To begin our journey through the landscape of images with Leonardo’s Mona Lisa may seem obvious and even banal. But even such a familiar work can be scrutinised
through fresh eyes if we set aside our stock categories of art and science. For Leonardo the invention of a compelling image was not based on literal imitation of nature or unlicensed imagination but on the remaking
of natural effects through the understanding of natural laws derived from ‘experience’. The inventor’s imaginative faculty or fantasia worked in concert with the intellect to recreate an infinity
of plausible images.
Before looking at the way in which Leonardo’s portrait of a lady embodies his philosophy of nature, we should try to discover her identity. If we strip
away the myths of ages, it is now reasonably clear that she was indeed ‘Madonna Lisa’, the wife of a prominent Florentine citizen, Francesco del Giocondo - hence her nickname, ‘La Gioconda’,
which can be translated as ‘the smiling one’. It is likely that Leonardo commenced her portrait in about 1503 and continued to work on it over a number of years, perhaps more than a dozen. In that
time it became less of a portrait and more of a universal statement.
In this painting as in all others by Leonardo, every painted effect was, in theory, based on a natural law. For our present purposes I will highlight just four which
are inherent in the Mona Lisa, restating in more compact form what Leonardo wrote about the phenomena of light on surfaces, the formation of spiral configurations, and the huge changes in the bones, flesh and blood
in the ‘body of the earth’.
Law 1 ‘The intensity of light on a plane is proportional to the angle of impact of the light on that plane.’
Thus, on a human head, light from a point source will make its strongest impact when it strikes a surface perpendicularly. When it strikes a glancing blow, the
intensity of light at that point will be proportionately weaker. The relative intensities of light on any solid body must be characterised according to this rule. Convex and concave surfaces will exhibit smooth
transitions from proportionately lighter to proportionately darker.
In the eighteenth century Johann Heinrich Lambert established that the brightness was proportional to the cosine of the angle between the line of sight and that
normal to the plane - the law now observed in computer rendering.
Law 2 ‘A helix arises from the combination of two components: a straight axis corresponding to
a linear motion or a weight acting in a vertical direction; and a circular motion or shaping force in a plane perpendicular to that axis.’
Thus, a current of air or water will exhibit a desire to move forward, just as a weight desires to fall, but will be deflected by successive impacts to induce a
revolving impetus, just as a substance that has an inherent desire to curl, such as hair, will be disposed to turn around the axis of its weight. Phenomena that involve direct and revolving impulses include vortices
in water currents, ringlets of hair, gathered or compressed drapery, the growth of leaves in plants, shells of marine creatures, spiral staircases and conical gears for clocks.
Law 3 ‘The relative positions of the sphere of water and the “body of the earth”
are constantly in flux, such that different zones of solid earth are extruded from the sphere of water and become subject to erosion, while the inner caverns of the earth are also subject to periodic collapse.’
Thus mountains are eroded at their bases, eventually collapsing and damning rivers to form lakes at different levels, the higher of which will in time burst forth
leaving stranded water creatures - as is witnessed by the deposits of ancient shells in high places.
Law 4 ‘The body of the human being as a microcosm or “lesser world” is vivified by the pulsing of the blood in its vessels just as the “body of the earth” is given life by the waters that ebb and flow across and within it’. The woman and the landscape stand in profound harmony to each other and to the laws that govern the physical world.