It is a common thought that classical, Newtonian physics presents us with an intuitive, easy-to-understand picture of what reality is really like, which follows unproblematically from the mathematical equations: point-like particles flying around in a rigid 3d container. If we know the container’s precise state at some point in time, Newton’s laws of motion and his universal gravitation tell us exactly where the particles will be at any other point in time. This intuitiveness and easy understanding come to an abrupt end early in the 20th century. Einstein’s relativity maims Newton’s neat concepts of space and time and we’re no longer sure which clocks are synchronous and which rulers are straight. Physics has become abstract and unintuitive so that it is now unintelligible for anyone untrained in higher mathematics.

In my lecture (based on my [Dutch] book) I argue that this is misrepresents the situation. I will show that the problems and concepts that make Einstein’s relativity so difficult to understand (the nature of space and time, locality and determinism, to name but a few) are also problems and concepts that underlie Newtonian physics: they must be faced by anyone who wishes to get from physics’ experimental outcomes to a view of reality.

On the bright side, the fact that the same philosophical issues play a role in both classical and modern physics means that once we really get to grips with the foundational issues underlying classical physics, we automatically gain a much better understanding of modern physics – physics without philosophy is blind.

Philosopher of physics at Amsterdam University College and Utrecht University, managing editor for Foundations of Physics and international paraclimbing athlete