**Counting the infinite**.**Adam:**Hello Plato, sorry I was busy in Friday, care for another chat about infinity?

**Plato:**Definitely, let's see. Last time we decided that a set is a collection of some number of objects, that can be thought of as a box. We also said it makes sense to say that an infinite set cannot be given a number as its size. But I said that we had missed something and wanted to know how we could say the size of something infinite.