learned. Any craft or trade has its discipline—as do many activities that are not craft or trade, such as meditation or calisthenics. In this sense, neither architects, nor industrial designers, nor weekend inventors are engineers. Architecture and industrial design each have a discipline easily distinguished from engineering’s. Weekend inventors have no discipline at all; they may invent any way they like.

Software engineering is not engineering in this third sense. The body of knowledge engineers are supposed to learn differs in important ways from software engineering’s body of knowledge. So, for example, engineers have to take courses concerned with the material world, such as chemistry and statistics; software engineers do not. Software engineering’s official Body

IllustratIon by hanK osuna

software engineering
has, indeed, become a
profession. What it has
not become is part
of the engineering
profession.

of Knowledge was in fact an important step in clarifying the distinction between engineering proper and software engineering. It requires software engineers to know things other engineers do not and not to know some things other engineers do know.

The last sense of engineering we need to distinguish here is engineer-ing-as-profession. A profession is (we may say) a number of individuals in the same occupation voluntarily organized to earn a living by openly serving a moral ideal in a morally permissible way beyond what law, market, morality, and public opinion would otherwise require.a An occupation is a discipline by which one may, and some do, earn a living. Both engineering and software engineering are now occupations but, having (as just noted) different disciplines, must be different occupations. That is one reason why they cannot share a profession. There is another.

The Software Engineering Code of Ethics and Professional Practice differs in significant ways from all the engineering codes I know. Software engineers are, for example, supposed to “[m]oderate the interests of the software engineer, the employer, the client and the users with the public good” a For a defense of this definition, see my article “Is Engineering a Profession Everywhere?”

( 1.02).b Engineers do not now have such a duty to moderate.

Software engineering has, indeed, become a profession. What it has not become is part of the engineering profession. Anyone who claims otherwise must find a sense of engineering different from those distinguished here, one that makes software engineering a part of engineering without including as well disciplines, occupations, or professions, such as architecture or accounting, that clearly are not part of engineering.

Professions are voluntary associations. You cannot become a member simply by claiming to be one. You must be admitted (by the profession, not just by a technical society like the ACM). Engineering has a long history of other occupations claiming to be engineering: recent examples include genetic engineering (a kind of tinkering with genes); reengineering (a fad in management); and financial engineering (gambling on Wall Street). Software engineering actually began with an attempt to copy engineering practices, making its claim to be engineering more respectable b Software Engineering Code of Ethics and Professional Practice (1999); http://www.acm.org/ about/se-code. For history of this document, see my essay “Code Writing: How Software Engineering Became a Profession,” Center for the Study of Ethics in the Professions, Chicago, 2007; http://hum.iit.edu:8080/aire/sea/1/ book/ index.html.