In the first[108] of these letters Sir Isaac mentions that when he wrote his treatise about our system, viz. the Third Book of the Principia, “he had an eye upon such principles as might work, with considering men, for the belief of a Deity, and he expresses his happiness that it has been found useful for that purpose. In answering the first query of Dr. Bentley, the exact import of which we do not know, he states, that, if matter were evenly diffused through a finite space, and endowed with innate gravity, it would fall down into the middle of the space, and form one great spherical mass; but if it were diffused through an infinite space, some of it would collect into one mass, and some into another, so as to form an infinite number of great masses. In this manner the sun and stars might be formed if the matter were of a lucid nature. But he thinks it inexplicable by natural causes, and to be ascribed to the counsel and contrivance of a voluntary Agent, that the matter should divide itself into two sorts, part of it composing a shining body like the sun, and part an opaque body like the planets. Had a natural and blind cause, without contrivance and design, placed the earth in the centre of the moon’s orbit, and Jupiter in the centre of his system of satellites, and the sun in the centre of the planetary system, the sun would have been a body like Jupiter and the earth, that is, without light and heat, and consequently he knows no reason why there is only one body qualified to give light and heat to all the rest, but because the Author of the system thought it convenient, and because one was sufficient to warm and enlighten all the rest. To the second query of Dr. Bentley, he replies that the motions which the planets now have could not spring from any natural cause alone, but were impressed by an intelligent Agent. “To make such a system with all its motions required a cause which understood and compared together the quantities of matter in the several bodies of the sun and planets, and the gravitating powers resulting from thence; the several distances of the primary planets from the sun, and of the secondary ones from Saturn, Jupiter, and the earth, and the velocities with which those planets could revolve about those quantities of matter in the central bodies; and to compare and adjust all these things together in so great a variety of bodies, argues that cause to be not blind and fortuitous, but very well skilled in mechanics and geometry.”