In an illuminating exchange, Charles Hirschkind and Alireza Doostdar debate the compulsory quality of modern scientific reasoning. Doostdar, in The Iranian Metaphysicals, emphasizes the agency of Iran’s “metaphysical” practitioners. Modern science, on this view, has opened the doors of knowledge production to social classes outside the old scholarly elite. As new “possibilities for reasoning become available,” Doostdar shows, a motley cast of healers, Spiritualists, and occultists appropriate them for their own, frequently heterodox, ends. Hirschkind, however, worries that this analysis is too optimistic: it presumes that the modern subject apprehends science through a free market of ideas. In fact, certain manners of thought are so basic to our everyday functioning that to say we choose them is to overstate our self-awareness, let alone our free will. “Scientific rationalism is not simply an epistemological possibility,” Hirschkind writes, “but an ontological condition.”

Doostdar offers a helpful rejoinder to this critique. As he points out, it is simply not the case that modern scientific reasoning has become hegemonic in every context. In fact, most of the movements Doostdar describes were ephemeral when compared with the enduring power of the howzeh and its “scholarly theology.” Yet, Doostdar concedes, even the latter has acquired new meaning to the extent its practitioners must at least articulate their stance on empiricist knowledge. If modern scientific reason is not quite compulsory, it is certainly unavoidable.

The methodological problem here is to account for the extent to which modes of reasoning are both chosen and prior to choice. Hirschkind offers this useful formulation of the challenge: “How do we hold together . . . an appreciation of the diverse sources of authority by which [people] make sense of their lives and the conscripting powers put into place by the juggernaut of Western modernity?”

I approach this question by way of a tangent. In an arresting description of the meetings of the Society of Experimental Spirit Science in Tehran in the mid-1920s, Doostdar writes:

The staple event each week was a séance. If a suitable medium—often a young, frail woman—was available, she would be hypnotized . . . in order to enter a trance state and communicate with the spirits of deceased individuals awaiting reincarnation. Once contact was established, the medium would write down the spirits’ messages or speak them out loud. In the absence of mediums, members would sit around a wooden table and communicate with the spirit world telegraphically using a wooden cigar box that glided on a sheet inscribed with the letters of the Persian and French alphabets.

The appearance of something like a Ouija board in interwar Tehran is not particularly surprising. Talking boards and tables were a staple of Spiritualist practice, from its heyday in the late nineteenth century to the twentieth-century fascination with the “paranormal.” The instruments of Tehran’s Society of Experimental Spirit Science would have been comfortable in the salons of imperial St. Petersburg, and they would be just as familiar to readers of an Arthur C. Clarke novel in the 1950s.

It is this broadly shared material culture that strikes me. What Doostdar terms “the rationalization of the unseen” was a materially mediated practice, a means of producing knowledge through specific, agreed-upon arrangements of people and things. Perhaps we can draw here on the work of Hans-Jörg Rheinberger, who has called for greater attention to the dynamic relationship between instruments and objects in the history of the experimental life sciences. According to Rheinberger, “the process by which a research instrument gradually takes shape meshes with that by which an epistemic object is gradually built up: the two go hand in glove.” Thus, for example, magnifying lenses did not simply reveal the microscopic world for observers to interpret. Rather, if we want to understand the relationship between light microscopy and the emergence of the modern life sciences, we should attend to the craft of the preparation, the elaborate and evolving protocols by which experimentalists sliced and (later) dyed their objects of knowledge. Rheinberger argues that experimental knowledge emerges on the landscape of such “intersections” between instrument and object. In practice, in other words, empiricism is less a set of a priori principles than a form of material culture: a socially agreed upon way of manipulating and relating specific objects as well as understanding what they mean.

I suggest that something of this perspective can be brought to bear on the practitioners whom Doostdar describes in his book. Rather than producing knowledge about cells or genes, of course, they sought to understand the soul. They did so, however, with specific things: their instruments, such as the talking board. Indeed, the human medium here should also be understood as an instrument, much as model organisms have provided many of the modern life science’s most powerful instruments. It is worth noting that Spiritualists preferred female mediums for their supposed “passivity,” just as the ideal instrument is supposedly innocent of any effect on the phenomenon it makes visible. Other instruments (including therapeutic technologies) appear throughout Doostdar’s ethnography: talismans, prayer inscriptions, and pieces of string folded into copies of the Quran.

It would be interesting to know more about these things. How did they become available to their users, and by what criteria were they selected? What were their histories of production and use? What interpretive disagreements did they generate? What were they understood to allow, and what limitations did they impose, within their “experimental system”? Such instruments do not fall neatly into the dichotomous interpretation that Hirschkind and Doostdar debate, in which scientific reasoning is either a “possibility,” to be freely chosen, or a “condition,” within which choice is constrained. Instruments are, to be sure, unstable ingredients of a creative process. They do not determine any outcomes by themselves. But they are not empty vessels. Tehran’s Spiritualists in the 1920s could construct their talking board with Persian and French letters, but they could not talk to the dead with Tiddlywinks. Instruments carry certain material conditions, and—as importantly—they are burdened by the weight of experience, supposition, and interpretation that they have accumulated within a community of users. These burdens do, of course, change over time. But it may be in this space of friction—among practitioners, instruments, and objects of knowledge—where agency and power are negotiated.