blix

Nature is asking for a subscription, so here's a version on arxiv: https://arxiv.org/ftp/arxiv/papers/2103/2103.13925.pdf

Probably not. Steel rebar is used because it is ductile, that is it stretches and fails gracefully, which complements the brittle nature of concrete.

This material is likely brittle, probably similar in overall behavior to graphite.

It's hard to say without reading the paper itself, but in general one should be skeptical of claims that such-and-such material is stronger than steel. The properties that make steel interesting are not its elastic modulus or yield strength.

This material is probably closer to graphite (which beats steel in elastic modulus and yeild strength) than something you would actually want to use in a structural application. It will probably be ~very~ difficult to print.

The interesting thing about trust is it takes much longer to build than to spend.

Given the level scientific institutions have been spending trust over the past few years I'm not sure how this problem can be alleviated within our current framework.

Thanks for confirming my take. This is a little out of my comfort zone.

Do you see a future for this simulation method with increased computing power, or do you think limitations of the method might still limit its applicability. Maybe this is naivete coming from atomistic perspective, but it seems to me that the inability to model reactions that aren't explicitly predefined would be a significant challenge.

I am not an expert on this type of model but after reading their methods section a little more thoroughly, this is my sense:

I don't believe there is any case where a molecule in one voxel knows about molecules in other voxels. DNA and RNA is coarse grained where a 'molecule' might represent a specific sequence of interest rather than a full chain. Transcription and translation are modeled, essentially by saying if the neccessary ingredients are present in a voxel (DNA/RNA sequences, enzymes, raw materials, etc) there is some chance of forming mRNA or a protein as a function of the molecular concentrations present in the voxel. DNA and RNA reactions are treated with somewhat different equations than the rest of the molecules, I think to handle the coarse graining.

I guess it's just wierd to me to see ab initio used to describe a class of methods than in my field it explicitly precludes.

Having developed a few newtonian force fields, calling them "derived from QM" is very, very generous :P

> It does represent that many atoms.

It also represents even more electrons and even more quarks than that. I think it would be silly to characterize this system by the number of constituent quarks, but that's just me. To me, the important number is the number of degrees of freedom within the model. In a force-field model this scales linearly in with the number of atoms. In the model presented in the paper, this depends on voxel resolution and number of molecular species. Sadly, this is omitted in the press release.

Thanks for your links :) I work in inorganic materials but I really should understand more about models for more complex systems.

I would not describe AMBER, or anything using a newtonian force field, as ab initio.

In inorganic materials ab initio means you actually solve Schrodinger's equation (though obviously with aggressive simplifications e.g. Hartree-Fock).

I do classical molecular dynamics simulations for a living, and I feel the model using in this paper is pretty dramatically different than what would typically be described as classical dynamics. 2B atoms would be absolutely insane for any sort of simulation that resolves forces between atoms of even groups of atoms, especially in organic systems.

As far as I can tell from their model, molecules don't interact with each other ~at all~ through classical dynamics. Rather, they define concentrations of various molecules on a voxel grid, assign diffusion coffecients for molecules and define reaction rates between each pair of molecules. Within each voxel, concentrations are assumed constant and evolve through a stochastic Monte-Carlo type simulation. Diffusion is solved as a system of ODEs.

This is a cool large scale simulation using this method, but this is a far cry from an actual atomic-level simulation of a cell, even using the crude approximations of classical molecular dynamics. IMO it is kind of disingenuous for them to say 2B atoms simulation when atoms don't really exist in their model, but it's a press release so it should be expected.

The most recent doctor I asked was 6 months ago. I've been diagnosed with Chrons specifically, so that may be a factor.

Incidentally, my current diet is extremely high in a subset of FODMAPs and has helped dramatically.

You would think, but my personal experience is the exact opposite. I actually continue to ask every new doctor the same question and continue to receive the same answer.

I had pretty crazy side effects from biologics (ultimately I feel they made things worse). No one believes sick people though :P

I fully understand where you are coming from, but do not discount the power of diet. I found, that in order to see a real difference, I had to move ~very~ far away from my old habits. It can be a scary thing to do.

Every gastroenterologist I have ever talked to has been ~absolutely certain~ that diet plays no role at all in gut inflammation.

I'm glad to see this mindset start to change.

I'm not sure the best way to judge the quality of a scientific argument is whether it 'feels like good science.'

While the author is obviously only scratching the surface in an article targetted at non-scientists, the several PhDs he cites make decent arguments that are based on a little more than feelings. It would probably be more in line with the ideal of 'good science' to actually investigate the possibilities presented than dismiss them from emotional associations.

It is a worrying trend that the way science feels is increasingly more important than the actual evidence (or lack thereof). One could even describe the current attitude towards science outside of scientitific institutions as religious.

> It's absurd to think any sincere, and representative, member of the environmental movement

This is a powerful no-true-scotsman here. In my experience, the vast majority of people espousing technical solutions to climate change are barely aware of trade-offs if they've considered them at all. Externalized costs are primarily talked about as those imposed by fossil fuels etc. The costs imposed by environmental action itself are not so commonly considered.

> This is pinning all the woes of a particular marginalized group on the environmental movement...

The article simply pointing out that environmentalists aren't really helping here. Increased demand for cobalt and coltan is extremely harmful to certain groups of people who don't have a particularly loud voice in any segment of the environmental movement or the renewable energy industry. No one kills over rocks that have no value. By driving the demand for these minerals, unrest is increased in this region.

It's kinda silly to assume ~all~ environmentalists are fighting for these groups of people when the interests of many segments of the environmental movement are directly opposed to them and the article itself provides examples of environmental groups attacking them. The world is not black-and-white. People with good intentions can harm others.

I don't particularly like language criticisms, but word for word I think there is a lot more meat in your original comment than in this article.

The point of the article is that the philosophy underpinning eco-conscious modernity, specificially the fundemental separation between "humanity" and "nature," leaves no place for humans who live as a part of nature. In the modern world this concept is almost entirely taken for granted, as most of us spend the vast majority of their lives in artificially constructed environments designed specifically to insulate us to the greatest extent possible from the pulse of nature. This is baked in to both our interpretation of the challenges we face and our proposed solution to these challenges, sometimes with unintended consequences.

This article is an invitation to more closely consider this underpinning philosophy. The tone of your response indicates this maybe isn't so easy and also why it is so important.

So do price increases from supply chain shocks. And if you've ever lived paycheck-to-paycheck, you understand that even minor shocks get balloon out of control very quickly because resources are so tightly allocated.

We are just now living through an era where a relatively minor shock is going to have severe implications last several years (which have and will continue to hit the poorest the hardest). This is what happens when you allocate resources too tightly without sufficient slack.

I don't think this is our last pandemic. Really the modern globalized era is a vanishingly small slice of human history. Ancient societies were often wiped out by unexpected events. I would not bet that nothing unexpected will ever happen again. On the contrary, the relatively consistent climate that has sustained literally all of human civilization is changing at an unprecedented rate. I expect frequent major challenges to existing systems. I think COVID is actually a minor challenge in this space; the economic effect is only so large because of how poorly we were prepared.

I reject your constraints. Optimizing for minimum resource wastage and price is also optimizing for minimim reslience to the unexpected. If you want to experience this first hand try living paycheck-to-paycheck. I'd rather pay more and consume less while relying on more resilient systems; I think we need it now more than ever.

Of course not, but I kinda feel like this discussion is splitting hairs. If you accept that killing and eating another being is fine, as long as you aren't going out of your way to cause excessive pain I don't think it's a problem.

And I kinda feel like the difference between factory farming and pasture farming probably has a larger suffering delta than industial slauighterhouses vs Jewish butchers. But for whatever reason people don't care all that much.

Humans very quickly realized that food doesn't always come in at a constant rate and learned to hoard[1] in times of plenty to protect against times of scarcity. As you note, current governments still stockpile food, but before power was so heavily centralized this responsiblity fell to smaller communities and family units. The very first proto-states formed around resource stockpiles[2], but food preservation had been a big deal for much longer, some 12k years ago[3], predating agriculture. In contrast, the expectation that I can go to Walmart and buy fresh ground beef at any time is not even a century old.

Neccesity leads to JIT, but also sustained surplus. If the winters are mild and food can grow year round, why bother stockpiling? If any widget can be obtained quickly and cheaply, why spend the extra effort to maintain inventory? If I can always buy ground beef at Walmart, why should I keep a winter's worth supply in my freezer? These practices are fine as long as the underlying assumptions remain valid. If one suddenly finds that they can't reliably buy toilet paper on demand, there is an incentive to hoard it. And that's exactly what happened.

[1] While it has taken on a somewhat different meaning in recent times, the early meaning of the word was 'to store and preserve for future use.' https://www.etymonline.com/word/hoard

[2] https://www.jstor.org/stable/44687105

[3] https://nchfp.uga.edu/publications/nchfp/factsheets/food_pre...

For most of the pre-modern era, 'governing body' simply means a group with enough stockpiled resources, especially food, to project power. Anyone who could get in on this action tried to. Spoilage is an issue, but humans came up with many neat tricks to work around this, many of which are still used today (fermentation, for example). Anyone who didn't want to live or die soley by the whims of the local warlord during a harsh winter had to maintain their own food stockpile.

The great lie of Civ is to present this as centrally organized when for most of human history this power was very finely decentralized due to the expense of communication and logistics. But as socities become more centralized food stockpiles haven't disappeared. Many governments still maintain food stockpiles, especially poorer countries.

> It’s quite natural, normal humans also don’t hoard everything they can possibly think of needing...

For most of human history we did exactly that. The deeply interconnected "JIT Consumption" world is really quite new. And if consumption patterns suddenly change then you can't buy toilet paper anymore.

I don't understand the obsession with the 'pain-free' death. Surely the animal feels something in all slaughter methods, and either way it's getting killed and eaten. Frankly unless you have even been slaughtered by a Jewish butcher, how can you truly judge how much pain the animal feels?

Besides, most people have experienced a cut by a sharp edge where they don't feel pain or even realize they are bleeding for some time. This is actually a goal of Jewish and Halal butchering methods. And frankly, I'm not sure attempting to perform some 'pain-free' slaughter via impersonal machine is more humane than having another sentient being in close proximity to the animal perform the act. Modern factory slaughter is humane in the same sense a drone strike is humane.

So do you want to correct my incorrect conclusion or are you happy to just call it a day :P

The contradiction was in saying the simulation hypothesis was fundementally unfalsifiable, and then pointing to its falsifiablity as a reason to prefer it to other belief systems. Your edit made it more clear, but there is still a contradiction there.

Given that a sibling comment is expressing very similar criticisms, I think my interpretation of your argument reflects something present in your text. If I am mistaken, please help me understand your point of view better. This is what good faith discussion is about. No shame necessary.

While disagreement is often violent, I think if you look closely most of these disagreements are actually politically motivated rather than reflecting deep divisions in core beliefs. Prior to the advent of nationalism this was simply a good way to rally the troops for whichever geopolitical objective.

In terms of core beliefs, I think your estimate is rather low. Obviously it depends on how you weight it, but the core beliefs of the Abrahamic relgions and even Hinudism and Buddhism have a lot in common.

> At the very least N-1 of N religions are wrong

I will take it further than this: 100% of all beliefs are at least partially wrong. Ultimately, one has to ascribe weight to something.

I'm having a hard time interpreting this; are you saying that because people who believe in religions don't unanimously agree that implies all relgions are false?

> The former is a claim that I made explicitly.

I think you recognized the contradiction in your own point and corrected it so I will leave it be. It is unimportant to the broader idea of the simulation hypothesis that any individual hypothesis can be disproven. In fact there is an infinite number of trivial variants that can easily be disproven. This is still an infinitessimal fraction of the uncountable space of hypotheses.

Similary it doesn't matter if the claims of any individual religion can be falsified, there is simply another one without those claims. Just because I read something false in one book, or many books, doesn't mean all books are false. Or just because one scientfic paper turns out to not be replicable doesn't mean empiricism is fundementally useless.

There is no experiment that can disprove all simulation hypotheses. There is always another hypothesis where that result is simply a valid part of the simulation.

Similarly, there is no evidence that can demonstrably disprove the existence of "God." In fact at the fundemental level these two beliefs are basically identical; the difference is in language and emotional baggage.