26. When these words are used, as above, to express simple apprehension, they are followed by a noun in the accusative or objective case, which signifies the object conceived; as, I conceive an Egyptian pyramid. This implies no judg

ment.

27. But there is another and a very different meaning of those words, so common and so well authorized in language, that it cannot easily be avoided; and, on that account, we ought to be the more on our guard, that we be not misled by the ambiguity.

Illus. Politeness and good-breeding lead men, on most occasions, to express their opinions with modesty, especially when they differ from others whom they respect. Therefore, when a man would express his opinion modestly, instead of saying, "This is my opinion,"

or,

This is my judgment," which has the air of dogmaticalness, he says, "I conceive it to be thus, I imagine, or I apprehend, it to be thus," which is understood as a modest judgment. In like manner, when any thing is said which we take to be impossible, we say, "We cannot conceive how it could be," thereby intimating, that we cannot believe it.

28. But when the words conceive, imagine, or apprehend, are used to express opinion or judgment, they are commonly followed by a verb in the infinitive mood; as, I conceive the Egyptian pyramids to be the most ancient monuments of human art.

Illus. This implies judgment. When the words are used in this last sense, the thing conceived must be a proposition, because judgment cannot be expressed but by a proposition. When they are used in the first sense (26.), the thing conceived may be no proposition, but a simple term only; as a pyramid, an obelisk. Yet even a proposition may be simply apprehended, without forming any judgment of its truth or falsehood; for it is one thing to conceive the meaning of a proposition; it is another thing to judge it to be true or false.

29. Most of the operations of mind, from their very nature, must have objects to which they are directed, and about which they are employed. He that perceives must perceive something; and that which he perceives is called the object of his perception.

Corol. It is, therefore, impossible to perceive without having some object of perception. The mind that perceives, the object perceived, and the operation of perceiving that object, are distinct things, and are distinguished in the structure of all languages.

30. In this sentence, I see, or perceive the moon; I is the person or mind; the active verb see, denotes the operation of that mind; and the moon denotes the object.

31. What we have said of perceiving, is equally applicable to most operations of mind, which are, in all languages, expressed by active transitive verbs; and such verbs require an agent and an object.

Corol. Whence it is evident, that all mankind, both those who have contrived language, and those who use it with understanding, have distinguished these three things as different; to wit, the operations of the mind, which are expressed by active verbs, the mind itself, which is the nominative to those verbs; and the object, which is the oblique case governed by them.

32. The word idea, in popular language, signifies precisely the same thing that we commonly express by the active participles conceiving or apprehending.

Illus. 1. Thus, to have an idea of a thing, is to conceive it. To have a distinct idea of it, is to conceive it distinctly. To have no idea of it, is not to conceive it at all.

2. Idea, therefore, signifies the same thing as conception, apprehension, notion.

33. When the word idea is taken in this popular sense, no man can possibly doubt whether he has ideas; for he that doubts must think, and to think is to have ideas.

34. The term idea, coming from the Greek verb idεw, properly signifies a thought, representative of such objects as have been perceived by the sense of sight.

Obs. It is solely owing to the poverty of language that this word is also used for the notions which we have of things received by means of the other senses; and, further still, to those primary notions or elements of abstract thought, which compose trains of argument and chains of reasoning, in the mind of the philosopher or

the statesman.

35. When, therefore, in common language, we speak of having an idea of any thing, we mean no more by that expression than to conceive of it.

Illus. But as we cannot conceive, or have a notion of any thing, without thinking of it, to constitute an idea implies a mind that thinks; an act of the mind which we call thinking; and an object about which we think.

36. The word idea, however, in a philosophical sense, means some image, or representative of an external object present to the mind.

Illus. 1. The idea is in the mind itself, and can have no existence but in a mind that thinks; but the remote or mediate object may be something external, as the sun or moon; it may be something past or future; it may be something which never existed; and we may observe that this meaning is built upon a philosophical opinion.

2. For, if philosophers had not believed that there are such im

mediate objects of all our thoughts in the mind, they would never have used the word idea to express them.

3. But the term idea, taken in this sense, is to be considered a mere fiction of philosophers; and use, the arbiter of language, hath now, in all popular discussions, authorized as synonyma the words thought, notion, apprehension, and idea.

37. When a figure is stamped upon a body by pressure, that figure is called an impression, as the impression of a seal on wax, or of printing-types, or of a copper-plate, on paper. This seems now to be the literal sense of the word; the effect borrowing its name from the cause.

Obs. But by metaphor or analogy, like most other words, its meaning is extended to signify any change produced in a body by the operation of some external cause. A blow of the hand makes no impression on a stone wall; but a battery of cannon may. The moon raises a tide in the ocean, but makes no perceptible impression on rivers and lakes.

38. When we speak of making an impression on the mind, the word is carried still farther from its literal meaning; use, however, which, as we have observed above, is the arbiter of language, authorizes this application of it; as when we say that admonition and reproof make little impression on those who are confirmed in bad habits. The same discourse delivered in one way makes a strong impression on the hearers; delivered in another way, it makes no impression at all.

Illus. 1. Now, in such examples, an impression made on the mind always implies some change of purpose or will; some new habit produced, or some former habit weakened; some passion raised or allayed. When such changes are produced by persuasion, example, or any external cause, we say that such causes make an impression upon the mind. But when things are seen, or heard, or apprehended, without producing any passion, or emotion, we say that they make no impression.

If

2. In the most extensive sense, an impression is a change produced in some passive subject by the operation of an external cause. we suppose an active being to produce any change in itself by its own active power, this is never called an impression. It is the act or operation of the being itself, not an impression upon it. From this it appears, that to give the name of an impression to any effect produced in the mind, is to suppose that the mind does not act at all in the production of that effect.

3. If seeing, hearing, desiring, willing, be operations of the mind, they cannot be impressions. If they be impressions, they cannot be operations of the mind. In the structure of all languages, they are considered as acts or operations of the mind itself, and the names given them imply this. To call them impressions, therefore, is to trespass against the structure, not of a particular language only, but of all languages,

Corol. The term impression, consequently, in the department of logic and mental science, merely denotes whatever produces that change in the mind which is necessary to perceive an object, or to form a thought.

39. Sensation is a name given by philosophers to an act of mind which may be distinguished from all others by this, that it hath no object distinct from the object itself.

Illus. Pain of every kind is an uneasy sensation. When I am pained, I cannot say, that the pain I feel is one thing, and that my feeling it is another thing. They are one and the same thing, and cannot be disjoined even in imagination. Pain, when it is not felt, has no existence. It can be neither greater nor less in degree, or duration, nor any thing else in kind, that it is felt to be. It cannot exist by itself, nor in any subject, but in a sentient being. No quality of any inanimate and insentient being can have the least resemblance to it.

40. What we have said of pain may be applied to every other sensation; some of them are agreeable, others uneasy, in various degrees.

Obs. These, being objects of desire or aversion, have some attention given to them; but many are indifferent, and so little attended to, that they have no name in any language.

41. Most operations of the mind, that have names in common language, are complex in their nature, and made up of various ingredients, or more simple acts; which, though conjoined in our constitutions, must be disjoined by abstraction, in order to our having a distinct and scientific notion of the complex operation. In such operations, sensation, for the most part, makes an ingredient. Those who do not attend to the complex nature of such operations, are apt to resolve them into some one of the simple acts of which they are compounded, overlooking others.

Obs. Nothing, therefore, is of so much importance as to have a distinct notion of that simple act of the mind which we call sensation, without puzzling ourselves about the particular nature of the change effected in the organ, in the nerves, or in the brain, by the secondary qualities of matter, in the process which constitutes sensation, and of which we can have no clearer knowledge than if we ourselves were not the subjects of that mysterious operation.

42. The word feeling hath two meanings.

First, It signifies the perceptions which we have of external objects, by the sense of touch. When we speak of feeling a body to be hard or soft, rough or smooth, hot or cold; to feel these things, is to perceive them by touch.

Secondly, The word feeling is used to signify the same thing as sensation, which we have just explained; and in

this sense, it has no object; the feeling and the thing felt, are one and the same.

Obs. Perhaps betwixt feeling, taken in this last sense, and sensation, there may be this small difference, that sensation is most commonly used to signify those feelings which we have by our external senses and bodily appetites, and all our bodily pains and pleasures. But there are feelings of a nobler nature accompanying our affections, our moral judgments, and our determinations in matters of taste, to which the word sensation is less properly applied.

Note. Other words that need explication, shall be explained as they occur.

43. A GENERAL rule, when applied to regulate particulars, is termed a principle; and explanations or injunctions from principle are termed theory, or system. The particulars to be explained are termed phenomena.

Obs. As there are words common to philosophers and to the unlearned, which need no explication; so there are principles common to both, which need no proof, and which do not admit of direct proof.

44. Such principles, when we have occasion to use them in science, are called axioms.

Illus. Thus, mathematicians, before they attempt to prove any proposition in mathematics, lay down certain axioms or common principles, upon which they build their reasonings. And although those axioms be truths which every man knew before; such as, "That the whole is greater than a part"-" that equal quantities added to equal quantities make equal sums;" yet, when we see nothing assumed in the proof of mathematical propositions, but such self-evident axioms, the propositions appear more certain, and leave no room for doubt or dispute.

45. In every other science, as well as in mathematics, it will be found that there are a few common principles, upon which all the reasonings in that science are grounded, and into which they may be resolved. If these principles were pointed out and explained, we should be better able to judge what stress may be laid upon the conclusions in that science. If the principles be certain, the conclusions justly drawn from them must be certain. If the principles be only probable, the conclusions can only be probable. If the princi