But whatever inconvenience follows from this mistake of words, this I am sure, that, by constant and familiar use, they charm men into notions far remote from the truth of things.  It would be a hard matter to persuade any one that the words which his father, or schoolmaster, the parson of the parish, or such a reverend doctor used, signified nothing that really existed in nature:  which perhaps is none of the least causes that men are so hardly drawn to quit their mistakes, even in opinions purely philosophical, and where they have no other interest but truth.  For the words they have a long time been used to, remaining firm in their minds, it is no wonder that the wrong notions annexed to them should not be removed.

17.  Fifthly, by setting them in the place of what they cannot signify.

V. Fifthly, Another abuse of words is, the setting them in the place of things which they do or can by no means signify.  We may observe that, in the general names of substances, whereof the nominal essences are only known to us, when we put them into propositions, and affirm or deny anything about them, we do most commonly tacitly suppose or intend, they should stand for the real essence of a certain sort of substances.  For, when a man says gold is malleable, he means and would insinuate something more than this, That what I call gold is malleable, (though truly it amounts to no more,) but would have this understood, viz.  That gold, i.e. what has the real essence of gold, is malleable; which amounts to thus much, that malleableness depends on, and is inseparable from the real essence of gold.  But a man, not knowing wherein that real essence consists, the connexion in his mind of malleableness is not truly with an essence he knows not, but only with the sound gold he puts for it.  Thus, when we say that animal rationale is, and animal imflume bipes latis unguibus is not a good definition of a man; it is plain we suppose the name man in this case to stand for the real essence of a species, and would signify that ‘a rational animal’ better described that real essence than ’a two-legged animal with broad nails, and without feathers.’  For else, why might not Plato as properly make the word [word in Greek], or man, stand for his complex idea, made up of the idea of a body, distinguished from others by a certain shape and other outward appearances, as Aristotle make the complex idea to which he gave the name [word in Greek], or man, of body and the faculty of reasoning joined together; unless the name [word in Greek], or man, were supposed to stand for something else than what it signifies; and to be put in the place of some other thing than the idea a man professes he would express by it?

18.  VI.  Putting them for the real Essences of Substances.