In the centuries that followed, accounting was joined by statistics, economics, surveys and a range of other numerical methods. But even as these methods expanded, they tended to be the preserve of small, tight-knit institutions, academic societies and professional associations who could uphold standards. National statistical associations, for example, soon provided the know-how for official statistics offices, affiliated with and funded by governments.

In the 20th century, an industry for facts emerged. Market-research companies began to conduct surveys in the 1920s and extended into opinion polling in the 1930s. Think tanks like the American Enterprise Institute were established during and after World War II to apply statistics and economics to the design of new government policies, typically in the service of one political agenda or another. The idea of “evidence-based policy,” popular among liberal politicians in the late 1990s and early 2000s, saw economics being heavily leaned on to justify government programs, in an allegedly post-ideological age.

Of course the term “fact” isn’t reserved exclusively for numbers. But it does imply a type of knowledge that can be reliably parceled out in public, without constant need for verification or interpretation.

Yet there is one much more radical contributor to our post-truth politics that could ultimately be as transformative of our society as accounting proved to be 500 years ago.

We are in the middle of a transition from a society of facts to a society of data. During this interim, confusion abounds surrounding the exact status of knowledge and numbers in public life, exacerbating the sense that truth itself is being abandoned.

The place to start in understanding this transition is with the spread of “smart” technologies into everyday life, sometimes called the “internet of things.” Thanks to the presence of smartphones and smartcards in our pockets, the dramatic uptake of social media, the rise of e-commerce as a means of purchasing goods and services, and the spread of sensory devices across public spaces, we leave a vast quantity of data in our wake as we go about our daily activities.

Like statistics or other traditional facts, this data is quantitative in nature. What’s new is both its unprecedented volume (the “big” in big data) and also the fact that it is being constantly collected by default, rather than by deliberate expert design. Numbers are being generated much faster than we have any specific use for. But they can nevertheless be mined to get a sense of how people are behaving and what they are thinking.