120 D. Koepsell double the yield of a hydrogen bomb. As your euphoria subsides, you begin to ponder the consequences of this breakthrough, and realize its narrow range of use, limited only to offensive thermonuclear weapons. You also realize its discovery by others is eventually inevitable, although perhaps at best 5 years off. Or perhaps you’re a geneticist, and you’ve ﬁgured out that a clever bit of splicing can turn a certain virus into an even more lethal form. The process is scientiﬁcally easy to do, aesthetically elegant, and the result terrifying. A plague that might have stuck down one in ten people in its natural form would become deadly to nine out of ten. Moreover, a vaccine would be difﬁcult to develop. You ponder the implications, and consider whether you should move forward with experiments and eventual publication. Or ﬁnally, you are a nanotech researcher, trying to wed computing with materials. Your dream is to create molecule-sized robots that will do our bidding, constructing items atom-by-atom, capable of user-generated, customized alterations, and fully recyclable. As you near your goal, you realized the full potential of your new creation, which could just as easily disassemble a human being as construct a cup. You consider not only whether and how evil uses of this breakthrough technology might be prevented, but also whether the potential harms outweigh all potential beneﬁts. These are not merely academic hypotheticals, but rather accounts of actual events and dilemmas, both past and present. This paper will consider some historical events, and the ethical quandaries posed by each to real-world researchers. Usually, when discussing the moral implications of various technologies and sciences, we take for granted certain presuppositions, such as: ‘‘we can’t put the genie back in the bottle,’’ and that ethics is the realm of technologists, not scientists, since scientists have a duty to explore all questions, but technologists have no duty to release every technology. Is it conceivable that these presuppositions are erroneous? Do scientists have duties, regarding especially dangerous aspects of nature, NOT to pursue certain ﬁelds of research? Do they share responsibility with technologists who eventually release dangerous technologies? Does this responsibility involve moral culpability whether or not there are any harms that result? These questions and assumptions deserve a second look. They were the focus of a number of thinkers, including scientists such as Einstein and Oppenheimer, at the beginning of the nuclear age when scientists who had been involved in the development of nuclear weaponry came to oppose the tools they had helped develop. It’s an age-old angst, borne in the Frankenstein tale, involving the inevitable clash of unbounded, unfettered scientiﬁc exploration and deadly consequences that sometimes result. Too often, scientists have plodded or lunged along, investigating new means of engineering more destructive technologies, insulated by the concept that science should never be stiﬂed, and that liability for the tools eventually developed because of their investigations rests solely on technologists, engineers, and politicians. But what justiﬁes the disavowal of moral culpability by those in the best position to reveal new and deadly aspects of nature? Is there any moral duty on the part of individual scientists to simply say ‘‘no’’ to investigating those things whose only or best uses are to cause harms? 123