Trusting the science
|Let’s check the science: Why should I trust science ahead of other knowledge?|
I have friends who accept all sorts of pseudoscientific ideas – astrology, homeopathy, channeling, energy medicine, to name a few. We occasionally argue about their validity, and usually end up at a stand-off. I point out that there is no scientific evidence to support them, and in many cases there is evidence to show they are nonsense. They adopt the position that science can’t claim the final word – that there are other sources of knowledge that have authority to match or even overrule science. Why are they wrong?
Why science is different.
A tragic side-effect of our democratic lifestyles is that so many people believe all opinions are equally valid. This is, of course, nonsense. All opinions have equal rights to be heard, but that says nothing about their validity. Believing something very strongly counts for nothing in judging its worth. As I’ll show in the next section, scientific knowledge isn’t just opinion or narrative or dogma or faith or social construct. It’s a painfully-assembled account of what’s really there in the natural world. And don’t make the mistake of thinking that the scientific process is used only by people in white lab coats. Historians, crime-fighters, journalists and countless others use its methods all the time
What is it about science that makes it trustworthy?
Science is the best method of finding out about the natural world. That’s because it has evolved a whole kit of strategies for minimizing errors due to normal human failings, biases and faults in reasoning. Individual scientists can be jealous, proud, frustrated, sneaky, naive, misled and so on, just like everyone else. But nearly always, all of that comes out in the wash of the scientific process, leaving just the evidence. We don’t need to trust individual scientists because science is a communal activity and it does not rest on authority.
Here’s why it’s the best method. When the scientific community investigates a problem:
- Scientists come up with models that include mechanisms and are falsifiable. At first, there may be several models in contention and they need to fit coherently with other scientific models.
- The models are tested in the real world. Models that aren’t supported by the evidence are rejected.
- Reports describing surviving models, the tests that were used and their supporting evidence are published in journals.
- The scientific community gives feedback. The reports are reviewed by other scientists both before and after publication. Sometimes the tests are replicated as a check.
- Usually, a single model emerges as the one that fits the evidence best.
- Even so, every scientific model remains tentative. There is always the possibility it may be replaced by a better model.
This process doesn’t happen overnight. It takes time for a new model to be fully accepted by the scientific community.
What about all the errors and reversals?
Of course, the scientific process is not perfect. Sometimes scientists make mistakes that go undiscovered for a long time. Sometimes they actually cheat. But that happens very rarely, and sooner or later it’s detected and rectified.
Science is very competitive and that’s one reason why there are often reversals in scientific knowledge. Nothing boosts a scientist’s career like the overturning of some existing model. Previous knowledge is constantly being challenged. ‘Good cholesterol’ (HDL) may not protect against heart disease after all; a review shows that the benefits of PSA screening for prostate cancer don’t outweigh the harms; we now know the earth is warming, not heading for another ice age. But claims of faster-than-light neutrinos overturning the theory of relativity were shown to be wrong: so were claims of cold fusion and polywater.
Does this mean scientific findings can’t be trusted? Not at all. It’s not a good idea to have supreme confidence in a single study, but once a model is supported by multiple independent lines of evidence from a large number of studies, it’s a different matter. A large part of our scientific knowledge falls into this category. So, if science tells you (as it does) that the mechanisms proposed by homeopathy don’t make sense and that numerous randomised controlled trials show that homeopathy is no better than a placebo, you can be pretty sure that’s correct. And if science tells you (as it does) that numerous lines of evidence show that the earth is warming and humans are the main cause, then that’s pretty sure to be the case.
The temptation to side with the outsider
Humans have a tendency to sympathise with a maverick who battles against a powerful foe and many promoters of pseudoscience cast themselves in this role. History shows that maverick ideas nearly always end up on the scrap-heap. They often rely on anecdotal evidence, which settles nothing. If mavericks want their models to be taken seriously, there’s only one thing for it. They need to follow the scientific process, as outlined above.
Of course, mavericks often claim that it’s impossible for them to gain any traction in the scientific community because it’s conspiring against them. The idea that thousands of scientists collude to prevent ‘unwanted’ discoveries being made public is absurd. Any conspiracy that involves more than a handful of people is certain to be discovered. Conspiracy theories are the last resort of those who can’t produce evidence in support of their ideas.
What about the deeper truths?
It’s fair enough to have the opinion that science can’t address all problems. Most scientists would agree. But to imagine there is some mysterious alternative or better process is just wishful thinking, Every process that makes this claim can actually be reduced to a reliance on faith.
To those who say they have evidence that transcends science I say this: You may have a rudimentary model with some sort of mechanism. If it’s not falsifiable, it’s worthless. If it is falsifiable, it’s worthless without the hard work of testing and finding supporting evidence. It’s just possible that your model is better than the accepted one, but the chances of this are remote. The argument that you must be right because science hasn’t proved you wrong doesn’t hold water. And if you cling to your model when science has examined it and found that it doesn’t stand up, you can’t escape being labelled a denier.
Science is valid because it is tested exhaustively in the real world, its knowledge is public and it doesn’t depend on anyone’s authority. The rigorous evidence and reasoning, the arguments and counterarguments are there for anyone to see. As a way of finding out the truth about the real world, nothing can match it.
|This is one of ScienceOrNot’s Let’s check the science series.|
Cartoon from xkcd.