knowledge or intention. But, laying aside conjecture, and all pretences to determine in things beyond our reach, we must rest in this, that body and mind are the only kinds of being of which we can have any knowledge, or can form any conception. If there be other kinds, they are not discoverable by the faculties which God hath given us; and with regard to us, are as if they

were not.

As, therefore, all our knowledge is confined to body and mind, or things belonging to them, there are two great branches of philosophy, one relating to body, the other to mind. The properties of body, and the laws that obtain in the material system, are the objects of natural philosophy, as that word is now used. The branch which treats of the nature and operations of minds has by some been called Pneumatology. And to the one or the other of these branches, the principles of all the sciences belong.

What variety there may be of minds or thinking beings throughout this vast universe, we cannot pretend to say. We dwell in a little corner of God's dominion, disjoined from the rest of it. The globe which we inhabit is but one of seven planets that encircle our sun. What various orders of beings may inhabit the other six, their secondaries, and the comets belonging to our system; and how many other suns may be encircled with like systems, are things altogether hid from us. Although human reason and industry have discovered with great accuracy the order and distances of the planets, and the laws of their motion, we have no means of corresponding with them. That they may be the habitation of animated beings is very probable; but of the nature, or powers of their inhabitants, we are perfectly igno- rant. Every man is conscious of a thinking principle or mind in himself, and we have sufficient evidence of a like principle in other men. The actions of brute animals show, that they have some thinking principle, though of a nature far inferior to the human mind. And every thing about us may convince us of the existence of a Supreme Mind, the Maker and Governor of the universe. These are all the minds of which reason can give us any certain knowledge.

The mind of man is the noblest work of God which reason discovers to us, and therefore, on account of its dignity, deserves our study. It must indeed be acknowledged, that although it is of all objects the nearest to us, and seems the most within our reach, it is very difficult to attend to its operations, so as to form a distinct notion of them; and on that account there is no branch of knowledge in which the ingenious and speculative have fallen into so great errors, and even absurdities. These errors and absurdities have given rise to a general prejudice against all inquiries of this nature; and because ingenious men have, for many ages, given different and contradictory ac

counts of the powers of the mind, it is concluded, that all speculations concerning them are chimerical and visionary.

But whatever effect this prejudice may have with superficial thinkers, the judicious will not be apt to be carried away with it. About two hundred years ago, the opinions of men in natural philosophy were as various, and as contradictory, as they are now concerning the powers of the mind. GALILEO, TORRICELLI, KEPLER, BACON, and NEWTON, had the same discouragement in their attempts to throw light upon the material system, as we have with regard to the intellectual. If they had been deterred by such prejudices, we should never have reaped the benefit of their discoveries, which do honour to human nature, and will make their names immortal. The motto which Lord BACON prefixed to some of his writings was worthy of his genius, Inveniam viam aut faciam.

There is a natural order in the progress of the sciences, and good reasons may be assigned why the philosophy of body should be elder sister to that of mind, and of a quicker growth; but the last hath the principle of life no less than the first, and will grow up, though slowly, to maturity. The remains of ancient philosophy upon this subject, are venerable ruins, carrying the marks of genius and industry, sufficient to inflame, but not to satisfy our curiosity. In later ages, DES CARTES was the first that pointed out the road we ought to take in those dark regions. MALEBRANCHE, ARNAUD, LOCKE, BERKELEY, BUFFIER, HUTCHESON, BUTLER, HUME, PRICE, LORD KAIMES, have laboured to make discoveries; nor have they laboured in vain. For, however different and contrary their conclusions are, however skeptical some of them, they have all given new light, and cleared the way to those who shall come after them.

We ought never to despair of human genius, but rather to hope, that in time it may produce a system of the powers and operations of the human mind, no less certain than those of optics or astronomy.

This is the more devoutly to be wished, that a distinct knowledge of the powers of the mind would undoubtedly give great light to many other branches of science. Mr. HUME hath justly observed, that "all the sciences have a relation to human nature; and, however wide any of them may seem to run from it, they still return back by one passage or another. This is the centre and capitol of the sciences, which being once masters of, we may easily extend our conquests every where."

The faculties of our minds are the tools and engines we must use in every disquisition; and the better we understand their nature and force, the more successfully we shall be able to apply them. Mr. LOCKE gives this account of the occasion of his entering upon his Essay concerning Human Understanding: “Five or six friends, says he, meeting at my chamber, and dis

coursing on a subject very remote from this, found themselves quickly at a stand by the difficulties that rose on every side. After we had for a while puzzled ourselves, without coming any nearer to a resolution of those doubts that perplexed us, it came into my thoughts that we took a wrong course; and that, before we set ourselves upon inquiries of that nature, it was necessary to examine our own abilities, and see what objects our understandings were fitted or not fitted to deal with. This I proposed to the company, who all readily assented; and thereupon it was agreed that this should be our first inquiry." If this be commonly the cause of perplexity in those disquisitions which have least relation to the mind, it must be so much more in those that have an immediate connexion with it.

The sciences may be distinguished into two classes, according as they pertain to the material or to the intellectual world. The various parts of Natural Philosophy, the mechanical Arts, Chymistry, Medicine, and Agriculture, belong to the first; but, to the last, belong Grammar, Logic, Rhetoric, Natural Theology; Morals, Jurisprudence, Law, Politics, and the Fine Arts. The knowledge of the human mind is the root from which these grow, and draw their nourishment. Whether therefore we consider the dignity of this subject, or its subserviency to science in general, and to the noblest branches of science in particular, it highly deserves to be cultivated.

A very elegant writer, on the Sublime and Beautiful, concludes his account of the passions thus: "The variety of the passions is great, and worthy, in every branch of that variety, of the most diligent investigation. The more accurately we search into the human mind, the stronger traces we every where find of His wisdom who made it. If a discourse on the use of the parts of the body may be considered as a hymn to the Creator; the use of the passions, which are the organs of the mind, cannot be barren of praise to him, nor unproductive to ourselves of that noble and uncommon union of science and admiration, which a contemplation of the works of infinite Wisdom alone can afford to a rational mind; whilst referring to him whatever we find of right, or good, or fair, in ourselves, discovering his strength and wisdom even in our own weakness and imperfection, honouring them where we discover them clearly, and adoring their profundity where we are lost in our search, we may be inquisitive without impertinence, and elevated without pride; we may be admitted, if I may dare to say so, into the councils of the Almighty, by a consideration of his works. This elevation of the mind ought to be the principal end of all our studies, which, if they do not in some measure effect, they are of very little service to us."

ESSAYS

ON THE

INTELLECTUAL POWERS OF MAN.

ESSAY I.

PRELIMINARY.

CHAPTER I.

EXPLICATION OF WORDS.

THERE is no greater impediment to the advancement of knowledge than the ambiguity of words. To this chiefly it is owing that we find sects and parties in most branches of science; and disputes, which are carried on from age to age, without being brought to an issue.

Sophistry has been more effectually excluded from mathematics and natural philosophy than from other sciences. In mathematics it had no place from the beginning; mathematicians having had the wisdom to define accurately the terms they use, and to lay down, as axioms, the first principles on which their reasoning is grounded. Accordingly we find no parties among mathematicians, and hardly any disputes.

In natural philosophy, there was no less sophistry, no less dispute and uncertainty, than in other sciences, until about a century and a half ago, this science began to be built upon the foundation of clear definitions and, self-evident axioms. Since that time, the science, as if watered with the dew of heaven, hath grown apace; disputes have ceased, truth hath prevaled, and the science hath received greater increase in two centuries, than in two thousand years before.

It were to be wished, that this method, which hath been so successful in those branches of science, were attempted in others for definitions and axioms are the foundations of all science. But that definitions may not be sought, where no definition can be given, nor logical definitions be attempted, where the subject does not admit of them, it may be proper to lay down some general principles concerning definition, for the sake of those who are less conversant in this branch of logic.

When one undertakes to explain any art or science, he will have occasion to use many words that are common to all who use the same language, and some that are peculiar to that art or science. Words of the last kind are called terms of the art, and ought to be distinctly explained, that their meaning may be understood.

A definition is nothing else but an explication of the meaning of a word, by words whose meaning is already known. Hence it is evident, that every word cannot be defined; for the definition must consist of words; and there could be no definition, if there were not words previously understood without definition. Common words, therefore, ought to be used in their common acceptation; and, when they have different acceptations in common language, these, when it is necessary, ought to be distinguished. But they require no definition. It is sufficient to define words that are uncommon, or that are used in an uncommon meaning.

It may farther be observed, that there are many words, which, though they may need explication, cannot be logically defined. A logical definition, that is, a strict and proper definition, must express the kind of the thing defined, and the specific difference, by which the species defined, is distinguished from every other species belonging to that kind. It is natural to the mind of man to class things under various kinds, and again to subdivide every kind into its various species. A species may often be subdivided into subordinate species, and then it is considered as a kind.

From what has been said of logical definition, it is evident, that no word can be logically defined which does not denote a species; because such things only can have a specific difference; and a specific difference is essential to a logical definition. On this account there can be no logical definition of individual things, such as London or Paris. Individuals are distinguished either by proper names, or by accidental circumstances of time or place, but they have no specific difference; and therefore, though they may be known by proper names, or may be described by circumstances or relations, they cannot be defined. It is no less evident, that the most general words cannot be logically defined, because there is not a more general term of which they are a species.