For True and False are attributes of Speech, not of things.

And where Speech in not, there is neither Truth nor Falshood.
Errour there may be, as when wee expect that which shall not be; or suspect what has not been: but in neither case can a man be charged with Untruth.
Seeing then that Truth consisteth in the right ordering of names in our affirmations, a man that seeketh precise Truth, had need to remember what every name he uses stands for; and to place it accordingly; or els he will find himselfe entangled in words, as a bird in lime-twiggs; the more he struggles, the more belimed.

And therefore in Geometry, (which is the onely Science that it hath pleased God hitherto to bestow on mankind,) men begin at settling the significations of their words; which settling of significations, they call Definitions; and place them in the beginning of their reckoning.
By this it appears how necessary it is for any man that aspires to true Knowledge, to examine the Definitions of former Authors; and either to correct them, where they are negligently set down; or to make them himselfe.

For the errours of Definitions multiply themselves, according as the reckoning proceeds; and lead men into absurdities, which at last they see, but cannot avoyd, without reckoning anew from the beginning; in which lyes the foundation of their errours.

From whence it happens, that they which trust to books, do as they that cast up many little summs into a greater, without considering whether those little summes were rightly cast up or not; and at last finding the errour visible, and not mistrusting their first grounds, know not which way to cleere themselves; but spend time in fluttering over their bookes; as birds that entring by the chimney, and finding themselves inclosed in a chamber, flitter at the false light of a glasse window, for want of wit to consider which way they came in.