Check out the physics courses that I mentioned (many of which are free!) and support this channel by going to https://brilliant.org/Sabine/ where you can create your Brilliant account. The first 200 will get 20% off the annual premium subscription. What is space-time? What is a particle? I get these questions a lot. My best answer is "math". But does this mean that mathematics is real? Are we maybe even made of math? Or could it even be, as Max Tegmark has argued in his "mathematical universe Hypothesis", that all of math is real? In this video I go through what we know and what we don't know. Correction to what I say at 4 mins 7 seconds: That should have been "irreducible representations of the Poincare group". 0:00 Intro 0:25 Which math is real? 2:52 Are particles and space-time real? 4:19 Is there more to reality than math? 5:20 Is all math real? 7:56 Sponsor message #physics #mathematics #philosophy