Should we, technologically, always do what we can do? Does openness to technology always mean to do whatever is feasible? This paper argues for discourse ethics within science and technology. The future of industrial societies depends not least on technical developments in science, technology, and engineering. However, the social and ethical responsibility that arises from these developments is not systematically reflected within the disciplines. Ethical questions are hardly ever raised, let alone answered, in engineering curricula or technical studies. Where will the development of what is technically feasible lead us if the responsible engineers lack a basic ethical understanding? Motivated by the remembrance of ethical misconduct of engineers in the Third Reich, the article seeks to underpin the need for an applied ethics for engineers, technicians and natural scientists with a historical and systematic explication of the ethics discourse in classical rhetoric and the history of philosophy. Under the impression of current developments in the digitalised media society and the connection between ethos (ἦθος) and language, the paper pleads for a discourse-ethical approach and seeks to make this fruitful for the fields of application mentioned. Against the background of current research on technology impact, the article ends with a look at some classical examples of the literary depiction of ethical dilemmas in technical solutions, hoping to stimulate further reading in the arts and sciences.