There are four Powers: memory and intellect, desire and covetousness. The two first are mental and the others sensual. The three senses: sight, hearing and smell cannot well be prevented; touch and taste not at all. – Leonardo da Vinci
I have found that, in the composition of the human body as compared with the bodies of animals, the organs of sense are duller and coarser. Thus, it is composed of less ingenious instruments, and of spaces less capacious for receiving the faculties of sense. – Leonardo da Vinci
The beginnings and ends of shadow lie between the light and darkness and may be infinitely diminished and infinitely increased. Shadow is the means by which bodies display their form. The forms of bodies could not be understood in detail but for shadow. – Leonardo da Vinci
I have always felt it is my destiny to build a machine that would allow man to fly. – Leonardo da Vinci
I have been impressed with the urgency of doing. Knowing is not enough; we must apply. Being willing is not enough; we must do. – Leonardo da Vinci
In order to arrive at knowledge of the motions of birds in the air, it is first necessary to acquire knowledge of the winds, which we will prove by the motions of water in itself, and this knowledge will be a step enabling us to arrive at the knowledge of beings that fly between the air and the wind. – Leonardo da Vinci
Necessity is the mistress and guide of nature. Necessity is the theme and inventress of nature, her curb and her eternal law. – Leonardo da Vinci
Many are they who have a taste and love for drawing, but no talent; and this will be discernible in boys who are not diligent and never finish their drawings with shading. – Leonardo da Vinci
There are three classes of people: those who see, those who see when they are shown, those who do not see. – Leonardo da Vinci
Although nature commences with reason and ends in experience it is necessary for us to do the opposite, that is to commence with experience and from this to proceed to investigate the reason. – Leonardo da Vinci
Painting is concerned with all the 10 attributes of sight; which are: Darkness, Light, Solidity and Colour, Form and Position, Distance and Propinquity, Motion and Rest. – Leonardo da Vinci
The poet ranks far below the painter in the representation of visible things, and far below the musician in that of invisible things. – Leonardo da Vinci
Nature is the source of all true knowledge. She has her own logic, her own laws, she has no effect without cause nor invention without necessity. – Leonardo da Vinci
Iron rusts from disuse; water loses its purity from stagnation… even so does inaction sap the vigor of the mind. – Leonardo da Vinci