One of my earliest posts here concerned the definition of play, which I developed further in an article on “Definitions of Play” for Scholarpedia (Gray, 2013) and in my book Free to Learn. I first ...

Asking a biologist to define 'life' is a bit like looking-up the word 'definition' in a dictionary — it's as if you're questioning their very existence. Biologists like myself don't agree on what life ...