In some cases, relinquishing certain domains of technological development is not possible, since the research and development of a particular technology is based on an existing body of knowledge that is too complicated to effectively turn back the clock on. Additionally, it is not always possible to predict the potential benefits or drawbacks of a particular technology before it is developed, so pre-emptive relinquishment could lead to missed opportunities. Finally, technological development is often driven by a variety of external factors such as economic demands and public interests, which can make it difficult to effectively control the development of a given technology.