I like the number four, so I've decided to devote this chapter to one of my favourite subjects: Philosophy. Throughout this chapter I will introduce six or seven (to fit in with the chaptering scheme, depending on how I decide to close the chapter) philosophical ideas, expand on each of them in turn, and then throw them open for discussion.

Of course, if you haven't even a passing interest in philosophy, you can think of this chapter as a nice long commercial break, during which you can boil up the kettle as many times as you like (making sure to bear in mind global warming, and not put too much of a load on the national grid - boiling up the kettle after all requires a substantial amount of electricity), and then when we leave this fourth chapter and enter the fifth, you can be sure to have enough caffeine inside you to keep you awake and alert to peruse the contents of the latter mentioned.

Alternatively, if you are one of those curious people who defies convention and categorisation, you will find herein a selection of the most delectable goodies, to tickle your brain and stimulate your fancies beyond your wildest dreams. So, make yourself comfortable, and make sure you get the sleep you need to exert your imagination to its fullest capacity in our discussions, and let's make this something to remember.

So we'll begin our Philosophical Discussion with...