“Should engineers think?” That question, at first glance mildly insulting to the profession, crops up early in a recent volume of Interdisciplinary Science Reviews devoted to 'Philosophy and Engineering' (33(3), 2008). But as Natasha McCarthy of the UK's Royal Academy of Engineering points out in her editorial introduction, “The stereotype tells us that engineers are 'doers' and not 'thinkers'.”

Leaving aside the flaws in the notion of sharp boundaries between scientists (the 'thinkers') and engineers, the message is clear: engineers have a job to do, and 'philosophy' is rarely seen as relevant to it. But beyond thinking about the technical aspects of the task, should engineers consider matters of cost, safety, risk, environmental, social, ethical and aesthetic impacts? If they don't, should this be seen as a form of engineering failure?

Of course, few engineering jobs don't explicitly embrace some of these concerns. Many materials, for example, are developed specifically to improve safety or to reduce harm to the environment. But even then, the issues are not always straightforward. A biodegradable product can't be assumed to be 'greener' without a life-cycle analysis that might lie beyond the expertise of the product designers. No one foresaw, or could be expected to foresee, or even now agrees on, the social impact of automobiles, computers and mobile phones.

But truly to engage with some of these matters, or even to make seemingly routine assessments of risk and safety, might require that engineers acknowledge a genuinely philosophical dimension of the profession, particularly in the sphere of epistemology, or as McCarthy puts it, what we know and how we know what we know. Partly this is a question of how one obtains reliable information. But there has been increasing recognition that it also bears on what is knowable. Some complex engineered systems show emergent phenomena that can't be predicted, even in principle, from knowledge of the components. Dealing with that challenge is considered here by W. P. S. Dias of the University of Moratuwa in Sri Lanka, and by Darryl Farber and colleagues at Pennsylvania State University. A related difficulty tackled by the latter group is how to meaningfully forecast performance in the face of incomplete knowledge about what the system will encounter.

Epistemology aside, much of engineering philosophy might be considered to encompass ethics. Here McCarthy takes a stance: an engineer cannot be expected to reflect on aspects beyond the call of duty, which basically means getting the job done efficiently, effectively and safely. Indeed, it might be dangerous to do so without the necessary expertise. But that, she says, doesn't absolve engineers of moral obligations — for they have a duty to ensure that such broader issues have been given due thought by others suitably qualified.

This sound principle might quickly become a minefield in practice. How can engineers assure themselves that this process has been carried out, and done well? How is the obligation enforced? (Clearly, it isn't.) In this and other ways, this volume is just the start of the discussion.