Why does 2 + 2 = 4? (Hint: The answer may surprise you!)

Everyone knows that arithmetic is true. Our entire world depends on it, from the money in our bank accounts to every economic transaction we make. Arithmetic is also the foundation of the mathematics that underpins science and technology.

Yet, remarkably, we don't know why we know this. In this talk, Randolph will show how certainty that arithmetic is true has created a cognitive blind spot, preventing us from asking deeper questions. After removing that blind spot, we'll search for the cognitive origins of numbers and arithmetic, from ancient Greek philosophy to insect navigation, and from perceptual psychology to meta-mathematics.

Along the way, we'll see how mathematics is reborn in a child's mind, why it is a "mirror of symbols" that is both discovered and invented, and why, in Galileo's words, "mathematics is the language with which God has written the universe".

Bio

Randolph Grace is Professor of Psychology at the University of Canterbury, where he leads an interdisciplinary research group on mathematical and spatial cognition. He holds a BSc in Electrical Engineering & Computer Science from MIT and a PhD in Psychology from the University of New Hampshire. He has published widely in a variety of research areas including mathematical psychology, comparative cognition, behaviour analysis, experimental psychology, forensic psychology, behavioural economics, cognitive neuropsychology, and statistics/methodology. He currently serves on the Marsden Fund Council for Royal Society Te Apārangi.

Event

Tuesday, 15 September 2026, 6:30pm – 7:30pm @Botanic,

The other talk at this location is ………. at 8:00pm – 9:00pm