posted on 20 March 2017
from The Conversation
We take science seriously at The Conversation and we work hard to report it accurately. This series of five posts is adapted from an internal presentation on how to understand and edit science by our Australian Science & Technology Editor, Tim Dean. We thought you might also find it useful.
If I told you that science was a truth-seeking endeavour that uses a single robust method to prove scientific facts about the world, steadily and inexorably driving towards objective truth, would you believe me?
Many would. But you shouldn’t.
The public perception of science is often at odds with how science actually works. Science is often seen to be a separate domain of knowledge, framed to be superior to other forms of knowledge by virtue of its objectivity, which is sometimes referred to as it having a “view from nowhere".
But science is actually far messier than this - and far more interesting. It is not without its limitations and flaws, but it’s still the most effective tool we have to understand the workings of the natural world around us.
In order to report or edit science effectively - or to consume it as a reader - it’s important to understand what science is, how the scientific method (or methods) work, and also some of the common pitfalls in practising science and interpreting its results.
This guide will give a short overview of what science is and how it works, with a more detailed treatment of both these topics in the the final post in the series.
What is science?
Science is special, not because it claims to provide us with access to the truth, but because it admits it can’t provide truth.
Other means of producing knowledge, such as pure reason, intuition or revelation, might be appealing because they give the impression of certainty, but when this knowledge is applied to make predictions about the world around us, reality often finds them wanting.
Rather, science consists of a bunch of methods that enable us to accumulate evidence to test our ideas about how the world is, and why it works the way it does. Science works precisely because it enables us to make predictions that are borne out by experience.
Science is not a body of knowledge. Facts are facts, it’s just that some are known with a higher degree of certainty than others. What we often call “scientific facts" are just facts that are backed by the rigours of the scientific method, but they are not intrinsically different from other facts about the world.
What makes science so powerful is that it’s intensely self-critical. In order for a hypothesis to pass muster and enter a textbook, it must survive a battery of tests designed specifically to show that it could be wrong. If it passes, it has cleared a high bar.
The scientific method(s)
Despite what some philosophers have stated, there is a method for conducting science. In fact, there are many. And not all revolve around performing experiments.
One method involves simple observation, description and classification, such as in taxonomy. (Some physicists look down on this - and every other - kind of science, but they’re only greasing a slippery slope.)
Philosopher is out of frame on far right. xkcd
However, when most of us think of The Scientific Method, we’re thinking of a particular kind of experimental method for testing hypotheses.
This begins with observing phenomena in the world around us, and then moves on to positing hypotheses for why those phenomena happen the way they do. A hypothesis is just an explanation, usually in the form of a causal mechanism: X causes Y. An example would be: gravitation causes the ball to fall back to the ground.
A scientific theory is just a collection of well-tested hypotheses that hang together to explain a great deal of stuff.
Crucially, a scientific hypothesis needs to be testable and falsifiable.
An untestable hypothesis would be something like “the ball falls to the ground because mischievous invisible unicorns want it to". If these unicorns are not detectable by any scientific instrument, then the hypothesis that they’re responsible for gravity is not scientific.
An unfalsifiable hypothesis is one where no amount of testing can prove it wrong. An example might be the psychic who claims the experiment to test their powers of ESP failed because the scientific instruments were interfering with their abilities.
(Caveat: there are some hypotheses that are untestable because we choose not to test them. That doesn’t make them unscientific in principle, it’s just that they’ve been denied by an ethics committee or other regulation.)
There are often many hypotheses that could explain any particular phenomenon. Does the rock fall to the ground because an invisible force pulls on the rock? Or is it because the mass of the Earth warps spacetime, and the rock follows the lowest-energy path, thus colliding with the ground? Or is it that all substances have a natural tendency to fall towards the centre of the Universe, which happens to be at the centre of the Earth?
The trick is figuring out which hypothesis is the right one. That’s where experimentation comes in.
A scientist will take their hypothesis and use that to make a prediction, and they will construct an experiment to see if that prediction holds. But any observation that confirms one hypothesis will likely confirm several others as well. If I lift and drop a rock, it supports all three of the hypotheses on gravity above.
Furthermore, you can keep accumulating evidence to confirm a hypothesis, and it will never prove it to be absolutely true. This is because you can’t rule out the possibility of another similar hypothesis being correct, or of making some new observation that shows your hypothesis to be false. But if one day you drop a rock and it shoots off into space, that ought to cast doubt on all of the above hypotheses.
So while you can never prove a hypothesis true simply by making more confirmatory observations, you only one need one solid contrary observation to prove a hypothesis false. This notion is at the core of the hypothetico-deductive model of science.
This is why a great deal of science is focused on testing hypotheses, pushing them to their limits and attempting to break them through experimentation. If the hypothesis survives repeated testing, our confidence in it grows.
So even crazy-sounding theories like general relativity and quantum mechanics can become well accepted, because both enable very precise predictions, and these have been exhaustively tested and come through unscathed.
The next post will cover hypothesis testing in greater detail.
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