This is just sleight of hand. It's true that science can never be certain about anything, not to the same level as mathematics.
But otherwise, there is nothing special about positive or negative statements. You can express any positive statement as the negation of a negative statement, so to the extent that science can "disprove negatives", it can equivalently "prove positives".
Here is a lengthy interview where he discusses this at length (with a timestamp where he says exactly that String Theory, the precise mathematical model, doesn't describe the real world):
Note that he still thinks that there is a way to produce some kind of similar theory, "a string theory" as opposed to "String Theory", could be the best answer.
According to this Reddit thread, he doesn't say it's "dead in the water" at all. It's just a version of string theory.
This is what I'm afraid of. People who aren't qualified spreading fake news on string theory.
I don't claim to be qualified. I just want to call out HN people who are extremely confident that string theory is dead but has no background in physics.
You can listen to the podcast yourself. I explained my own understanding of his position: that String Theory, the specific mathematical structure, is categorically not a good model of the real world. He does believe that it is possible to create a different theory inspired from String Theory, "a slightly expanded version of String Theory", that could be correct. But, he also says that no version of a string theory that exists today fulfills this role.
Now, if by "string theory is dead in the water" someone means that "working on a generalization of string theory is a bad idea", then they are wrong, Leonard Susskind doesn't believe that.
But if by "string theory is dead in the water" they mean "there is no point in studying String Theory deeper, with its general mathematical properties, maybe with a slight tweaks, as it is right now it can't describe the real world", then this is quite clearly professor Susskind's position.
This is a bit of a technicality, but we don't live in a 4D world, we live in a 3+1D world - the 3 spacial dimensions are interchangeable, but the 1 time-related dimension is not interchangeable with the other three (the metric is not commutative).
I'm bringing this up because a lot of people seem to think that time and space are completely unified in modern physics, and this is very much not the case.
To expand on this a little for those interested, time has properties space doesn't. For example, you can turn left to swap your forward direction for sideways in space. You cannot turn though, in a way that swaps your forward (as it were) direction in space for a backward direction in time.
Equally, cause always precedes effect. If time were exactly like space, you could bypass a cause to get to an effect, which would break the fundamental laws of physics as we know them.
There's obviously a lot more, but that's a couple of examples to hopefully help someone.
Not really. Even the electric force is not purely time symmetric - you have to flip the sign of the charge if you want to flip the direction between forwards vs backward in time.
Even worse, the weak force breaks another symmetry as well, parity symmetry (which basically means that moving backward in time, weak force particles "look" like their mirror image, instead of looking the same).
Can you expand on this? I’m guessing that it’s something to do with preservation of mass & energy? Like mass doesn’t have to be preserved over a spatial dimension (eg rotating an object) but does over time.
I explained in another comment, but it's more fundamental than that.
In pure mathematical terms, the vector space used in special relativity (and in theories compatible with it, such as QM/QFT), while being 4 dimensional, is not R^4, it's not a 4D cartesian vector space.
Specifically, the scalar product of two vectors in R^4 (4D space) is [x1,y1,z1,h1] dot [x2,y2,z2,h2] = x1x2 + y1y2 + z1z2 + h1h2. You can order the coordinates however you like - you could replace x with h in the above and nothing would change.
However, SR space-time is quite different. The scalar product is defined as [x1,y1,z1,t1] dot [x2,y2,z2,t2] = c^2 * t1t2 - x1x2 - y1y2 - z1z2. You can still replace x with y without any change with the result; but you can't replace x with t in the same way. This makes it clear from the base math itself that the time dimension is of a different nature than the 3 space dimensions in this representation. This has a significant impact on how distances are calculated, and how operations like rotations work in this geometry.
How is the difference between them characterised in physics?
It seems like it would be hard to distinguish from the point of view of a 4D unit vector XYZT if T was massively larger. Is it distinguished because it's special or is it just distinguished just because the ratio to the other values is large.
Imagine if at the big bang there was stuff that went off in Z and XY and T were tiny in comparison? What would that look like? Part of me says relativity would say there's no difference, but I only have a slightly clever layman's grasp of relativity.
The difference is this: in regular 4D space, the distance between two points, (X1 Y1 Z1 T1) and (X2 Y2 Z2 T2) is (X1-X2)^2 + (Y1-Y2)^2 + (Z1-Z2)^2 + (T1-T2)^2), similar to 3D distances you may be more familiar with.
However, this is NOT the case in Special Relativity (or in QM or QFT). Instead, the distance between two points ("events") is (cT1-cT2)^2 - (X1-X2)^2 - (Y1-Y2)^2 - (Z1-Z2)^2. Note that this means that the distance between two different events can be positive, negative, or 0. These are typically called "time-like separated" (for example, two events with the same X,Y,Z coordinates but different T coordinates, such as events happening in the same place on different days); "space-like separated" (for example, two events with the same T coordinate but different X,Y,Z coordinates, such as events happening at the same time in two different places on Earth); or light-like separated (for example, if (cT1-cT2) = (X1 - X2), and Y, Z are the same; these are events that could be connected by a light beam). Here c is the maximum speed limit, what we typically call the speed of light.
This difference in metric has many mathematical consequences in how different points can interact, compared to a regular 4D space. But even beyond those, it makes it very clear that walking to the left or right is not the same as walking forwards or backwards in time.
Edit to add a small note: what I called "the distance" is not exactly that - it's a measure of the vector that connects the two points (specifically, it is the result of its scalar product with itself, v . v). Distance would be the square root of that, with special handling for the negative cases in 3+1D space, but I didn't want to go into these complications.
Most branches of hinduism condemn meat eating, so this has created a significant pressure against meat production (same as you'll find little production of pork in the Middle East and North Africa). This is not universal, of course, because historically many regions of India had large meat-eating muslim populations as well.
Note that this is typically lacto-ovo-vegetarianism, not veganism.
The first thing on the website is indeed broccoli. But the first thing in the new inverted pyramid, both on the website and in other graphics of it, is meat. In fact, on the website, when you first get to "The New Pyramid", you'll first see only the left half, the one that has meat and other proteins; you'll have to scroll more to see the right half with vegetables and fruit.
I don't think it is meant to read left to right but top to bottom. Chicken and broccoli are top center, and that is the standard weight lifter meal plan. That said, human dietary needs vary individually by far more than any lobbied leaders will ever communicate.
The website is animated, so there's no question of which direction to read in, the left side literally pops up first lol. I can't lie, I miss websites that stood still, this could've just been a PDF.
BTW, you say "lobbied leaders" -- if you're talking about the scientists who have their names on this report, you'd be very correct. The "conflicting interests" section has loads of references to the cattle and dairy industries.
That phrase suggests more that the author believes this is done for spectacle, knowing that it will attract attention to the researcher far more than a nice-looking painted statue would. Basically he seems to be accusing these researchers of doing flame-bait for clicks, like those kitchen-top meal TikTok videos designed to get engagement by making people angry.
The problem is not a lack of naturalism, it's obvious mistakes in the way the naturalistic poses are attempted. Many of Rublev's icons have obvious mistakes in the way joints are painted, for example - but not all of them or the exact same thing; it's not a style, it's simply a limitation of his skills. Many later painters who were inspired by him have corrected this mistake, not sought to reproduce it.
Not to mention, Rublev lived at the end of the Medieval period, and well into the Renaissance - the period where painterly skill in Europe was revitalized.
Again, I’m not sure why it matters. Henri Rousseau couldn’t draw for shit and yet people adore his art. The represented idea and its aesthetic execution are what people mostly respond to, not how realistic a figure’s joints happen to be. (And FWIW, a large number of Renaissance painters clearly have no idea what a female body looks like.)
While that would be miles better, there's still plenty wrong with it. Most advertising is designed to trick people into either buying something that they don't need at all (e.g. consuming more soda instead of drinking water, or getting some gadget, or more clothes than they need), or into buying the an objectively worse option (e.g. buying a more expensive fridge that will actually last less time). This is the goal of B2C advertising: tricking people to behave less rationally in their consumption behavior.
The only way to avoid this is to just block ads - even unobtrusive content-relevant ads. You may think ads can't trick you, but that has been shown time and time again to be false.
It's not impossible that people would pay Firefox that much yearly to keep their current user-base from using ad blockers. However, what is impossible is to imagine Firefox would have anything close to their current user base if people were prevented from using ad blockers. Most likely they would shrink to almost 0 users overnight if they did this. There are very few reasons to use Firefox over Chrome or Safari (or even Edge) other than the much better ad blocking (or any ad blocking, on mobile).
That doesn't explain the apparent market share of 2--3%, which is still quite large if you think about.
I believe most non-techie users are just lingering, using Firefox just because they used to. Since Firefox doesn't have a built-in ad blocking and the knowledge about adblocking is not universal (see my other comment), it is possible that there are a large portion of Firefox users who don't use adblockers and conversely adblocking users are in a minority. If this is indeed the case, Mozilla can (technically) take such a bet as such policy will affect a smaller portion of users. But that would work only once; Mozilla doesn't have any more option like that after all. That's why I see $150M is plausible, but only once.
Of course, I don't know the actual percent of FF users that use ad block. But I think it's far more likely that it is a majority of current FF users, rather than it being a negligible minority. I think 2-3% of web users is not an implausible approximation of how many people use ad block overall on the web. It's not an obscure technology, it's quite well known, even if few people bother with it.
Edit: actually I'm way off - it seems estimates are typically around 30-40% of overall users on the web having some kind of ad blocker. So, the Firefox percentage being 60-80+% seems almost a given to me.
But otherwise, there is nothing special about positive or negative statements. You can express any positive statement as the negation of a negative statement, so to the extent that science can "disprove negatives", it can equivalently "prove positives".
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