even when you falsify a theory, there will always be room to fudge and rescue it by making it more baroque; the principle of parsimony should be applied to give less credence to baroque theories.

I see no reason to place the frontier of "what happened right at / before the Big Bang where vanilla GR breaks down" in a different epistemic category than all other frontiers of science, as the blog post seems to do. i.e., I see no reason that we should not build models and collect data in order to expand into this frontier, as we profitably do in other areas of science.

I’m a big fan of the blog, but disagree with this entry. Her argument could be applied to the idea of the Big Bang itself: we can never receive light from any further back than the “surface of last scattering”, so the notion of a hotter prior epoch is an extrapolation. The extrapolation is a good one as it uses independently-tested laws of evolution, at least to the point these laws presumably break down, as she points out.

Similarly, it’s entirely conceivable that we may find independent ways to test which of the proposed modifications of the evolution laws is correct, for instance by using data collected from binary mergers. Then, these modified laws would lead to a modified story of what happened near the Big Bang. Alternatively, it may happen that all but one or a few of the proposed modifications do not play nicely with the other forces of nature at a theoretical level.

Or maybe not, but we certainly can’t rule out this possibility a priori.

Moreover, her point about not having a multi-universe data set would dismiss all of cosmology as mere “ascience” — again, including the notion of the Big Bang itself.

Instead, I think it likely that the present multiplicity of early universe proposals will be pruned as more data becomes available.

True that, but from the point of view of an outside observer, their wavefunction does have a phase that regularly oscillates (with a frequency corresponding to the color of the photon)