"All Cretans are liars", said Epimenides, a Cretan. But this means that his statement must be a lie too. But then it is false that Cretans are liars and the statement must be true. So what now?

I teach people how to teach math, and I’ve been working in this field for 30 years. Across those decades, I’ve met many people who suffer from varying degrees of math trauma – a form of debilitating ...