In the law and economics literature liability is generally regarded as an instrument which provides potential tortfeasors with incentives for optimal care taking. The question, however, arises whether liability can still provide those incentives when risks are unknown. That is the central question that is addressed in this contribution. One may, furthermore, have to differentiate between risks that are unknown to the tortfeasor and those are that not known according to the state of the art. After setting out the economic functions of liability rules and regulation the effects of missing information for care levels and activity levels is sketched and attention is paid to the way in which strict liability and negligence affect the incentives to conduct research concerning unknown risks. We conclude that an exposure to liability may on the one hand provide potential tortfeasors with incentives to do further research and hence to innovate; on the other hand, liability for unknown risks could also limit activity levels of socially desirable activities. We therefore conclude that it remains inherently difficult to use tort law as an instrument to provide incentives to generate information concerning unknown risks. We argue that in the tradeoff between tort liability and safety regulation there are strong arguments in favour of safety regulation, on the condition that it is used in a smart mix with liability rules. Finally we equally investigate problems that arise in case of insurance of liability for unknown risks.