Science and Truth

What is the difference between a theory, a hypothesis and a law? A fact and an observation? At what point do facts become the truth? Is “practicing science” the same as interpreting observations? And if so, does it follow that there are alternative interpretations that are equally valid?

The questions may seem very appropriate to the current political climate. Many feel that science is under assault. People have moved en masse to stand up, march, protest and shout out for science. As a citizen, I stand with them. There are issues that require immediate political action — action on climate change, protection of vulnerable habitats and loss of biodiversity — and doubting the science behind these is dangerous. It is dangerous for our wellbeing and the health and wellbeing of our children. However, it is important to acknowledge that the questions above are not new. They are relevant, important and have been asked by humans for generations before us. In fact, there is an entire branch of philosophy dedicated to addressing these. It is called epistemology.

Being clear on these questions is part of practicing science, and whilst there are no undisputed definitions*, below are some simple guidelines.

What is the difference between a fact an an observation?

An observation is one data point. The best observations are not dependent on the observer. At first, that might seem contradictory. But think about it — there are many reasons why a human observer might be unreliable. Our senses are often deceived. This is one of the many reasons why instruments are so useful — the best are not biased, they are consistent and objective. Sir Isaac Newton did not “discover” gravity by observing a falling apple. He proposed the theory of universal gravitation by measuring the speed at which many different types of objects fell. He also measured the distance between stars etc etc. Observations are important. They are the beginning of a thought process, and the beginning of the scientific process. The best scientists are the keenest observers.

Facts are more concrete than observations. Repeat observations lead to facts. Facts get stronger and stronger with more repeat observations. If you only saw the moon once in your life, you couldn’t exclaim “the moon exists- fact!”. We can claim that the moon exists as a fact, because it has stood the test of repeat observations. We went as far as walking on it, just to make sure.

It is a fact that the climate of our planet is changing. “Climate change”, to use the jargon, is a factually accurate statement. (See my earlier blog on this, for a more detailed explanation).

What are facts used for?

Facts are only useful if they help us understand something about the world. They need a context. We use facts to help us answer questions. But let us be incredibly clear about one thing: there is no such thing as “alternative facts”. There are alternative questions. It is often incredibly difficult to match facts to the right question. Politicians are particularly bad at this. Some scientists are bad at this too, which is why an integral part of science is to ask whether the data collected matches the question asked.

What is the difference between a theory, a hypothesis and a law?

A hypothesis is what you start with, in order to eventually arrive at a theory. It is to theory, what an observation is to a fact. It proposes an explanation for the observations. Hypotheses are daring! They are flamboyant and live and die on the edge. They propose an explanation for observations and they can either stand up straight or fall completely flat on their face. Falsification is more robust than verification. When something is not true, it is most definitely so. But when something stands to reason, there is always a small chance that it might not end up being true, in the long term. In other words, it is harder to be right than to be wrong.

Hypotheses are the racehorses of science. They are the sprinters and long distance runners. They are the prize fighters, and they take a mighty battering. One hypothesis against another, over and over and over again. And out of the strongest hypotheses emerge unifying theories that propose to explain a set of facts. Theories are grander than hypotheses, but they are subject to the same rules of logic. If they are trying to prove something right, they are inevitably opening themselves to argument. But they are stronger than hypotheses, because they stand on the shoulders of the strongest of these. There are always alternative hypotheses and alternative theories. That is what they are for. They exist to battle it out.

The best ones always win, because they attract more facts to support them. Alternative interpretations are not all equally valid. There are winners and losers based on objective metrics. And once a theory is flat on its face, it stays there, on the floor.

Laws are theories that have made it past a certain point of doubt. They are, by definition, unfalcifiable. In science, if you can produce a counter example to a law, it is no longer a law. Biologists do not tend to believe in laws within their domain of science. That is because each biological system is so complex, and stochasticity (random chance) plays such a significant part in the problem. Biologists embrace an element of chaos. Physics is more proficient in the language of laws. That doesn’t mean that biologists have more reason to doubt their theories. It is simply that the language of laws doesn’t enable progress in our branch of science. It is not useful.

At what point do facts become the truth?

Scientists do not use the language of “truth”. Even physicists use the language of “laws”, instead of speaking about truth. Asking at what point do facts become the truth is like asking, when do apples become oranges? A fact is a fact is a fact is a fact. There are no alternative facts in science, and we do not use the word truth. Ever. Science is colder than “truth”, which is subjective and impassioned. Another way of thinking about truth is by considering its opposite. Lying. Lying is knowingly distorting the observations. Lying requires knowledge of the truth, and then its distortion. In that respect, “truth” is closer to observation than it is to facts. Truth is a low bar to science, we are much more content with gathering facts and sorting through our alternative hypotheses.