ABSTRACT
Imagine you see before you two young children on a beach. They have spades in their hands and there are small buckets in the immediate vicinity. They have built a sandcastle with two outer walls, the first of which is gradually disappearing under the oncoming tide. There is much consternation and many shrieks from one child, although the other seems much more stoical, even relishing the situation. What do you think they’re doing? They could be doing a number of things, including witnessing the imminent collapse of civilisation as we know it, but whatever it is, it has probably involved imaginary and co-operative play.
