A recently discovered drawing of a horse by Leonardo da Vinci gives us the opportunity to highlight the ubiquitous use of the golden ratio by the master, confirming the Greek inspiration of who was nicknamed the “new Phidias”. The horse drawn by Leonardo can be seen as an “ideal horse”, with perfect measurements for the body as well as the head, according to the “divine proportion”, i.e. the golden ratio. This also allows us to point out a very good approximation and simple geometric construction of the golden ratio.
From the end of the 19th century onwards, a renewed approach to the spectator’s perceptive act in the theoretical discourse on art was asserted, concomitantly with the psychological and philosophical discourse. The spectator’s act of perception would explain certain pictorial illusions. Beyond that, the perceptive act could play a new role in the apprehension of a colour or a quality of texture, linking it, by association or equivalence, to other sensations, tactile, olfactory, sonorous, just as immediately perceived by going beyond the naturalistic principles of imitation. In this paper, I will first highlight the evolution of one of the theories of art focusing on the notion of suggestion, then to show how different non-figurative propositions after the Second World War are in line with the continuity of this conception through a creative research on how to make perceptible on a flat surface an impression of depth, expanse, or swirls; a matter or a form perceived as sharp or rough, not trying to depict either the object or a sensation but to create an "equivalence that determines a sensation" (P. Tal Coat). In parallel with a revival of psychology, considering that our perception establishes relationships in the visual field, that we grasp structures significant to all the senses, many artists started a creative research on how to make visible sensations anchored in their experience of the sensitive world, which for them often give rise to others, emotional or spiritual, inducing a feeling "beyond words and intellectual frameworks" (D. Vallier). The singular nature of this aesthetic, which maintains an unexpected link with reality, provokes a debate on its attachment to abstract art.
The relationship between the mineral and the living has always been a subject of debate, but nowadays it is of growing interest, probably due to scientific advances that have blurred the classical distinction between living and non-living. The first part of this article explores various passages from mineral to living: in ancient stories (Genesis and Greco-Roman mythology) and contemporary role-playing games on the one hand, and in the emergence of life on the other, as understood by science over the centuries. The second part focuses on the reverse passages, from the living to the mineral: several possible mineralizations of organisms, in vivo (biomineralizations) and post mortem (fossilizations, petrifications), with their artistic and literary revivals, are thus addressed. The third part evokes the proximities between the mineral and the living: natural proximities (in particular those involving epiliths such as lichens) or due to humans (from prehistoric cave paintings to Arte povera). We will finally see how certain writers and artists reach a true intimacy with the mineral world in which they project themselves and find themselves.