ABSTRACT
I Am very sensible how nice and difficult a Business I undertake, in attempting to treat of the common Affections and Properties of Magnitude, which occur to Experience, and consequently afford matter for Mathematical Hypothesis, and therefore I cannot but speak something by “Way of Preface and Premonition. For there are Things, which it is very difficult not to render more perplexed by explaining, not to obscure by illustrating; Things for the most Part of so subtle and abstract a Nature, that the Imagination scarce can comprehend them, scarce can assign to each their just Bounds, or separate one from another, and consequently do elude the most piercing Sagacity, and fly away and escape him who endeavours distinctly to catch at their vanishing Ideas: So that what St. Augustine is reported to have said of Time, may not undeservedly be applied to most of them. If none seek of me what Time is, I know; If any ask me I don’t know. For what ex. gr. is Extension? What Space? What Motion? Every one, that speaks of there, imagines himself to be clearly understood, even by the most Vulgar; but if you examine their Breasts, you will find most of them linked in inextricable Snares, hesitating in their Thoughts, and entangled in their Speech. Nay, the most subtle Philosophers, after the most diligent Contemplation with the exactest Care imaginable, when they come to discourse of there Things can hardly speak consitently, either one with another, or the same with themselves: and feldom do any handle them so, but monstrous Paradoxes, and most grievous Difficulties, seem to follow.
