"It is said, that the minutest Errors are not to be neglected in Mathematics: that the Fluxions are...not proportional to the finite Increments though ever so small; but only to. . . nascent Increments. . . And. . . there be other Fluxions, which Fluxions of Fluxions are called second Fluxions. And the Fluxions of these sec- ond Fluxions are called third Fluxions: and so on, fourth, fifth, sixth, &c. ad in- finitum. Now as our Sense is strained and puzzled with the perception of Objects extremely minute, even so the Imagination, which Faculty derives from Sense, is very much strained and puzzled to frame clear Ideas of the least Particles of time, or the least Increments generated therein. . And it seems. . to. . . exceed, if I mistake not, all Humane Understanding. The further the Mind analyseth and pursueth these fugitive Ideas, the more it is lost and bewildered; the Objects, at first fleeting and minute, soon vanishing out of sight. Certainly in any Sense a second or third Fluxion seems an obscure Mystery. The incipient Celerity of an incipient Celerity, the nascent Augment of a nascent Augment, i.e. of a thing which hath no Magnitude: ‘Take it in which light you please, the clear Conception of it will, if I mistake not, be found impossible. . And if a second Fluxion be inconceivable, what are we to think of third, fourth, fifth Fluxions, and so onward without end? ... They suppose finite Quantities to consist of Parts infinitely little... Now to conceive a Quantity infinitely small, that is, infinitely less than any sensible or imaginable Quantity, or any the least finite Magnitude, is, I confess, above my Capacity. But to conceive a Part of such infinitely small Quantity, that shall be still infinitely less than it, and consequently though multiply’d infinitely shall never equal the minutest finite Quantity, is, I suspect, an infinite Difficulty to any Man whatsoever; and will be allowed such by those who candidly say what they think; provided they really think and reflect, and do not take things upon trust."