Serious philosophy with a smile. The world seems to be full of people who know things. Wherever you turn, there are those who are absolutely sure of this, positive about that, or certain that such and such is the case. There are scientists who tell us they have demonstrated that something is true. There are mathematicians who say they have proved some theorem or other. There are religious people who are certain that god exists, and that they know for sure what He wants Us to do. And, down the pub, there are those who definitely know what simple thing needs doing about any and every seemingly...