One of mankind's major skills is the ability to construct and use tools. The silex tools of the stone age have now become complex machines - computers - and we rely more and more on them. It is therefore not surprising that robots and automated machines are omnipresent in the societies of the future imagined by science-fiction writers. This is especially true when the topic of their stories is the exploration and colonization of space.

In many science-fiction novels, the colonization of space by mankind is prepared for by the systematic exploration of stellar systems with automated probes. The most impressive way to conduct this exploration is to use automated, auto-reproducing machines called Von Neumann machines. The idea, present in the novel "The Time Ships" by Stephen Baxter, is to build and send towards the stars a single machine that will be able, once it has arrived at its destination, to start building replicas of itself (at least two) and send them towards other stars (like a computer virus which, once it has infected a machine, will send copies of itself using electronic mail!). Once started, the process will quickly expand. If each machine builds two replicas of itself and sends them to explore other stellar systems where they will also duplicate themselves, the number of stellar systems explored after n generations is roughly 2ⁿ. After ten generations, more than one thousand stellar systems would have been explored and prepared for colonization, whilst after twenty generations this number would reach 1 million. The whole galaxy would be conquered after only thirty to forty generations of machines!

The ultimate stage of automated machines is artificial intelligence (AI). Wild AIs tend to be presented as a threat to mankind. As an example, in the novels of Gregory Benford, starting with "Great Sky River", mechanical AIs form a complete, independent order of life (the fifth one) and are actively fighting the biological civilisations for supremacy in the Universe. And, as far as mankind is concerned, the balance is in favour of the AIs which it may have originally created. In this context, it is impossible to avoid the three laws of robotics imagined by Isaac Asimov. Their goal is to make sure that intelligent or semi-intelligent robots will never hurt or be used to hurt human beings. The three laws are: first, a robot will not hurt a human being, or by remaining passive allow a human-being to be hurt; second, a robot must obey orders given by a human being, except if these orders are in conflict with the first law; and third, a robot must protect itself as long as this protection does not conflict with the first or second laws. In his long series of novels and short stories, Isaac Asimov has explored all the consequences of these laws, as well as their possible flaws.

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