Paul Davies

Foreword

By Edo Segal

The number that stopped me was not about intelligence. It was about emptiness.

One part in ten to the power of one hundred and twenty. That is the precision with which the cosmological constant — the energy density of empty space itself — must be calibrated for a universe that permits galaxies, stars, planets, chemistry, biology, and minds. Not approximately calibrated. Calibrated to a precision that makes the word "precision" feel inadequate, like calling the Pacific Ocean damp.

I encountered this number in Davies's work while deep in the rabbit hole of writing *You On AI*, and it would not leave me alone. I carry large numbers in my head the way other builders carry deadlines — as constraints that define the shape of what is possible.