Leonardo describes here (with admirable exactitude), the myological apparatus of facial expressions. The verbal explications and letter-marks on the drawings locate the «muscle of rage» (h), the «muscle of pain» (p), and again, the whole system of «rage» (g-n-m). Our page, however, insinuates a doubt as to whether the precise findings of the anatomical dissection can, after having explained the physiognomy of emotions, also pin-point their ultimate origin: «Represent all the causes of motion that do the skin, flesh and muscles of a face, and see if its muscles receive their motion from the nerves which come from the brain or not [my emphasis]» (Figura tutte le cause del moto che ha la pelle, carne e muscoli d’un viso, e se li muscoli sua hanno il moto dali nervi che vengan dal cervello o no).

Leonardo may be questioning here Aristotle’s conviction that the heart is the site of all sentiments and the nucleus of bodily movement (‹change› in the Aristotelian terminology), both voluntary and involuntary (De Anima A 402b, et passim). He may therefore be alluding to the Galenic position, namely, that even if the heart is the seat of emotions it is the brain that moves the body in response to them. But even so, locating this seat and explaining empirically how the observable corporal effect springs from the invisible origin are two different things. So he takes no side and halts at this treacherous threshold.

The small drawing in the right corner, of the leonine warrior stamped with the marks of vita activa, may be the only answer he deigned to give to this question at this moment, and in this context. This is not a case of absentmindedness, for in fact this warrior joins the ways in which Leonardo’s constantly bypasses the problem of soul-body connection wherever it surfaces, inevitably of course, in his mature anatomical studies.

In 1509–10 Leonardo’s intellectual temperament and disposition, as Domenico Laurenza has shown, drove him away from his early approach to the body as a composite, quantitative construction, towards its vision as complex processes of life. [37] The skull-studies of 1489 have located the soul in the purported intersection of sense-channels, along which the similitudini of the objects travel. This was a physical locus in the brain, a privileged, ideologically charged point. But the mature anatomies convey a different stance regarding the soul and the mind. They shift towards non-speculative observation, and tend in a greater degree to infer physiological function from anatomical and morphological form. Accordingly, the notion of the soul now emerges more as a hiatus and a liminal idea.