There is a long and rich association of law with the arts of memory. In the Rhetorica ad Herennium (c. 80 BCE) (Caplan, Reference Caplan1954), one of the most influential guides to rhetoric ever composed, the very first example of a memory image offered is the following:

The function of this image is to help a lawyer to remember the case of a man who poisons (hence the cup) someone for their inheritance (hence the tablets, which are an image of the will). The final part of the image is the most striking: the fourth finger was thought, at the time, to be connected by a nerve to the heart; ram's testicles, in turn, offers a play on words, with ‘testiculi’ suggesting ‘testes’, and therefore two witnesses. The play on words serves not only as a reminder that two witnesses are required for a valid will. It also suggests something further: purses at the time were made of the scrotum of a ram and thus, in this context, ram's testicles may also point to the witnesses having been bribed by the poisoner, thereby having been complicit in the crime (p. 41). The reference to the fourth finger may suggest the whole scheme was premediated and carefully planned by the poisoner.

Frances Yates, the pioneer of the history of the arts of memory, characterised this image as a ‘classic memory image – consisting of human figures, active, dramatic, striking, with accessories to remind of the whole “thing” which is being recorded in memory’ (Yates, Reference Yates1966, p. 27). ‘It is as though,’ Yates continued, the lawyer ‘is forming a filing cabinet in memory of his cases. The image given is put as a label on the first place of the memory file on which the records about the man accused of poisoning are kept.’ If the lawyer wants to look something up about the case, ‘he turns to the composite image in which it is recorded, and behind that image on the following places he finds the rest of the case’ (Yates, Reference Yates1966, pp. 27–28). The picture, then, that Yates paints of the lawyer's knowledge is that of a filing cabinet – thereby ordered, or at least orderly – yet at the same time very much alive: it is full of striking images, behind which are stored further details, and which can be recalled when needed, such as in the course of oral argument.

Importantly, the above image is not only striking, and therefore memorable. It is also composite, as Yates noted, and thus relates certain elements together into a whole (the poison, the will, the witnesses). This is a kind of knowledge that consists less in the form of rules (although it may include rules, e.g. a valid will requires two witness) and more in the form of cases. And, perhaps most importantly of all, it is suggestive: the play on words (testiculi/testes) and the reference to a ram's scrotum, with its calling-to-mind of a purse, suggests that bribery of witnesses might be an important consideration in such cases. This knowledge may be ordered and composite, holding disparate elements together, but it is also a highly dynamic and playful mode of knowing. Indeed, it is a very inventive mode. Crucially, memory here is not a static repository, serving only the passive function of recall. Rather, memory is an inventive art: it is, as the Rhetorica ad Herennium itself characterises it, ‘the treasure-house of the ideas supplied by Invention … the guardian of all the parts of rhetoric’ (Book III.16, p. 206).

It is this inventive quality of the arts of memory that Seth Long investigates in his creative new book, Excavating the Memory Palace. The task he sets himself, however, is not merely to unearth a history that we tend to neglect. It is also to argue for its contemporary relevance, even in the most recent forms and varieties of digital media, which may otherwise seem to be far removed from the ancient art of rhetoric. This is a story and an argument that legal scholars would benefit from paying attention to. Not only might it help us to construct a more dynamic picture of legal knowing, and an account of reasoning with cases that helps us to see it as Janus-faced, creatively and prospectively refashioning past cases as new ones come along; it might also help us to design a digital legal ecology that enables the dexterity, suppleness and ingenuity that legal judgment needs.

The benefits, though, may well accrue the other way too: if law does have such a rich association with the arts of memory, scholars of rhetoric and literature may want to probe more the riches of law's imagistic catalogue (perhaps especially those relating to succession and inheritance, as in the above example). Given how striking the images of memory needed to be, one may well make a case for their central importance in literary history: might they not have influenced the developments of certain literary devices, styles and genres? And if, once again, the law turns out to be such a treasure trove of such memory images, this would allow the historian to weave together a new account of the entanglement of law and literature.

If we, in contemporary times, have lost sight of the connection between memory and invention – characterising the former as a rather passive repository of pale images of once-vivid experiences – we can perhaps take some unsatisfying solace in the fact that that link has often been neglected or cut in past ages. As Long points out, the link was strongest in the theory and practice of rhetoric in ancient Greece, as theorised by Aristotle and, later, the Roman rhetoricians Cicero and Quintilian. It was still very much prevalent in the medieval arts of memory (see Carruthers, Reference Carruthers1990; Reference Carruthers2000), flourishing in the scribal culture of the Christian monastery and expressed, for instance, in the writings of Alcuin of York, Hugh of Saint Victor and Thomas Bradwardine. But, over time, the link was weakened, first in England in the Early Modern period, and then in the Enlightenment in the rest of Europe. In England, according to a thesis by Yates and endorsed by Long, this was in large part due to the twin forces of Protestant iconoclasm and Ramism (a memory system devised by the sixteenth-century humanist, Peter Ramus, that did not employ the characteristic images of the arts of memory). In Europe, though still alive in the Early Modern Period, by the time of the long eighteenth century, memory was detached from invention and was ‘bowdlerised’, as Long puts it, ‘into a tool for rote memorisation, disconnected from any epistemological imaginative concerns’ (p. 7). Readers will find this history told succinctly, and indeed passionately, by Long in Chapters 1 to 4, with Chapter 1 devoted to the ancient memory arts, Chapter 2 to its medieval flourishing, Chapter 3 to its demotion, especially in England, and Chapter 4 to its less-than-triumphal resurgence in the eighteenth and nineteenth centuries. Chapters 5 and 6 turn their attention to the contemporary relevance of the memory arts for the digital age – a challenge I return to below.

First, though, we must confront the basic question: Why does the link between memory and invention matter so much? Why does Long think it is so important? What is it that is so crucial and distinctive about the ancient arts of memory, with its highly idiosyncratic, emotionally laden and sensory-rich imaginary? The answer is that this is how human beings – social, affective, sensory animals that we are – can know anything, but also know especially effectively, and thus in a way that can be creatively reused in a new set of circumstances. Such knowledge has to be not only stable and sticky, and thus likely to be recalled, but it also has to be such as to be capable of being adapted in the process of an engagement with others and the environment in the present. That process of engagement is active, playful and improvisatory, and thus the knowledge that supports it must be dynamic enough to allow that kind of engagement. Where that knowledge consists in the form of linguistically coded abstract information, it will not be retained well, and it will not enable the kind of inventiveness and ingenuity that that engagement requires.

Thus, the key idea underlying the memory arts is the combined stickiness and resourcefulness of networks of images. Put somewhat differently, the idea is that to know – in the dynamic way that we need to know – is to have an imagistically rich and affectively laden imaginary. To know is to see and feel, even if that seeing and feeling are simulated, and thus occur in the mind's eye and the mind's heart. This was, indeed, how the orator could know, and how he ought to know: it was via the network of images that the orator was able to ‘think on his feet’, and thus ‘find the right information at the right moment’ and ‘create new things out of old things’ (p. 17, quoting Whittemore, Reference Whittemore2015, p. 204). The orator's art, like that of other arts, was one of poiesis – a process of making – and this making was enabled by the dynamic resources of those fabricated and artificial composite images, which formed affectively resonant associations with each other.

Long provides us with many wonderful examples of the kinds of images recommended by the memory arts. The earliest, simplest, incipient kinds of memory images come from the Dossoi Logoi (c. 400 BCE), a treatise associated with the sophists and concerning arguments on both sides of an issue – a mode of argument all too familiar to law students and legal scholars. This treatise – and let us remember that it is almost 2,500 years old – recommends that, if the reader wants to remember the name ‘Chrysippos’, then ‘you must connect it with chrusos (gold) and hippos (horse)’ and ‘if you want to remember courage, think of Ares and Achilles’ (p. 26).

Later images become much more complex, of course, but already here we can see at work the idea that ‘memory is sensory, that it works via sensory rather than “logical” association’ (p. 26). Undoubtedly, the most iconic of these images is the one that constitutes a mnemonic for the very arts of memory – the famous origin story of the memory of Simonides:

The mnemonic technique discovered by Simonides is that of a spatial arrangement of images. This spatiality will go on to constitute a fundamental feature of the arts of memory, especially in the medieval period. Further, the imagery in this example is certainly striking: one easily simulates the mixture of relief and horror that must have been experienced by Simonides. Indeed, the violence in this image is typical of the images in the ars memoria – though they could also be exceptional in some other way, such as ‘beautiful, ugly, comic, colourful’ (p. 41). Once one arranged such striking images in some spatial way, then one could (e.g. the orator could) walk through the halls of one's memory, wandering, browsing and inventing. One could walk through it in this way both when one knew what one was looking for, but also, and perhaps more importantly, when one did not – then, the rich ‘associative assemblage’ (p. 45) one had built would help one to construct something new, by serendipitously stumbling upon something and relating it to something else.

This art of artificially created and spatially arranged networks of striking images received extensive attention in the medieval period, and it is quite possible that a significant motivation for that attention was the expansion of canon and civil law in this period, and the need for a technique to remember it (see p. 47). It would be fascinating to explore that link further – between canon and civil law, and the arts of memory – as scholars of this period tend to explore more the relation between the memory arts and religious scripture. Certainly, the kinds of memory practices developed in monasteries, and by medieval authors seeking to facilitate the inventive memory of scripture, are astounding. It is, for instance, in this period that the spatiality of memory takes on the form of ‘memory palaces’ – extraordinarily detailed and very carefully composed spaces, which allowed the construction of incredibly rich networks of images and thus of highly complex memory systems. Indeed, it is also in this period that one can witness the ‘flourishing of spatially ordered imagery in literature and art – a trend exemplified powerfully by The Divine Comedy's layered arrangement of heaven, hell, and purgatory’ (p. 71) – yet another example of how the arts of memory have influenced literary practices. We know, from the work of medieval legal historians, that spatial arrangements were also crucial to the organisation of legal knowledge in this period (see Stacey, Reference Stacey2018, Chapters 1, 2). It would be fascinating to explore these historically situated links between law, memory and the spatial imaginary further.

For theorists and historians of legal reasoning, especially in the common-law tradition, it is very significant that this art of memory comes to be replaced, in England in the Early Modern period, by a non-imagistic, non-affective alternative. The reception of this alternative is spurred on by the iconoclasm of Protestantism. The Ramist method is, as Long notes, ‘drained of all visual and inventive precepts’ (p. 99). This method focused on arranging the page in branching dichotomies, offering ‘an authoritative, easily taught, and easily memorised display’ (p. 99). But, though easily remembered, by giving up the imagistic and affective qualities of the memory palace, it also severed the link between memory and invention. The images of the ancient memory arts were embodied, sensory, three-dimensional. They were now replaced by two-dimensional and abstract branching dichotomies. Certainly, the Ramist method made information accessible, but it did not make it memorable in a way that facilitated invention. As Long puts it:

Protestantism could not stomach the graphic, sensual arts of memory. It replaced it with the flat world of Ramist dichotomies. But, in doing so, and in giving up this recognition of the vital spring, the source of creativity, that is an embodied, affective subjectivity, it also cut the link between memory and invention. Perhaps it was this change – cultural as much as theoretical – that pushed the history of theorising about legal reasoning to provide a picture of legal knowledge as a matter of knowing a system of rules that were to be more or less mechanically applied to present cases. The dynamism here, of the picture of knowledge in the arts of memory, is lost. In the rough ground of practice, however, it is likely to have been very different. Even if legal reasoning was increasingly theorised in England in a highly Protestant manner, its practice in the common-law tradition arguably continued to resemble something very much like a memory palace. The knowledge of a common lawyer, it might be said – and, as some, arguably recognised, such as Thomas Wilson in his The Art of Rhetoric (1553) – was and had to be imagistic, sensory, affective and inventive. It simply could not operate in any other way, even if the theorists did not want to see it that way, undoubtedly because this gave too much space to the allegedly illegitimate expression of subjectivity. How different the theory and history of common-law reasoning might be if we suffused it with the epistemology of the arts of memory.

As noted above, the aim of Long's book is not only to excavate a neglected history. It is also to argue for its relevance in contemporary times, dominated as this is by the technologies of social media. The final two chapters of Long's book canvas the possibility of a digital ars memoria. Arguing against what he identifies as a ‘digital iconoclasm’ of some contemporary media theorists, Long yearns instead for a digital ecology that would draw, once more, on the inventive qualities of visual, affective forms. Can we, he asks, recreate the kind of opportunities for serendipitous browsing that the old memory palaces enabled? Can we create visual information displays – new interfaces, which condense and spatially arrange information – that invite rhetorical activity? His answer is that yes, we can, and that, moreover, we should.

Legal scholars may want to examine carefully his examples – which include uses of visualisation tools such as Gephi, and more well-known text networks (for an interesting recent discussion of the generative power of such networks, see Ahnert et al., Reference Ahnert2020). It may be that some of these can be harnessed to design a new way of organising and expressing legal knowledge – prompting rather than shutting down invention strategies. A text network, for example, relates words to each other; it connects words and phrases that would otherwise ‘never or rarely cross paths’ (p. 171). Some network visualisations may prompt us to imagine – to generate possibilities – and this could aid the process of inquiry in legal reasoning. There are other examples here too – such as various digital map-making practices (Long discusses Google Earth and Google Maps: see pp. 171–180) – which enable a view to balance multiple perspectives simultaneously and offer, again, highly generative epistemic resources.

As Long argues, there is an important proviso to these kinds of devices being epistemically generative: we must not forget their artificiality. As long as we treat these kinds of visualisation as provisional – as artificial devices, akin to artificial memory practices – we will not fall into the trap of idolising them. Protestantism here becomes a source of an important insight: of the dangers of images turned idols. But Protestantism also took things too far: it threw the baby out with the bathwater. We need not discard images (or their digital versions), but only so long as we treat them as distortions – as artificial constructs that are the starting points for, rather than outcomes of, inquiry. Are we capable of remembering the artificiality of these devices – their constructedness? Long is optimistic, while other theorists are less so. The key must be to combine the teaching of critical visual and digital literacy with visual and digital forms that do not hide away their own artifice. In any event, Long is surely right to argue that there are opportunities here to be mined, and thus prospects for a digital epistemic practice that gives us new tools for making knowledge. Perhaps, indeed, there is a case to be made for a new digital legal ecology – one that links the digitisation of legal knowledge productively with our epistemic practices as embodied, affective and imaginative animals.

Long's book is a timely reminder that there are both great promises and great dangers lurking in new technologies, but that these cannot be appreciated without a historical sensibility. No matter how new-fangled technologies may seem, they will raise similar questions as in the past about what it is for us, as humans, to know. In this book, Long does us a great service by excavating the long and rich history of the arts of memory. We may want to add to that history, recasting other canons of rhetorical practice, such as style and delivery, for critical reflection on technological developments. In the meantime, we have Long to thank for the idea that the history of rhetoric might turn out to be our best guide to the digital age.