In his study The Rise of Professional Society historian Harold Perkin characterizes professional society; "Where pre-industrial society was based on passive property in land and industrial society on actively managed capital, professional society is based on human capital created by education and enhanced by strategies of closure, that is, the exclusion of the unqualified." Specifically, it is the management of human capital, and not just specialized skill which Perkin argues is a mark of the professional classes, at one point going so far as to compare it to a modern form of feudalism.

Although professional training appears to be ideologically neutral, it may be biased towards those with higher class backgrounds and a formal education. In his 2000 book, Disciplined Minds: A Critical Look at Salaried Professionals and the Soul-Battering System that Shapes Their Lives, Jeff Schmidt observes that qualified professionals are less creative and diverse in their opinions and habits than non-professionals, which he attributes to the subtle indoctrination and filtering which accompanies the process of professional training. His evidence is both qualitative and quantitative, including professional examinations, industry statistics and personal accounts of trainees and professionals.

A key theoretical dispute arises from the observation that established professions (e.g. lawyers, medical doctors, accountants, architects, civil engineers, surveyors) are subject to strict codes of conduct. Some have thus argued that these codes of conduct, agreed upon and maintained through widely recognized professional associations, are a key element of what constitutes any profession. Others have argued that strict codes of conduct and the professional associations that maintain them are merely a consequence of 'successful' professionalization, rather than an intrinsic element of the definition of professional (ism); this implies that a profession arises from the alignment between a shared purpose (connected to a 'greater good'), a body of knowledge, actual behavior in terms of actions and decisions, and expectations held by societal stakeholders.

The etymology and historical meaning of the term professional is from Middle English, from profes, adjective, having professed one's vows, from Anglo-French, from Late Latin professus, from Latin, past participle of profitēri to profess, confess, from pro- before + fatēri to acknowledge; in other senses, from Latin professus, past participle. Thus, as people became more and more specialized in their trade, they began to 'profess' their skill to others, and 'vow' to perform their trade to the highest known standard. With a reputation to uphold, trusted workers of a society who have a specific trade are considered professionals. Ironically, the usage of the word 'profess' declined from the late 1800s to the 1950s, just as the term 'professional' was gaining popularity from 1900 to 2010. Notably, in American English the rise in popularity of the term 'professional' started at the beginning of the 20th century whereas in British English it started in the 1930s and grew fastest in the 1960s and 1970s.

The notion of a professional can be traced to medieval European guilds, most of which died off by the middle of the nineteenth century, except the scholars guild or university.

With most guilds formally abolished outside of the realm of academia, establishing exclusivity and standards in a trade (i.e. the successful professionalization of a trade) had to be achieved via other means such as licensing practices, of which might begin as an informal process established by voluntary professional associations, but then eventually become law due to lobbying efforts. Paralleling or soon after the fall of guilds, professional associations began to form in Britain and the US. In the US, several interested parties sought to emulate the model of apprenticeship that European guilds of the Middle Ages had honed to achieve their ends of establishing exclusivity in trades as well as the English concept of a gentleman which had come to be associated with higher income and craftsmanship. Examples are the Lazzaroni who lobbied to create the American Association for the Advancement of Science (AAAS) and professional associations who lobbied to create the American Medical Association (AMA). According to Miller et al., "Lazzaroni opposed reforms for no apparent reason other than that scientists outside of their tight-knit group proposed them.". In his seminal work The Transformation of American Medicine (1982) Paul Starr argues that a significant motivation in the development of the AMA was to gain authority over unlicensed practitioners to minimize competition among medical practitioners, thereby enhancing the earning power and prestige of medical professionals. The licensing process Starr argues, was unnecessarily prolonged and the costs were artificially enhanced with the specific aim of deterring potential practitioners from entering the field. In his book, The Early Development of Medical Licensing Laws in the United States, 1875–1900, Ronald Hamowy wrote:

"The American Medical Association (AMA) was established as a permanent national organization at Philadelphia in 1847 at a convention attended by some 230 delegates representing more than forty medical societies and twenty-eight schools. From its inception, one of its primary aims was upgrading medical education and a concomitant reduction in the number of physicians. Its committee on raising medical standards reported at its first meeting that "the large number of Medical Colleges throughout the country, and the facility with which the degree is obtained, have exerted a most pernicious influence" on the profession. With the object of alleviating this situation, recommendations were carried out calling for a specified minimum preliminary education as a prerequisite for admission to a medical college, a lengthening of the period of study for graduation from a medical school, including compulsory clinical instruction at a hospital before the issuance of a diploma, and professional participation in some licensing scheme for physicians. Indeed, the issue of education was considered so important by the AMA that one of its first acts was the establishment of a Committee on Medical Education..."

As technology progressed throughout the twentieth century, the successful professionalization of a given field was increasingly made possible through the idea of specialization.

As …

Read more on Wikipedia