Matrix multiplication

Could somebody explain to me, in a way I'd actually understand, how to (remember how to) go about multiplying a pair of matrixes? I've looked at Wikipedia, I've read linear algebra books up to where they supposedly explain matrixes, and I keep bouncing up against a mental wall where I can't seem to remember how to figure out how to get the answer.

This may not be strictly statistical, but I would choose the idea that in order to make any meaningful statement with data, you always have to have something to compare it to.

Like someone will always come in some political thread and say , "X will increase/decrease Y by Z%.) And my first thought in response is always, "Is that a lot?"

For a recent example I saw, someone showed a graph of Japanese student suicides as a function of day of the year. There were pretty high spikes (about double the baseline value) on the days corresponding to the first day of each school semester. The poster was attributing this to Japanese school bullying and other problems with Japan's school system.

My first thought was, "wait. Show me that graph for other countries. For the world, if such data has been reliably gathered." If it looks the same, it's not a uniquely Japanese problem. What if it's worse in other countries, even?

Yeah, I'd really like to see people stop using information where it doesn't mean anything in isolation. A lot of people think that controls in science exist to make sure that the effects you see aren't spurious or adventitious. It's not like that's wrong, but it's deeper and even more fundamental than that.

I'm a scientist, so let me give you an example from my research (grossly simiplified and generalized for brevity).

Substance A was designed such that it manifests an as-of-yet unexplored type of structural situation. We then carried out a reaction on substance A to see what some of the effects of this situation are. Something happened.

So, if we were to leave it at that, what would we have learned? Nothing. We need substance B, which does not have that siutation going on but is otherwise as similar to A as we can make it, to see what IT does, to see if it does anything different than A. See, we need to do the experiments on both B and A not to see whether the results of A are 'real'. We need to do it to see what the results even ARE in the first place.

Why do people believe that AI is dangerous? What direct evidence is there that this is likely to be the case?

I don't really buy it. The world is changing too fast. Things are way different now than they were in the 50s, so I don't think the statistics from then really mean much anymore.

In another 50 years what will the landscape look like? who knows? Maybe the diseases won't really be such a huge problem because our anivirals will become as good as our antibiotics.

The one thing that can be said with pretty high certainty is that for the most part it will be a completely different world in the second half of the 21st century.

Looking at stuff in the second half of the 20th century to predict the 21st isn't going to cut it, the same way that looking at politics and wars in the 1860s wouldn't produce any useful results about the 1960s.

Map legs to holes. Wrong legs-to-holes? 180 about Z. Inside out? Flip along Z, 180 about Y. Repeat until satisfied. Profit.

I'm rephrasing

I tend to think of things in motion before I fully understand them in their static forms

As "I think of solutions before thinking of desirable outcomes or the current situation". It sounds like a small, silly example of premature solution-generating, keyed deep into System 1. Fascinating. Maybe a solution is to train "what outcome do I want?" to be primed by any moment of confusion. Since the principle scales to more considerable problems, having it as a knee-jerk reaction could be worthwhile.

We can't take reality for granted. Most interesting things we see are simulations. For example, I see Mars. Most likely I see it on TV, or in dream, or in a book. So in most cases we need to invest to prove that the object is real, not that it is simulated. Most time we see images or dreams, not real things. So even in our world most experience are simulations. If I say you that I have a palace with 100 rooms, most likely I lie. So being skeptical means not believe in reality of anything, especially large and expensive.

Of course, it would be premature to start to believe that we are in the simulation without any practical evidence. But we should give simulation hypothesis higher a priory probability.

I don't think I'm in a simulation, and I only just now reading this became able to verbalize why that is.

I reject as a premise any arguments that rely on some kind of 'probability that I find myself as me'.The reason for this is that I don't think that such probabilities can be considered to exist. You may say that I could have been born a hunter-gatherer thousands of years ago, some guy living in the future, or some guy living in a simulation in the future, but I don't think that these really work as potentialities. The hunter-gatherer's experiences are different than mine, as are those of the future people. I am myself, and am a unique structure that has unique experiences. My 'consciousness' is what it's like to occupy this particular area of spacetime. The hunter-gatherer, future man, and simulation man have their own consciousness, but they are different than mine. In some ways it works to talk about these entities with similar structures as a class (people), but I don't think it works in the way some people think it does. People aren't electrons. Each individual is different, and thus the descriptor is only a classification to generalize about some general pattern that keeps coming up.

Basically, they all either exist or don't, so it's not like I should be surprised to find myself as myself. Everyone finds themself as themself.

And I also tend not to take argumentation as strong evidence for anything, because above all it has a lot of problems of interpretation. Sure it may sound convincing, but how do we know there isn't some flaw in the reasoning that we don't see? For everyday things, it's not such a big issue, but when we start going into things positing the existence of entire universes, I think it's gone far beyond the domain where it can be reliable. The fundamental assumptions we're making that we don't know we're making start to pile up and matter a lot. For example, imagine trying to argue about time before the concept of relativity had been imagined? Zeno's paradoxes before calculus? You're just not playing with the right deck, and a lot of the time you won't even realize it.

This problem is still pretty huge with empirical information, but there it seems a lot more manageable (read: sometimes, it's POSSIBLE to manage it).

I know very well a registered dietitian who deeply knows her stuff. She's explained quite a lot to me, and given me considerable knowledge (it helps that my field is chemistry, and while biochem is different than what I do it's not completely alien).

Unfortunately I can't say much about nutrition in one single post. Like so many things, it's a really complex and rich science and to really know something about it would take years of education on the subject. As you may imagine, everything comes with lots of exceptions and qualifiers. My recommendation if you really want to learn this stuff is to talk to a registered dietitian (any quack can call themself a neutritionist, but RD is a protected title), or read recent academic textbooks (NOT popular books) on nutrition.

About the subject matter in the main post, from my knowledge, meat and heavily processed foods tend to be more in the territory of things that are worse to eat a lot of. I can pretty certainly say it's true that many people would do better to eat considerably less of that stuff than they do.

Speaking from my area of expertise now, I'll say that it's pretty silly from a thermodynamics standpoint to eat meat. You can do fine as a vegetarian, and raising plants to eat is significantly more energy efficient than raising plants to feed animals to eat. Animal raising leads to a considerable amount of energy waste, as well as material pollution. I don't have the numbers on hand, but it's enough to be a significant factor. So what do I do? I don't eat meat very often.

"Your perception of the 'quality' of works of art and litterature is only your guess of it's creator's social status. There is no other difference between Shakespeare and Harry Potter fanfic - without the status cues, you wouldn't enjoy one more than the other."

Is anyone aware of the explanation behind why technetium is radioactive while molybdenum and ruthenium, the two elements astride it in the periodic table are perfectly normal? Searching on google on why certain elements are radioactive are giving results which are descriptive, as in X is radioactive, Y is radioactive, Z is what happens when radioactive decay occurs, etc. None seem to go into the theories which have been proposed to explain why something is radioactive.