WHEN the autonomous cars in Isaac Asimov's 1953 short story “Sally” encourage a robotic bus to dole out some rough justice to an unscrupulous businessman, the reader is to believe that the bus has contravened Asimov's first law of robotics, which states that “a robot may not injure a human being or, through inaction, allow a human being to come to harm”. Asimov's "three laws" are a bit of science-fiction firmament that have escaped into the wider consciousness, often taken to be a serious basis for robot governance. But robots of the classic sort, and bionic technologies that enhance or become part of humans, raise many thorny legal, ethical and regulatory questions. If an assistive exoskeleton is implicated in a death, who is at fault? If a brain-computer interface is used to communicate with someone in a vegetative state, are those messages legally binding? Can someone opt to replace their healthy limbs with robotic prostheses?

Questions such as these are difficult to anticipate. The concern for policymakers is creating a regulatory and legal environment that is broad enough to maintain legal and ethical norms but is not so proscriptive as to hamper innovation. It was with this difficult mission in mind that the €1.9m ($2.4m) RoboLaw consortium of experts in law, engineering, philosophy, regulation and human enhancement was brought together in 2012.

On September 22nd the consortium released the results of its deliberations: the "Guidelines on Regulating Robotics". On September 24th they were presented at a session on legal affairs at the European Parliament (the European Commission footed €1.4m of the project's bill). The document is a set of recommendations designed to help European legislators successfully manage the introduction of new robotic and human enhancement technologies into society without compromising principles already enshrined in European law.

The report's authors warn against “excessively restrictive” legislation that can stifle innovation, recommending a “functional perspective” that focuses on practical effects and incentives embodied in any new robot-specific laws. An approach to broad, over-arching robot legislation—such as Asimov's "three laws of robotics"—is likely to fail, says Andrea Bertolini, of the Scuola Superiore Sant’Anna, in Pisa, Italy, which led the consortium. Instead, ad hoc legislation could be used to steer the development of the market in specific directions. That is an important suggestion when the term "robot" covers such a diversity of devices, from medical robots to vacuum cleaners to prostheses.

Stringent product-safety rules, for example, might discourage development of advanced prostheses and exoskeletons, a set of technologies that the European Union is keen to support, given its legal and policy commitment to disability rights. Liability exemptions for manufacturers could relieve some pressure. “No-fault” plans, especially in cases where an insurance market for robotic devices is difficult to establish, could help too. Manufacturers and governments could pay into a compensation fund used if mishaps occur.

Prostheses also raise questions around the legal distinction between person and property, but the report suggests that there is no advantage to creating a new category between human and machine. As Dr Bertolini puts it: “a human with a prosthesis is still a human.” But what of rights for the machines themselves? Dr Bertolini says that there are several arguments against granting them. Firstly, artificial intelligence is still far from surpassing that of humans. More philosophically, any autonomy that robots gain is designed and granted by humans. Thus, the argument goes, robots are to be considered objects, not subjects; the question of rights then disappears. On the other hand, the report says that in limited circumstances, robots might be granted a legal status similar to a corporation, perhaps enabling robots to perform legal transactions (but raises the question of how a robot can be legally represented in court).

The authors call for the role of supranational bodies such as the International Standardization Organization to be strengthened, and suggest that an international body to regulate robotic devices may be required—many of the questions posed will become inherently international concerns. But Ryan Calo, a law professor at the University of Washington, says that America lags behind both Europe and Asia in its attempts to tackle these ethical, regulatory and legal issues. Mr Calo recently called for the establishment of a Federal Robotics Commission to coordinate the piecemeal research going on in America. In the meantime, he says, the RoboLaw guidelines will be some help.

The original charter of RoboLaw had it that its flagship report would be a more high-profile European Commission white paper; instead it has become a policy discussion document. Nevertheless, it sparked significant debate among the MEPs in the session, in some cases around the very issues that the report means to flag up. Whether or not the commission takes up the task pre-emptively, these technologies will outstrip the ability of existing legal frameworks to govern them.

Asimov's "three laws of robotics" sparked imaginations about how robots could be governed. But they were merely a literary device; they can now, respectfully, be laid to rest as the basis for serious legal discussion. The truth is stranger, and more complex, than fiction.