Gravity is ‘just’ a theory

If you drop something – say an apple – it will fall right? But how do you know that it will fall? In fact, you don’t actually know that it will fall – but every other time you dropped something it fell, so you are pretty sure that this time the apple will fall too.

This is a (very) simplistic example of how humans have been gaining knowledge for thousands of years. Basically we follow a simple process:

  1. We observe things in the world around us. Every time I drop something, it falls to the ground.
  2. We propose a hypothesis explaining what we see. I propose that every time I drop something it will fall. (As an aside this is not the theory of gravity*)
  3. We make predictions according to the hypothesis. I predict that every time I drop something… down it will go.
  4. We use the predictions to create and repeat experiments. Drop a bunch of things to check that our prediction holds.

One day we could disprove the theory by dropping something that doesn’t fall. But, no matter how many experiments we conduct, we can never prove our theory. We just amass a lot of evidence that we are right, but the point is our idea remains a theory. It could be proven wrong at any time.

Evolution is also ‘just a theory’ – but so is gravity, and our theory about dropping things. And like gravity, evolution has a HUGE amount of evidence behind it. Don’t dump it because it’s just a theory – otherwise you should be dumping everything that humans have learned over the last 13,000 years!

* The theory of gravity, at a very simple level, states:

  • Any two objects will attract each other. For example the earth exerts a force of attraction on you – and you exert a force of attraction on the earth.
  • The force of that attractions is proportional to the mass (size) of the objects. The earth is really massive so the force between you is enough to hold you down!