Editing The Blind Watchmaker (section)

== Synopsis ==
[[file:BiomorphBounce.png|thumb|left|"Biomorph" that randomly evolves following changes of several numeric "genes", determining its shape; the gene values are given as bars on the top]]

The title of the book refers to the [[watchmaker analogy]] made famous by [[William Paley]] in his 1802 book ''[[Natural Theology or Evidences of the Existence and Attributes of the Deity]]''.<ref name="Radford"/> Paley, writing long before [[Charles Darwin]] published ''[[On the Origin of Species]]'' in 1859, held that the complexity of living organisms was evidence of the existence of a [[divine creator]] by drawing a parallel with the way in which the existence of a watch compels belief in an intelligent watchmaker. Dawkins, in contrasting the differences between human design and its potential for planning with the workings of natural selection, therefore dubbed evolutionary processes as analogous to a blind watchmaker.

To dispel the idea that complexity cannot arise without the intervention of a "creator", Dawkins uses the example of the eye. Beginning with a simple organism, capable only of distinguishing between light and dark, in only the crudest fashion, he takes the reader through a series of minor modifications, which build in sophistication until we arrive at the elegant and complex mammalian eye. In making this journey, he points to several creatures whose various seeing apparatus are, whilst still useful, living examples of intermediate levels of complexity.

In developing his argument that natural selection can explain the complex adaptations of organisms, Dawkins' first concern is to illustrate the difference between the potential for the development of complexity as a result of pure randomness, as opposed to that of randomness coupled with cumulative selection. He demonstrates this by the example of the [[weasel program]]. Dawkins then describes his experiences with a more sophisticated [[computer simulation]] of artificial selection implemented in a program also called ''The Blind Watchmaker'', which was sold separately as a teaching aid.

The program displayed a two-dimensional shape (a "biomorph") made up of straight black lines, the length, position, and angle of which were defined by a simple set of rules and instructions (analogous to a genome). Adding new lines (or removing them) based on these rules offered a discrete set of possible new shapes (mutations), which were displayed on screen so that the user could choose between them. The chosen mutation would then be the basis for another generation of biomorph mutants to be chosen from, and so on. Thus, the user, by selection, could steer the evolution of biomorphs. This process often produced images which were reminiscent of real organisms for instance [[beetle]]s, [[bat]]s, or [[tree]]s. Dawkins speculated that the unnatural selection role played by the user in this program could be replaced by a more natural agent if, for example, colourful biomorphs could be selected by butterflies or other insects, via a touch-sensitive display set up in a garden.

In an appendix to the 1996 edition of the book, Dawkins explains how his experiences with computer models led him to a greater appreciation of the role of [[developmental biology|embryological]] constraints on natural selection. In particular, he recognised that certain patterns of embryological development could lead to the success of a related ''group'' of species in filling varied ecological niches, though he emphasised that this should not be confused with [[group selection]]. He dubbed this insight ''the evolution of evolvability''.

After arguing that evolution is capable of explaining the origin of complexity, near the end of the book Dawkins uses this to argue against the existence of God: "a deity capable of engineering all the organized complexity in the world, either instantaneously or by guiding evolution ... must already have been vastly complex in the first place ..." He calls this "postulating organized complexity without offering an explanation".

In the preface, Dawkins states that he wrote the book "to persuade the reader, not just that the Darwinian world-view ''happens'' to be true, but that it is the only known theory that ''could'', in principle, solve the mystery of our existence".