Dominant Extraverted Intuition (Ne): Leonardo da Vinci was a man of many ideas and of equally many talents. He was constantly devising new machines, and experimented so much with chemicals in his paintings that many of them have deteriorated more rapidly than much older paintings. Da Vinci’s imagination so outstripped current technology that he was unable to build many of the machines he designed (though people today can look at his diagrams and construct accurately, the things that he designed without having ever set foot in our era). Leonardo connected all of his major paintings to theoretical concepts, including the mathematical theories of Vetruvius and the revival of Platonic ideals that was occurring during his time period.
Auxiliary Introverted Thinking (Ti): Da Vinci was was well known for getting so distracted by his ideas that he failed to finish the projects he was working (including those projects he had been commissioned to complete). Da Vinci enjoyed erasing the lines that separated the arts and the sciences. His work is innovative, but also mathematical, scientific. In effort to achieve anatomical realism, he sought out cadavers, which he frequently dissected in order to understand them. Da Vinci was constantly challenging himself, both in the arts, and in the sciences.
Tertiary Extraverted Feeling (Fe): One thing that still fixates art historians on da Vinci’s work was his attention to psychological realism within his portraiture. He gives many of his characters and sitters expressions of ambiguity, but also of realistic emotional states. Leonardo da Vinci maintained an outlook of optimism throughout his life, but did not ponder much on the state of his feelings in his writings.
Inferior Introverted Sensing (Si): Da Vinci built upon the ideas of painters who lived before him. He practiced sketching the great masters and then improved upon their work with his own discoveries. Da Vinci was the type of painter who would get attached to paintings and not want to relinquish them (he did not give the Mona Lisa to the patron who commissioned it, but instead, kept it with him for the remainder of his life).