Understanding the difference between theory and fact in science is an important step in understanding the way that scientists communicate. In science, the word ‘fact’ isn’t something that gets thrown around very often. On the other hand, the word ‘theory’ gets attached to some of the most foundational concepts in science. Why is this the case?

The way that science is carried out, involves the generation of theories. A theory is essentially an educated ‘best guess’, whereby observations and data are interpreted.

Let’s use an example.

If you throw a ball off the top of a building, it will fall. This is the observation. To make the experiment robust, you might also throw a pen, a carton of milk, a book, an apple and a screw driver. All of these items behave in the same way as the ball. Therefore the conclusion is, if you throw something off a building, it will fall.

The next step in science, is to provide an interpretation of the data that you have generated. It was after seeing an apple fall from a tree that Isaac Newton developed his theory of gravity. Newton used the idea of gravity to explain why objects are drawn towards the ground.

In science, the term ‘theory’ is used to describe conclusions in science. A theory is considered robust if it has not been disproved. The term theory doesn’t insinuate that the conclusion is wrong, it is simply the best explanation that we have.

The term theory includes in it a degree of uncertainty that must be had in science. We can’t prove the existence of gravity, we can only point to observations of its existence. Therefore, there is a degree of uncertainty as to the existence of gravity. It’s possible that everything is tied to the Earth with invisible string, and gravity doesn’t exist at all. But the lack of observations for the ‘invisible string’ theory makes it seem fairly ridiculous. However, since there does remain uncertainty as to the existence of gravity, it can only be known as a theory.

As more observations are made that support a theory, that theory becomes more robust and widely called upon.