IPL and its constituent elements weren’t just epistemologically significant for the study of minds-as-information-processors. They mattered for logic as well. Linked lists lived in JOHNNIAC’s memory, yes. But theyalso lived on paper where they were invented, devised, explained, and explored by the human practitioners who imagined them into being. Indeed, it was in the archives, on paper, where I discovered them as well - it being impossible for us to ever see a linked list in computer memory at all. The architects of the Logic Theory Machine surrounded themselves with paper in new ways, they used paper to represent new things to themselves in new ways.
By asking after the character of linked lists, by looking for their origins, and by following them to their different sites and instantiations, we saw how complicated it was to put even a tiny part of the world into a computer. We uncover some of the difficult involved in rethinking the world through a materiality largely inaccessible to human experience and sensibility. And we saw new ways that the work of theorem-proving was done in the early years of this digital age.
At the same time as the program was being worked out and implemented, new tools for people were also being developed. Computers never replace human labor, they always transform and displace it. In one sense, the linked list replaced paper. Logical propositions were no longer inscribed sequentially on the page to be taken in and compared synthetically by human vision. They were inscribed in JOHNNIAC memory, dispersed, scattered, held together by a chain of address pointers. There they could not be seen by a human practitioner and there they could not be taken in as a whole at a glance, but had to be traversed according to list processing operations into which the logical rules of inference and demonstration were transformed.
constructed by way ofdiagramming. The figures from the earlier sections of this chap- ter are pictures of paper - the ways of drawing and writing that accompanied the development and implementation of linked list structures. Newell, Simon, and Shaw did not get rid of paper. They put paper to work in a new way.144 They developed
linked lists diagrammatically on the page.
I claim that linked list diagrams are very interesting relative to the question of representation. What do linked list diagrams represent exactly? They represent two things at the same time: they represent both logical propositions and JOHNNIAC memory. They represent the thing to be digitized and the digital media together. This hybrid or dual representational scheme points to part of what is involved in carving out a place for computers in knowledge-production. Practitioners had to find ways of thinking about what the computer is, of representing it, and of working with it at the same time as they re-imagined their part of the world, their objects of interest, as digital things. Linked list diagrams are a trace of how mathematical objects were recon- ceptualized through the lens of computing at the same time as computing machines were being re-tooled and outfitted for mathematics. Linked lists were not merely rep- resentations of logical propositions, they were representations that introduced discrete, digital, computational, algorithmic, and processual properties to them.145 Linked lists
hybridized properties of logical propositions and Johnniac memory.146
144This is in fact a common phenomenon in the history of computing. Recent media scholars have
shown how the “paperless office” is in fact a myth and that paperless offices are populated with all kinds of paper and paperwork. See for example, Abigail J. Sellen and Richard H.R. Harper,The Myth of the Paperless Office (The MIT Press, 2003); Kirschenbaum, Matthew G. "Editing the Interface: Textual Studies and First Generation Electronic Objects" in Text: An Interdisciplinary Annual of Textual Studies 14 (2002): 15-51.; Mark Priestly and Thomas Haigh are also currently working on the forms of flow diagramming that accompanied early uses of the ENIAC computer - often associated with the “programming by plugging” practices that predated punch tape and punch card programming.
145For a more philosophical exploration of the “dynamism” of computational objects, see Brian
Cantwell Smith,On the Origin of Objects (Cambridge, MA: The MIT Press, 1996).
146A related claim is made by David Nofre, Mark Priestly, and Gerard Alberts in “When Technology
Became Language: The Origins of the Linguistic Conception of Computer Programming, 1950 - 1960” in Technology and Culture, Vol. 55, No. 1 (January 2014): 40 - 75. They explore how early
Some fascinating scholarship has been produced by anthropologists and historians who are interested in the role that written symbols and notational systems play in the history of human cognition. One early study was anthropologist Jack Goody’s work in The Domestication of the Savage Mind.147 He argued that the minds of tra-
ditional peoples and the minds of Western Europeans were not separated by some essential difference as had been proposed by his more colonially minded predecessors and colleagues. Instead, he believed that the cognitive abilities of all peoples were a product of their “technologies of literacy.” He argued that ways of writing, recording, manipulating, and circulating information enabled and constrained memory, reason, and cognition. The “list” is one such literary technology that he identifies as important in the history of commerce, logical reasoning, and experiences of temporality. In a section called “What’s in a list?” he writes:
The list relies on discontinuity rather than continuity; it depends on phys- ical placement, on location; it can be read in different directions, both sideways and downwards, up and down, as well as left and right; it has a clear-cut beginning and a precise end, that is, a boundary, an edge, like a piece of cloth.148
In a different vein, Hans-Jörg Rheinberger has emphasized the epistemological signif- icance of note-taking and data recording practices among experimental scientists in determining the outcome and understanding of what was shown in an experiment.149
Some scholars in philosophy have suggested that, in fact, if certain symbol systems are so inextricable a part of cognition, perhaps they should not be understood as aids to
programming languages had a kind of dual representational function in that they had to represent to the computer and they had to represent to the programmer. Early languages combined the needs of programmers and machines.
147Jack Goody,The Domestication of the Savage Mind (Cambridge University Press, 1977). 148Goody,The Domestication of the Savage Mind, p. 81.
cognition but rather aspart of cognition itself.150 Lists and other literary technologies
like tables, graphs, and diagrams have received interest more recently as well among historians of science, technology, and economics. These accounts are often motivated by an interest in the kind of thinking that particular inscriptions enable or exclude. Data structures like linked lists can be thought of as new literary technologies that enable new ways of “thinking with computing.”
The drawing and diagramming techniques deployed by Newell, Simon, and Shaw to represent logical expressions don’t just point to new materiality for logical expressions - they point to new thinking about logical expressions. And in particular, Newell, Simon, and Shaw were not thinking about logical expressions in order to prove theorems directly, they were thinking about logical expressions in order to program a computer to prove theorems. The interventions of the technology in the cognitive goals and resources of its users are reflected in the new tools they design for working with old objects. Processes of automation seldom, if ever, replace human thought. Instead, automation attempts rather displace and transform human thinking at the same time as they enable the construction of new objects of thought - these develop always in tandem. And, as I will reiterate throughout in the dissertation I am less interested in the question of whether machines are thinking than I am in the changes in human thinking that surrounded the use of computing machinery.