`How did the system work? By magic of course, by being based on the central power station of the … images of the stars, closer to reality than the images of things of the sublunar world, transmitter of the astral forces, the `shadows’ intermediary between the ideal world above the stars and the objects and events in the lower world.’ (The Art of Memory, p. 223)
This interpretation, based on a misplacing of the images of the planets, was first revised by Rita Sturlese in her critical edition of the De Umbris of 1991 (pp. LXVIII ff.) and later by Francesco Torchia (‘La chiave delle ombre’, Intersezioni, 1, 1997, pp. 131-151). Both scholars strip Bruno’s construction of its magical character. According to Sturlese the wheel is in fact an adult toy conceived to learn foreign words. Here each ray corresponds to a set of syllables combining one consonant with one vowel. Thus reconstructing a word with its phonetic constituents amounts to combining the various elements of each section. The addition of the images described in the last ring before the hub creates in the end a mnemonic background by means of which new words can be remembered. For instance to remember the word Numeratore you should pick the first syllable in the outer ring, NU, which corresponds to `Apis’; the second syllable in the second ring, ME: `in tapeta ’; the third syllable, RA, in the third ring: `deploratus’; the fourth syllable, TO, from the 4th ring: `compedes’; and finally RE in the 5th ring. This last ring provides a background against which to set the image thus created: `…mulier super hydram tres cervices e quarum singulis septem exiliunt capita habentem, vacuas antrorsum tendens manus’ (De Umbris, p. 151).
Thus you can remember the word numeratore through the following image composed by the combinatory wheel:`the god Apis weaving a rug and wearing rags with wood blocks on his feet, with, in the background, a woman stretching out her hands and riding an hydra with many heads.’
Torchia's objections to this system are too long to be listed here. His main point, following the traditional criticism of classical mnemonics, is that it requires far more cognitive effort to memorise the images than the words themselves. His observation that the figures placed on the outer ring of the wheel represent all the inventors of all the arts suggests that Bruno's object could serve as a means of discoursing on and memorising any subject, very much in the spirit of Giulio Camillo del Minio's memory theater (ibid. p. 146). This interpretation places a central importance on the images of the planets. The practitioner of the art will himself select the agent and the actions for memorising an argument and associate his selection with the astral image corresponding to the figure of inventors selected on the first outer ring (see Torchia p. 148). In this interpretation the image composed is associated with a narrative, now embedded in the astral figure.
Such object can in fact be put to many uses. To the sources used by Bruno and listed by Mino Gabriele (Giordano Bruno: Corpus Iconographicum, pp. 36-40) could be added Leon Battista Alberti's ingenious system, expounded in his book on ciphers, by which wheels very similar in appearance to those illustrated in the De Umbris Idearum serve the purpose of coding and decoding messages - a method that can be applied to Bruno's mnemonic system. Thus while Frances Yates's earlier reconstruction is not completely accurate, and her assumption that the wheel worked by magic as an inner talisman is no longer tenable, it still offers a useful visualisation of the complex and powerful system Bruno had in mind.
Scholarship has greeted Yates's views on Bruno and Hermeticism with considerable scepticism while less specialised literature continues to repeat her findings thanks undoubtedly to the greater diffusion of English language literature as much as to the outstanding clarity of her style. She nevertheless remains one of the first English speaking scholars to have highlighted the importance of early modern mnemonics. Writing in the early 60s, and criticised for detaching the past from Modernity, she could not anticipate that the art of memory would experience a true renaissance. Today thanks to recent technology a single individual can carry several thousands of texts, sounds and images in a container smaller than a pack of cigarettes and access them through a screen. Thus Frances Yates's studies on the survival of the Ancient art of visually organising, combining and retrieving knowledge may now be apprehended as early modern solutions to eminently contemporary problems.