Excerpt from Thomas Hobbes, Leviathan, chapter 46: “Of Darkness from Vain Philosophy.”

That which is now called a University is a joining together, and an incorporation under one government, of many public schools in one and the same town or city, in which the principal schools were ordained for the three professions; that is to say, of the Roman religion, of the Roman law, and of the art of medicine. And for the study of philosophy it hath no otherwise place than as a handmaid to the Roman religion: and since the authority of Aristotle is only current there, that study is not properly philosophy (the nature whereof dependeth not on authors), but Aristotelity. And for geometry, till of very late times it had no place at all, as being subservient to nothing but rigid truth. And if any man by the ingenuity of his own nature had attained to any degree of perfection therein, he was commonly thought a magician, and his art diabolical.

Now to descend to the particular tenets of vain philosophy, derived to the Universities, and thence into the Church, partly from Aristotle, partly from blindness of understanding; I shall first consider their principles. There is a certain philosophia prima on which all other philosophy ought to depend; and consisteth principally in right limiting of the significations of such appellations, or names, as are of all others the most universal; which limitations serve to avoid ambiguity and equivocation in reasoning, and are commonly called definitions; such as are the definitions of body, time, place, matter, form, essence, subject, substance, accident, power, act, finite, infinite, quantity, quality, motion, action, passion, and diverse others, necessary to the explaining of a man's conceptions concerning the nature and generation of bodies. The explication (that is, the settling of the meaning) of which, and the like terms, is commonly in the Schools called metaphysics; as being a part of the philosophy of Aristotle, which hath that for title. But it is in another sense; for there it signifieth as much as "books written or placed after his natural philosophy": but the Schools take them for books of supernatural philosophy: for the word metaphysics will bear both these senses. And indeed that which is there written is for the most part so far from the possibility of being understood, and so repugnant to natural reason, that whosoever thinketh there is anything to be understood by it must needs think it supernatural.

From these metaphysics, which are mingled with the Scripture to make School divinity, we are told there be in the world certain essences separated from bodies, which they call abstract essences, and substantial forms; for the interpreting of which jargon, there is need of somewhat more than ordinary attention in this place. Also I ask pardon of those that are not used to this kind of discourse for applying myself to those that are. The world (I mean not the earth only, that denominates the lovers of it "worldly men," but the universe, that is, the whole mass of all things that are) is corporeal, that is to say, body; and hath the dimensions of magnitude, namely, length, breadth, and depth: also every part of body is likewise body, and hath the like dimensions; and consequently every part of the universe is body, and that which is not body is no part of the universe: and because the universe is all, that which is no part of it is nothing, and consequently nowhere. Nor does it follow from hence that spirits are nothing: for they have dimensions and are therefore really bodies; though that name in common speech be given to such bodies only as are visible or palpable; that is, that have some degree of opacity: but for spirits, they call them incorporeal, which is a name of more honour, and may therefore with more piety be attributed to God Himself; in whom we consider not what attribute expresseth best His nature, which is incomprehensible, but what best expresseth our desire to honour Him.

To know now upon what grounds they say there be essences abstract, or substantial forms, we are to consider what those words do properly signify. The use of words is to register to ourselves, and make manifest to others, the thoughts and conceptions of our minds. Of which words, some are the names of the things conceived; as the names of all sorts of bodies that work upon the senses and leave an impression in the imagination: others are the names of the imaginations themselves; that is to say, of those ideas or mental images we have of all things we see or remember: and others again are names of names, or of different sorts of speech; as universal, plural, singular, are the names of names; and definition, affirmation, negation, true, false, syllogism, interrogation, promise, covenant, are the names of certain forms of speech. Others serve to show the consequence or repugnance of one name to another; as when one saith, "a man is a body," he intendeth that the name of body is necessarily consequent to the name of man, as being but serval name of the same thing, man; which consequence is signified by coupling them together with the word is. And as we use the verb is; so the Latins use their verb est, and the Greeks their esti through all its declinations. Whether all other nations of the world have in their several languages a word that answereth to it, or not, I cannot tell; but I am sure they have not need of it: for the placing of two names in order may serve to signify their consequence, if it were the custom (for custom is it that gives words their force), as well as the words is, or be, or are, and the like.

And if it were so, that there were a language without any verb answerable to est, or is, or be; yet the men that used it would be not a jot the less capable of inferring, concluding, and of all kind of reasoning, than were the Greeks and Latins. But what then would become of these terms, of entity, essence, essential, essentiality, that are derived from it, and of many more that depend on these, applied as most commonly they are? They are therefore no names of things; but signs, by which we make known that we conceive the consequence of one name or attribute to another: as when we say, "a man is a living body," we mean not that the man is one thing, the living body another, and the is, or being, a third; but that the man and the living body is the same thing, because the consequence, "If he be a man, he is a living body," is a true consequence, signified by that word is. Therefore, to be a body, to walk, to be speaking, to live, to see, and the like infinitives; also corporeity, walking, speaking, life, sight, and the like, that signify just the same, are the names of nothing; as I have elsewhere more amply expressed.