"My powers are ordinary. Only my application brings me success."

"The causes of gravity are not yet discovered. It is by experiments and observations that we are to know them."

"Every body continues in its state of rest, or of uniform motion in a right line, unless it is compelled to change that state by forces impressed upon it."

"Gravity explains the motions of the planets, but it cannot explain who sets the planets in motion."

"For the best and safest way of philosophizing seems to be, first to inquire diligently into the properties of things, and of establishing them by experiment, and then to proceed more slowly to hypothe…"