seem to be formed, much upon the same grounds, as our judgments of the Identity of other persons besides the selfidentity which we have of ourselves.

Illus. 1. Wherever there is great similarity, we are apt to presume Identity, if no reason appears to the contrary: when two objects, ever so like, are perceived at the same time, they cannot be the same. But if they are presented to our senses at different times, we are apt to think them the same, merely from their similarity.

2. Whether this is a natural prejudice, or from what cause soever it proceeds, it certainly appears in children from infancy; and when they grow up, it is confirmed, in most instances, by experience; for, of the same species, men rarely find two individuals that are not distinguishable by obvious differences.

Example. A man challenges a thief whom he finds in possession of his horse or his watch, only on similarity. When the watch-maker swears, that he sold this watch to such a person, his testimony is grounded on similarity. The testimony of witnesses to the identity of a person, is commonly grounded on no better evidence.

Corol. Thus it appears, that the evidence we have of our own Identity, as far back as we remember, is totally of a different kind from the evidence we have of the Identity of other persons, or of objects of sense. The first is grounded on memory, and gives undoubted certainty: the last is grounded on similarity, and on other circumstances, which, in many cases, are not so decisive as to leave no room for doubt.

404. The Identity of objects of sense is never perfect, because, as they consist of parts, which, from a variety of causes, are subject to continual changes, the substances of which they are made up, are insensibly changing, increasing, or diminishing.

Illus. Thus we say of an old regiment, the 42d, for example, that it scaled the heights of Abraham at Quebec, though there now is not a man alive that belonged to it then. Also, a ship of war, which has successively changed her anchors, her tackle, her sails, her masts, her planks, and her timbers; while she keeps the same name, is still the same.

Corol. 1. The Identity, therefore, which we ascribe to bodies, whether natural or artificial, is not perfect Identity; it is rather something, which, for the conveniency of speech, we call Identity. It admits of great change of the subject, providing the change be gradual, sometimes even of a total change; as that of my countryman's pistol, which, with a new stock, a new lock, and a new barrel, was still his old pistol.

2. And the changes, which, in common language, are made consistently with Identity, differ from those that are thought to destroy it, not in kind, but in number and degree. It has no fixed nature when applied to bodies; and questions about the Identity of a body are very often questions about words. But Identity, when applied to persons, has no ambiguity, and admits not of degrees, or of more

or less. It is the foundation of all rights and obligations, and of all accountableness; and the notion of it is fixed and precise.

CHAPTER VI.

OF THE TRAIN OF THOUGHT IN THE MIND.

405. EVERY man is conscious of a Succession of Thoughts which pass in his mind while he is awake, even when they are not excited by external objects.

Obs. The mind on this account has been compared to liquor in the state of fermentation. When it is not in this state, being once at rest, it remains at rest, until it is moved by some external impulse or internal prompter. But, in the state of fermentation, it has some cause of motion in itself, which, even when there is no impulse from without, suffers it not to be at rest a moment, but produces a constant motion and ebullition, while it continues to ferment.

406. There is surely no similitude between motion and Thought; but there is an analogy, so obvious to all men, that the same words are often applied to both; and many modifications of Thought have no name but such as is borrowed from the modifications of motion. (See Art. 223. and 238. Illus. 1. and 2.)

Obs. 1. Many Thoughts are excited by the senses. The causes or occasions of these may be considered as external: but, when such external causes do not operate upon us, we continue to think from some internal cause. From the constitution of the mind itself there is a constant ebullition of Thought, a constant intestine motion; not only of Thoughts barely speculative, but of sentiments, passions and affections, which attend them. (See Art. 224. Illus.)

2. This continued succession of Thought has, by some philosophers, been called the imagination. It was formerly called the fancy, or the phantasy. If the old name be laid aside, it were to be wished that a name were given to it, less ambiguous than that of Imagination, a name which has two or three meanings besides. (Art. 259. Obs. 1. and 2. and Art. 141.)

3. It is often called the train of ideas. This may lead one to think, that it is a train of bare conceptions; but this would surely be a mistake. It is made up of many other operations of mind, as well as of conceptions, or ideas. (Art. 200.)

Example. Memory, judgment, reasoning, passions, affections and purposes; in a word, every operation of the mind (excepting those of sense) is exerted occasionally in this Train of Thought, and has its share as an ingredient; so that we must take the word idea in a

very extensive sense, if we make the Train of our Thoughts to be only a Train of Ideas. (See Art. 36. Illus. 1, 2, and 3.)

. 407. To pass from the name, and consider the thing, we may observe, that the TRAINS OF THOUGHT in the mind are of two kinds:

First, they are either such as flow spontaneously, like water from a fountain, without any exertion of a governing principle to arrange them. (Art. 202.)

Or, secondly, they are regulated and directed by an active effort of the mind, with some view and intention. (Art. 203. and 224.)

Obs. Before we consider these in their order, it is proper to premise, that these two kinds, how distinct soever in their nature, are for the most part mixed, in persons awake and come to years of understanding. (See Art. 199.)

Illus. 1. On the one hand, we are rarely so vacant of all project and design, as to let our Thoughts take their own course, without the least check or direction: or if at any time we should be in this state, some object will present itself, which is too interesting not to engage the attention, and rouse the active or contemplative powers that were at rest. (Art. 201.)

2. On the other hand, when a man is giving the most intense application to any speculation, or to any scheme of conduct, when he wishes to exclude every Thought that is foreign to his present purpose; such Thoughts will often impertinently intrude upon him, in spite of his endeavours to the contrary, and occupy, by a kind of violence, some part of the time destined to another purpose. One man may have the command of his Thoughts more than another man, and the same man, more at one time than at another: but I apprehend, that in the best trained mind, the Thoughts will sometimes be restive, sometimes capricious and self-willed, even when it is wished to have them most under command.

408. We must ascribe to Him who made us, and not to the mind, the power of calling up any Thought at pleasure, because such a call or volition supposes that Thought to be already in the mind; for otherwise, how should it be the object of volition? As this must be granted on the one hand, so it is no less certain on the other, that a man has a considerable power in regulating and disposing his own Thoughts. Of this every man is conscious, and I can no more doubt of it, than I can doubt whether I think now, as I was obliged to think when I wrote the Illustration to Article 90.

Illus. 1. We seem to treat the Thoughts that present themselves to the Fancy in crowds, as a great man treats the persons who attend his levee. They are all ambitious of his attention; he goes round the circle, bestowing a bow upon one, a smile upon another; asks a short question of a third; while a fourth is honoured with a particu

bar conference; and the greater part have no particular mark of attention, but go as they came. It is true, he can give no mark of his attention to those who were not there, but he has a sufficient number for making a choice and distinction.

2. In like manner, a number of Thoughts present themselves to the Fancy spontaneously; but if we pay no attention to them, if we hold no conference with them, they pass with the crowd, and are immediately forgotten, as if they had never appeared. But those to which we think proper to pay attention, may be stopped, examined, and arranged, for any particular purpose which we have in view. (See Chap. VI. Book 1.)

409. It may likewise be observed, that a Train of Thought, which was at first composed by application and judgment, when it has been often repeated, and becomes familiar, will present itself spontaneously. Thus, when a man has composed an air in music, so as to please his own ear-after he has played, or sung it often-the notes will arrange themselves in just order; and it requires no effort to regulate their succession. (See Art. 136. and Art. 128. Illus.)

Illus. Thus we see, that the Fancy is made up of Trains of Thinking; some of which are spontaneous, others studied and regulated; and the greater part are mixed of both kinds, and take their denomination from that which is most prevalent: and that a Train of Thought, which at first was studied and composed, may by habit present itself spontaneously. (See Art. 130.)

I. Of spontaneous Trains of Thought.

410. When the work of the day is over, and a man lies down to relax his body and mind, he cannot cease from Thinking, though he desire it. Something occurs to his Fancy; that is followed by another thing, and so his Thoughts are carried on from one object to another, until sleep closes the scene.

Illus. In this operation of the mind, it is not one faculty only that is employed; there are many that join together in its production. Sometimes the transactions of the day are brought upon the stage, and acted over again, as it were, upon this theatre of the Imagination. In this case, Memory surely acts the most considerable part, since the scenes exhibited are not fictions, but realities, which are remembered; yet in this case the Memory does not act aloneother powers are employed, and attend upon their proper objects. The transactions remembered will be more or less interesting; and we cannot then review our own conduct, nor that of others, without passing some judgment upon it. This we approve, that we disapprove, Art. 355.) This elevates, that humbles and depresses us, (Art. 359.) Persons that are not absolutely indifferent to us, can hardly appear, even to the Imagination, without some friendly or unfriendly emotion, (Art. 360.) We judge and reason about

things, as well as persons in such reveries. We remember what a man said and did; from this we pass to his designs, and to his general character, and frame some hypothesis to make the whole consistent. Such Trains of Thought we may call Historical. (See Example, Art. 359.)

411. There are others which we may call romantic, in which the plot is formed by the creative power of Fancy, without any regard to what did or what will happen. In these also, the powers of judgment, taste, moral sentiment, as well as the passions and affections, come in and take a share in the execution. (See Art. 264. Illus. 1. and 2.)

Mus. 1. In these scenes, the man himself commonly acts a very distinguished part, and seldom does any thing that he does not approve. Here the miser will be generous, the coward brave, and the knave honest. Mr. Addison, in the Spectator, calls this play of the Fancy, castle-building.

2. A castle-builder, in his fictitious scenes, will figure, not according to his real character, but according to the highest opinion he has been able to form of himself, and perhaps far beyond that opinion. For in those imaginary conflicts the passions easily yield to reason, and a man exerts the noblest efforts of virtue and magnanimity, with the same ease, as, in his dreams, he flies through the air, or plunges to the bottom of the ocean.

412. The Romantic scenes of Fancy are most commonly the occupation of young minds, not yet so deeply engaged in life as to have their Thoughts taken up by its real cares and business. (See Art. 275. and 269.)

Illus. 1. Those active powers of the mind, which are most luxuriant by constitution, or have been most cherished by education, impatient to exert themselves, hurry the Thought into scenes that give them play; and the boy commences in Imagination, according to the bent of his mind, a general or a statesman, a poet or an orator. (See Art. 276.)

2. When the Fair Ones become castle-builders, they use different materials; and while the young soldier is carried into the field of Mars, where he pierces the thickest squadrons of the enemy, despising death in all its forms; the gay and lovely nymph, whose heart has never felt the tender passion, is transported into a brilliant assembly, where she draws the attention of every eye, and makes an impression on the noblest heart.

3. But no sooner has Cupid's arrow found its way into her heart, than the whole scenery of her Imagination is changed. Balls and assemblies have now no charms. Woods and groves, the flowery bank and the crystal fountain, are the scenes she frequents in Imagination. She becomes an Arcadian shepherdess, feeding her bleating flock beside that of her Strephon, and wishes for nothing more to complete her present happiness.

4. In a few years the love-sick maid is transformed into the solicitous mother. Her smiling offspring play around her. She views