Historically, the Enlightenment or the Age of Reason is not confined to a specific period of time. Arguably, the era extends from the late seventeenth century to the early nineteenth century. However, it is the eighteenth century that receives most of the historical focus because of the great thinkers of the age who had a profound impact on the future of the world.

The traditional approach to understanding the Enlightenment period is to select important figures in the fields of science, politics, and philosophy and examine their contributions or to study historical incidents to determine their significance to the era. Since the movement began in Europe, the tendency is to search for a single unified way of thinking that sufficiently defines the age. Europeans were not, however, unified in their descriptions and understandings of the movement.

In her book entitled The Enlightenment, author Dorinda Outram takes a broader approach. She sees the movement from a global perspective. Outram examines the period from the vantage point of broader social changes that continually affect worldwide socioeconomic trends:

It is helpful ... to think about the Enlightenment as a series of interlocking, and sometimes warring problems and debates. These were problems and debates which affected how the Enlightenment worked not only in Europe, but also in the rest of the world.

The author proposes that the Enlightenment should be viewed from a wider social perspective. Historian Carl G. Gustavson follows a similar path in his text entitled A Preface to History. Gustavson argues that religious, technological, economical, and other societal forces coordinate over spans of time to become the causations of social changes:

No single cause ever adequately explains a historical episode. A “cause” is a convenient figure of speech for any one of a number of factors which helps to explain why a historical event happened. The analogy of the dominoes is misleading to the extent that we may think of the events as following mechanically upon the original act. The direction that the medley of causes will precipitate events can never be precisely gauged while the event is occurring.

Outram adopts this approach. Applying her theory in The Enlightenment to a movement like the Reformation, for example, one cannot conclude that the cause of that movement was the singular act by Martin Luther of nailing his ninety-five theses to a church door. Such a movement requires a combination of social forces. The same applies to the Enlightenment.

Outram opines:

Yet, in spite of all the ways in which Enlightenment interpretation has changed over the past decades, Enlightenment scholars have yet to come to grips with the issues of the relationship between the Enlightenment and the creation of the global world.

In Outram’s view, the Enlightenment spawned Romanticism, Liberalism, Classicism, and even twentieth-century Modernism, not as a result of something someone did or a single event or happening, but as the natural result of “the relationship between knowledge, critical reflection and power.” Governments adopted Enlightenment ideas and “prepared the way for the wave of revolutionary movements” that followed. The constant flux of Enlightenment ideas in the eighteenth century “helped or hindered rulers in their search for international success, and internal stability and prosperity.”

Dorinda Outram takes up the definition of the Enlightenment in the first chapter of her book, entitled The Enlightenment; however, the title of the chapter is actually, "What is Enlightenment," not "What is the Enlightenment."

Why "Enlightenment" and not "the Enlightenment?" Does it matter? For Outram, it does. According to the author, the Enlightenment has traditionally been seen by historians as an entity or a unitary phenomenon. Consequently, the traditional interpretation was replete with oversimplifications, such as the tendency to see French intellectual developments as typical and to emphasize certain themes, such as the victory of rationality over faith, through a selective sampling of the evidence. One might characterize this traditional approach as reductionist and limited.

For Outram, "the Enlightenment" (or more properly "Enlightenment," given her argument) was diverse, complex, and geographically widespread; in fact, it is even arguably still ongoing. In other words, it was not an entity or a unitary phenomenon.

After considering the myriad definitions and interpretations of the Enlightenment through a survey of the historiography, Outram settles on the notion that Enlightenment might productively be seen as "a capsule containing sets of debates which appear to be characteristic of the way in which ideas and opinions interacted with society and politics."

This approach affords her the flexibility to explore the topic in a more nuanced and historically accurate way.