Otherwise known as the scientific method, or How Science Works. You were probably taught the basics of this in secondary school/high school/your local equivalent, but the number of physics undergraduates who came through my university not having the first clue about how science works is large enough that I suspect it’s not quite being hammered into people’s brains the way it should be. Which is a shame¹, because not knowing anything about the scientific method is what allows so much anti-science to flourish in the press and media at large. I guarantee you homeopathy – for example — wouldn’t last a second in a world where people were the least bit curious about what was going on under the bonnet, and neither would the hundreds of news “stories” about how chocolate is actually good for us.

So this is going to be a brief précis on how science works with a couple of classic examples thrown in that should hopefully prompt at least a couple of people who read it to not just accept a piece of research’s final conclusions, but instead to spend a second or two looking at their methodology to see if it’s solid and if it adheres to the basic structure of the scientific method. If it doesn’t then there’s a fairly high chance that there’s some commercial bias involved; I know that more than a few of the “chocolate is good for us” pieces are actually funded by chocolate manufacturers who want people to feel less guilty about buying and consuming their product, while the last thing the peddlers of homeopathic pills want is for someone to take a magnifying glass to their method because it makes no scientific sense whatsoever.

Science is an evidence-based discipline. This is the key feature of science, so I’m going to repeat it a couple of times. Science is an evidence-based discipline. Science is an evidence-based discipline. If you don’t have some kind of objective, verifiable evidence that proves what you are saying could be true, what you are doing is not science. Whatever scientific idea you’ve come up with needs to be built on previously existing evidence that provides it with a strong support, otherwise it’s going to collapse alarmingly quickly under the detailed scrutiny of other trained scientists.

Speaking of, science is also based heavily around the concept of peer-review. Scientific research has to be as open as possible, with each stage of the process exhaustively documented so that other people can exactly reproduce that research if they want to. Getting independent confirmation of a result is very important, and so is letting other scientists in the field pick over the details of your research for any flaws. You might have carried out your experiment with the best will in the world and merely reported what you saw at the end of it, but that doesn’t necessarily mean you have done a science. Your apparatus might have been broken in some subtle way. You might have set it up in the wrong place. There might be some other unknown factor at work that you just didn’t think of but which alters the experimental results significantly. Exposing your research method to the rest of scientific establishment means that it’s going to be looked at by dozens of experts in the field² you’re exploring, and vastly decreases the chance of any flaws making it through into the final work.

Anyway, let’s say you do have some kind of coherent scientific idea based on previously-existing evidence. Contrary to what you might think, this is not a theory.  What you have there is a hypothesis, which you might recognise as the thing most experimental research sets out to test. The reason we differentiate hypotheses from theories is because it’s rather easy to tweak a “theory” to fit pre-existing scientific evidence. If you have one cat-shaped jelly mould and somebody uses it to make some jelly, predicting that the jelly is going to come out of the mould in the shape of a cat isn’t exactly going to indicate astounding precognitive abilities on your part because you knew the mould was shaped like that in the first place. It isn’t enough for your nascent hypothesis to make sweeping statements about the universe we already know and think we understand; in order for it to be accepted as a new theory that is better than the currently existing theory, it has to make a unique, experimentally verifiable prediction about the universe that is at odds with – or at least more accurate than – the old theory. It’s easy to come up with a hypothesis that accounts for experimental outcomes that have occurred in the past; it’s rather more difficult to come up with a hypothesis that accounts for experimental outcomes that have yet to occur at all. If you manage it without access to a time machine there’s a very good chance there might be something in your hypothesis.

The most dramatic example of a successful theory overturning an old one in this fashion was when Einstein’s general relativity proved more accurate than Newton’s theory of universal gravitation at predicting the deflection of light as it passed close to a large gravitational source – in this case the Sun. General relativity had already accounted for aberrations in the precession of Mercury that Newtonian gravity couldn’t, but the existence of those aberrations had been known for centuries and it was entirely possible that Einstein might have written his theory with the sole purpose of explaining them away. In order to be accepted general relativity had to predict something new that had never been tested before, and in this case Einstein and Arthur Eddington decided to attempt the measurement of the deflection of light waves by the Sun in 1919. Cavendish had predicted this would happen in a Newtonian universe waaaay back in the late 1700s, but the key difference between Newtonian gravity and general relativity was that Newton’s formulation predicted a degree of deflection that was half that predicted by general relativity. Eddington and other collaborators around the world waited for a total solar eclipse (this being the only time that deflected beams of light wouldn’t be completely drowned out by the ambient light from the Sun) and then measured how much the positions of stars close to the edge of the Sun’s disc appeared to shift from their actual, known positions in space. After they’d cranked through the calculations the result was unarguably final: Einstein’s prediction fell within experimental error of the actual observed deflection of light, while Newton’s was a long way outside it. After this result was independently confirmed Newton’s theory wasn’t exactly thrown out, but it was seen as just an approximation of what was really going on with gravity which was more adequately explained by general relativity.

That’s a good example of the scientific method working exactly how it’s supposed to: a hypothesis is formulated, tested, found to be more accurate than the currently existing theory and subsequently supplants it in the scientific lexicon. It’s also possible for negative outcomes to result in this rewriting of the scientific handbook; just look at Michelson and Morley’s interferometer experiment back in 1887. Before we understood that space is a near-total vacuum it was thought that in order for light waves to make it to the Earth from the Sun (as well as other sources) it would need some medium through which it could propagate, like ocean waves propagate through water and sound waves propagate through the air. Scientific orthodoxy therefore held that the entire universe was permeated by a substance called the lumineferous aether through which light could travel. Such a medium would have produced fluctuations in the velocity of light depending on which way the Earth was travelling at a given time, and so Michelson and Morley built an experiment that would show these velocity shifts as an effect of the Earth’s motion against the “aether wind”³. They were rather surprised when they discovered that the speed of light was completely invariant no matter which way the Earth was going, which neatly disproved the whole concept of the lumineferous aether in the first place and directly led to Einstein’s formulation of special relativity two decades later.

Not being able to account for a subsequent experimental result can lead to the death of an old theory even if there’s nothing to replace it. This is the core of the scientific method; not only do theories have to make it through this arduous process of formulation, testing and gradual acceptance into the scientific mainstream, but they have to be on their metaphorical toes even after they’ve made it in life as one null result could end up invalidating the whole thing. Scientific theories are constantly – constantly – being tested in this way to increasingly insane degrees of accuracy, and so you can be sure that anything that still carries the “theory” nomenclature is about as correct as we can make it. Anyone who says “But it’s just a theory!”⁴ is betraying their basic ignorance of how science works and probably has trouble tying their shoelaces in the morning to boot. The Big Bang may have happened 13.7 billion years ago but Big Bang theory has made several crucial predictions about the universe which have subsequently been confirmed experimentally. Evolution is trickier to spot in action, but even there the weight of observed evidence supporting the theory’s case both before and after its formulation is so overwhelming that it is (so far) the only plausible explanation for that observed evidence. The scientific method isn’t without its flaws – there’s an old adage that new theories are only fully accepted once the supporters of the old theory physically die out – but it’s the best we’ve been able to come up with and it is astoundingly successful.

Next week: what happens when people ignore the scientific method, otherwise known as “making stuff up”, otherwise known as “newspapers will print anything because journalists don’t understand how science works,” Hopefully you do now, though.

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1. Actually what I want to say here is that it’s a tragic shortcoming in our societal attitudes that science is perceived as a “hard” subject and something that should be mostly left to experts, which allows anyone who can dress themselves up like an expert to peddle whatever crap they want under the guise of science.
2. Peer-review isn’t perfect by any means, as the various scientific paper databases are set up so that they’ll prioritise research that is referred to a lot by other people. This is reasonable, as a paper that gets mentioned a hundred times in the reference sections of other papers is probably a very important piece of work, but it can also turn the submission process into a Kafkaesque version of social media where some of the people commenting on the work you’ve done have a vested interest in getting you to mention their research at some point in order to increase their pageviews. You would be amazed at how petty things can get, especially in niche areas of research.
3. The lumineferous aether was supposed to be moving relative to the Sun’s motion around the Milky Way, meaning that the Earth’s motion around the Sun should have produced apparent shifts in the relative velocity in the aether wind – think running down a track on a still day and nevertheless feeling the movement of air around your body. By taking measurements six months apart when the Earth was travelling in completely different directions through space it was expected that this would produce a large shift in the relative velocity of the aether wind that would be reflected in the light waves that travelled through it and showed up on an interferometer. It didn’t.
4. The notable exception here being string theory. I’ve gone over my objections to string theory before and I’m not entirely sure how it’s ended up with the “theory” moniker since it is entirely based on pre-existing scientific evidence and has never – and probably will never – be experimentally verified in any way that counts.

The post The Theory Of Theories. appeared first on The Scientific Gamer.

Princess Josh asks:

Do we have any idea when we will run out of science?

I mean, the rate of scientific progress is generally considered to have increased exponentially over the course of the last six to eight millennia, to the point where we’re learning more about physics and the universe each decade than we did in the entire millennium from 0AD (that may be only approximately true, but you get the idea). Does human science progress have an answer to the question of what the limits of human scientific progress might be? Is there a risk of a dead end that humans, no matter how ingenious, will never be able to circumvent?

This is a tricky one for two reasons.

One: Attempts to predict the future of science are almost invariably hilariously inaccurate.

Thomas Kuhn came up with the concept of scientific paradigms and paradigm shifts in his 1962 book The Structure of Scientific Revolutions (a rather dense work, but worthwhile if you want to understand how science works). A paradigm can essentially be boiled down to an accepted scientific worldview – that is, we think the world works this way, and we come up with a whole host of scientific theories that use the rules and assumptions of that paradigm. However, those theories are also implicitly and constantly testing the paradigm, and as soon as we make a scientific observation that’s provably inconsistent with our accepted scientific worldview we have to either modify it so that it will accept the anomaly, or else toss it out entirely and come up with a new paradigm. This is a paradigm shift, the transition from one scientific paradigm to another.

Previous famous examples of paradigm shifts include the shift from geocentrism (the celestial model that had the Earth at the centre of the universe) to heliocentrism (replacing the Earth with the Sun) provoked by Nicolas Copernicus, as well as Einstein’s theory of general relativity usurping two hundred years of Newtonian mechanics¹. The new theory is always more accurate than the one preceding it – and we know this because it will usually explain everything the old theory explains plus some new stuff – but we have no way of knowing if it is 100% accurate. In the case of general relativity it’s almost certainly incomplete, since attempts to reconcile general relativity (the science of the very large) with quantum mechanics (the science of the very small) have so far only resulted in non-provable quasi-scientific ideas like M-theory, but even theories that have so far stood up to every test science can throw at them – conservation of energy, for example – would have to be thrown out and replaced with something better² if we found just one definite occurrence of it being incorrect.

This is the basic principle behind the scientific method and it’s carried the human race a very long way over the last few centuries. However, it has one tiny snag: every scientific theory has the potential to be wrong, but you don’t know that it is wrong until you have the evidence sitting in front of you. Until that happens you’re in the rather frustrating position of having to cross your fingers and hope for the best. Amongst other things, this makes it incredibly difficult to see a paradigm shift coming more than a decade or so in advance. Scientists are therefore a little bit wary about making predictions about the future prospects of science these days. Nobody wants to be viewed by posterity as another Lord Kelvin, who once asserted that “There is nothing new to be discovered in physics now. All that remains is more and more precise measurement.” A few years later Einstein tore down Newtonian mechanics with his paper on special relativity, and the following decades saw the incipience of quantum mechanics and particle physics as scientific disciplines. Kelvin was a smart man and a fine scientist, but he fell into the trap of thinking that there was one absolute way of thinking about the universe. There isn’t. There is only a current paradigm.

Two: It is difficult — if not impossible — to disentangle the mutual effect that scientific progress and technological progress have on each other.

Science improves technology, and technology improves science. They’re two sides of the same coin; a new scientific theory allows new technologies to be developed, and no matter what your new technology is – a new computer chip, a new material, a new way of generating a laser – the chances are that someone somewhere will be able to use it in an experiment to test/refine/come up with another scientific theory. Computers are probably the most dramatic example here; pretty much all the work being carried out in modern scientific laboratories wouldn’t even begin to be feasible without the modelling capabilities of modern computers. Sixty years ago computers were just small enough to fit into several rooms and the president of IBM predicted there would be no need for more than five computers in the world. Today we have computers which fit in the palms of our hand which have thousands of times more computing power than the behemoth machines of yesterday, and there are billions of them.

Like scientific paradigm shifts, nobody saw this technological paradigm shift coming, and yet today’s society simply couldn’t function without technologies that were in their infancies just two decades ago. The same is true of science. Leaving aside the science fiction future of Ray Kurzweil’s singularity, while it is impossible to predict the future with any degree of accuracy it is likely based on the last few decades that the pace of scientific and technological change will continue to increase. There are some discrete physical barriers/limitations that have to be overcome – dwindling resources, data storage/processing issues, and human brains being inefficiently squishy collections of neurons that have trouble comprehending the latest scientific theories without at least ten years of dedicated study – but it would be very unwise for me to say that one of these barriers is going to bring humanity’s technological progress to a screeching halt. When confronted with an obstacle science tends to provide its own solution in the form of a new technology. Nanotechnology and fusion could fix the resource problem. Quantum computing could give us more processing power than we would ever reasonably need. And if anyone ever develops a true AI, and its first reaction upon becoming self-aware and seeing the human race isn’t to send legions of Arnold Schwarzeneggers to kill us all, that AI could instantly grasp concepts that it would take a human years to get to grips with.

The operative word here is could. Some of these things could happen. None of them could happen. We could all be living in the nerd rapture a couple of centuries from now, or the human race could be reduced to a last few pitiful survivors squabbling over the last can of dog food in a Mad Max-esque apocalyptic future. What I am trying to get across here is that attempting to predict the long-term future of science and technology is a loser’s game. Most people who try get it wrong, and those who get it right do so more out of serendipity and sheer dumb luck than they do because they saw which way the wind was blowing. The best thing that we can do is stop worrying about what might lie beyond this scientific event horizon and instead focus on what we can do now³. If we don’t, then we’ll never even get there.

1. Newtonian mechanics still function perfectly adequately as an approximation for literally every single body that you as a human being are likely to encounter in your lifetime, which is why you still get taught Newton’s laws in secondary school. They also have the advantage that they are relatively simple and easy to understand, whereas general relativity requires graduate-level schooling in order to fully grasp it.
2. Conservation of energy is pretty much the most solid scientific principle there is, and it is incredibly unlikely that it would ever be proven wrong. However, if it ever was it would be very bad news for science, since conservation of energy acts as the foundation for myriad other theories and assumptions. You’d pretty much have to dismantle all of physics and rebuild it again from the ground up.
3. Where “now” means “the next half-century”. Long-term planning horizons are something which often elude today’s politicians, but I’m not seriously advocating we go into the future blind just because it’s a little difficult to tell where humanity is going to wind up in a hundred years’ time.

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