It is hard to shake the intuition that there's a real and objective physical world out there. If I see an umbrella on top of a shelf, I assume you do too. And if I don't look at the umbrella, I expect it to remain there as long as nobody steals it. But the theory of quantum mechanics, which governs the micro-world of atoms and particles, threatens this commonsense view.

Featuring Chiara Marletto, Research Fellow of Physics, and Christopher Timpson, Professor of Philosophy of Physics, both at the University of Oxford, and Marcus Huber, Professor of Physics, TU Wien.

This episode is presented by Miriam Frankel and produced by Hannah Fisher. Executive producers are Jo Adetunji and Gemma Ware. Social media and platform production by Alice Mason, sound design by Eloise Stevens and music by Neeta Sarl. A transcript is available here. Sign up here for a free daily newsletter from The Conversation.

Further reading: 

• 'QBism': quantum mechanics is not an objective description of reality – it reveals a world of genuine free will