Introduction

My brief historical overview in Chapter 1 alluded to the crucial influence of the Newtonian mechanistic picture on the development of our view of the Universe. According to this, the cosmos operates likes a giant machine, oblivious to whether life or any form of consciousness is present, i.e. the laws of physics and the characteristics of the Universe are independent of whether anybody actually observes them. In the last fifty years, however, the Anthropic Principle has developed [1], and this might be regarded as a reaction to the mechanistic view. This claims that, in some respects, the Universe has to be the way that it is because otherwise it could not produce life and we would not be here speculating about it. Although the term ‘anthropic’ derives from the Greek word for ‘man’, it should be stressed that most of the arguments pertain to life in general.

As a simple example of an anthropic argument, consider the following question: why is the Universe as big as it is? The mechanistic answer is that, at any particular time, the size of the observable Universe is the distance travelled by light since the Big Bang, which is about 1010 light-years. There is no compelling reason the Universe has the size it does; it just happens to be 1010 y old.