Agent Quotes - page 24

The birth and inauguration of the generic telegraph has not only opened a new field for the labors, and given direction to the ingenuity of the mechanician, suggesting numerous varieties of form and distribution of parts, but it has also give a fresh impulse to the researches of the philosopher into the mysteries of the most efficient agent, electricity. It has been the servant of the astronomer; it has assisted in the determination of longitudes; ... it has promoted the science of meteorology, and been tributary in many ways to the advancement of our knowledge of terrestrial phenomena. ... (Samuel F. B. Morse)
Shadow is not the absence of light, merely the obstruction of the luminous rays by an opaque body. Shadow is of the nature of darkness. Light is of the nature of a luminous body; one conceals and the other reveals. They are always associated and inseparable from all objects. But shadow is a more powerful agent than light, for it can impede and entirely deprive bodies of their light, while light can never entirely expel shadow from a body, that is from an opaque body. View quote
Leonardo da Vinci
It is inconceivable that inanimate brute matter should, without the mediation of something else which is not material, operate upon and affect other matter without mutual contact, as it must be, if gravitation in the sense of Epicurus, be essential and inherent in it. And this is one reason why I desired you would not ascribe innate gravity to me. That gravity should be innate, inherent, and essential to matter, so that one body may act upon another at a distance through a vacuum, without the mediation of anything else, by and through which their action and force may be conveyed from one to another, is to me so great an absurdity that I believe no man who has in philosophical matters a competent faculty of thinking can ever fall into it. Gravity must be caused by an agent acting constantly according to certain laws; but whether this agent be material or immaterial, I have left open to the consideration of my readers. View quote
Isaac Newton