How can economics become genuinely quantitative? This is the question that French sociologist Gabriel Tarde tackled at the end of his career, and in this pamphlet, Bruno Latour and Vincent Antonin Lépinay offer a lively introduction to the work of the forgotten genius of nineteenth-century social thought. Tarde’s solution was in total contradiction to the dominant views of his time: to quantify the connections between people and goods, you need to grasp “passionate interests.” In Tarde’s view, capitalism is not a system of cold calculations—rather it is a constant amplification in the intensity and reach of passions. In a stunning anticipation of contemporary economic anthropology, Tarde’s work defines an alternative path beyond the two illusions responsible for so much modern misery: the adepts of the Invisible Hand and the devotees of the Visible Hand will learn how to escape the sterility of their fight and recognize the originality of a thinker for whom everything is intersubjective, hence quantifiable.

At a time when the regulation of financial markets is the subject of heated debate, Latour and Lépinay provide a valuable historical perspective on the fundamental nature of capitalism.

In this thought-provoking work, Tony D. Sampson presents a contagion theory fit for the age of networks. Unlike memes and microbial contagions, Virality does not restrict itself to biological analogies and medical metaphors. It instead points toward a theory of contagious assemblages, events, and affects. For Sampson, contagion is not necessarily a positive or negative force of encounter; it is how society comes together and relates.

Sampson argues that a biological knowledge of contagion has been universally distributed by way of the rhetoric of fear used in the antivirus industry and other popular discourses surrounding network culture. This awareness is also detectable in concerns over too much connectivity, such as problems of global financial crisis and terrorism. Sampson’s “virality” is as established as that of the biological meme and microbe but is not understood through representational thinking expressed in metaphors and analogies. Rather, Sampson interprets contagion theory through the social relationalities first established in Gabriel Tarde’s microsociology and subsequently recognized in Gilles Deleuze’s ontological worldview.

According to Sampson, the reliance on representational thinking to explain the social behavior of networking—including that engaged in by nonhumans such as computers—allows language to overcategorize and limit analysis by imposing identities, oppositions, and resemblances on contagious phenomena. It is the power of these categories that impinges on social and cultural domains. Assemblage theory, on the other hand, is all about relationality and encounter, helping us to understand the viral as a positively sociological event, building from the molecular outward, long before it becomes biological.