ther fpecies of beings quite diftinct from herself. A plough-boy, that has never travelled beyond his own village, and has feen nothing but thatched houses and his parish-church, is naturally led to imagine that thatch belongs to the very nature of a house, and that must be a church which is built of ftone, and especially if it has a fpire upon it. A child whofe uncle has been exceffive fond, and his fchoolmafter very fevere, eafily believes, that fondness always belongs to uncles, and that severity is effential to mafters or inftructors. He has feen alfo foldiers with red coats, or ministers with long black gowns, and therefore he perfuades himself that thefe garbs are effential to the characters, and that he is not a minifter who has not a long black gown, nor can he be a foldier who is not dreffed in red. It would be well if all fuch mistakes ended with childhood.

It might be alfo fubjoined, that our complex ideas become confused, not only by uniting or blending together more fimple or fingle ideas, than really belong to them, as in the instances jnft mentioned; but obfcurity and confufion fometimes come upon our ideas also, for want of uniting a fufficient number of fingle ideas to make the complex one: fo if I conceive of a leopard only as a spotted beaft, this does not diftinguish it from a tyger or a lynx, nor from many dogs or horfes, which are fpotted too; and therefore a leopard must have some more ideas added to complete and diftinguish it.

I grant that it is a large and free acquaintance with the world, a watchful obfervation and diligent search into the nature of things that must fully correct this kind of errors: the rules of logic are not fufficient to do it but yet the rules of logic may inftruct us by what means to diftinguish one thing from another, and how to fearch and mark out as far as may be, the contents and limits of the nature of diftinct beings, and thus may give us great afliftance towards the remedy of these mistakes.

As the definition of names frees us from that confufion which words introduce, fo the definition of things will, in fome measure, guard us against that confusion

which mingled ideas have introduced: for as a definition of the name explains what any words means, so a definition of the thing explains what is the nature of that thing.

In order to form a definition of any thing we must put forth these three acts of the mind.

First, compare the thing to be defined with other things that are most like to itself, and see wherein its effence or nature agrees with them; and this is called the general nature or genus in a definition: fo if you would define what wine is, first compare it with other things, like itself, as cyder, perry, &c. and you will find it agrees effentially with them in this, that it is a fort of juice.

Secondly, confider the most remarkable and primary attribute, property, or idea wherein this thing differs from those other things that are most like it; and that is its effential or specific difference: fo wine differs from cyder and perry, and all other juices, in that it is preffed from a grape. This may be called its fpecial nature, which diftinguishes it from other juices.

Thirdly, join the general and special nature together, or (which is all one) the genus and the difference, and these make up a definition. So the juice of a grape, or juice preffed from grapes, is the definition of wine.

So if I would define what winter is, I confider first wherein it agrees with other things which are most like it, (viz.) fummer, fpring, autumn, and I find they are all feasons of the year; therefore a season of the year is the genus. Then I observe wherein it differs from thefe, and that is in the fhortnefs of the days; for it is this which does primarily diftinguish it from other feafons; therefore this may be called its special nature of its difference. Then by joining these together I make a definition. Winter is that season of the year wherein the days are shortest. I confefs indeed this is but a ruder definition of it; for to define it, as an accurate aftronomer, I must limit the days, hours and minutes.

After the fame manner if we would explain or define what the picture of a man is, we confider firft the genus or general nature of it, which is a reprefentation; and

herein it agrees with many other things, as a ftatue, a fhadow, a print, a verbal defcription of a man, &c. Then we confider wherein it differs from thefe, and we find it differs from a verbal description in that it is a representation to the eye and not to the car; it differs from a ftatue in that it is a reprefentation upon a flat furface, and not in a folid figure; it differs from a fhadow, in that it is an abiding representation and not a fleeting one it differs from a print or draught, because it reprefents the colours by paint as well as the fhape of the object by delineation. Now fo many or rather fo few of these ideas put together, as are just fufficient to diftinguish a picture from all other reprefentations, make up its effential difference or its fpecial nature; and all these are included in its being painted on a plain furface. Then join this to the genus, which is a reprefentation; and thus you have the complete definition of the picture of a man, (viz.) it is the reprefentation of a man in paint upon a furface (or a plane.)

Here it must be obferved, that when we fpeak of the genus and difference as compofing a definition, it must always be understood that the nearest genus and specific difference are required.

The next general nature or the nearest genus must be used in a definition, because it includes all the reft; and if I would define wine, I muft fay wine is a juice, which is the nearest genus; and not say, wine is a liquid, which is a remote general nature; or wine is a fubftance, which is yet more remote, for juice includes both fubftance and liquid. Befides, neither of these two remote general natures would make any diftinction between wine and a thousand other fubftances or other liquids, a remote genus leaves the thing too much undistinguished.

The fpecific difference is that primary attribute which diftinguishes each fpecies from one another, while they flood ranked under the fame general nature or genus. Though wine differs from other liquids in that it is the juice of a certain fruit, yet this is but a general or generic difference, for it does not diftinguifh wine from cyder or perry; the fpecific difference of wine

therefore is its preffure from the grape; as cyder is preffed from apples and perry from pears.

In definitions alfo we must use the primary attribute that diftinguishes the fpecies or fpecial nature, and not attempt to define wine by its particular taftes, or effects, or other properties, which are but fecondary or confequential, when its preffure from the grape is the moft obvious and primary diftinction of it from all other juices. I confefs in fome cafes it is not fo easily known which is the primary idea that diftinguishes one thing from another; and therefore fome would as foon define winter by the coldness of the season, as by the fhortness of the days; though the shortness of the days is doubtlefs the most juft, primary and philofophical difference betwixt that and the other feasons of the year, fince winter days are always fhorteft, but not always the coldeít; I add alfo that the fhortness of the days is one caufe of the coldnefs, but the cold is no caufe of their shortnefs.

THE

SECT. V.

Rules of the Definition of the Things.

THE fpecial rules of a good definition, are thefe Rule I. A definition must be univerfal, or as fome call it adequate; that is, it must agree to all the particular species or individuals that are included under the fame idea; fo the juice of a grape agrees to all proper wines, whether red, white, France, Spanish, Florence, &c.

Rule II. It must be proper and peculiar to the thing defined, and agree to that alone; for it is the very defign of a definition effectually to diftinguifh one thing from all others: fo the juice of a grape agrees to no other fubitance, to no other liquid, to no other being. but wine.

These two rules being obferved, will always render a

definition reciprocal with the thing defined; which is a fcholaftic way of fpeaking, to fignify that the definition may be used in any fentence in the place of the thing defined, or they may be mutually affirmed concerning each other, or fubftituted in the room of each other. The juice of the grape is wine, or wine is the juice of the grape. And wherefoever the word wine is used, you may put the juice of the grape instead of it, except when you confider wine rather as a word than a thing, or when it is mentioned in fuch logical rules.

Rule III. A definition. ought to be clear and plain; for the defign of it is to lead us into the knowledge of the thing defined.

Hence it will follow, that the words ufed in definition ought not to be doubtful, and equivocal, and obfcure, but as plain and eafy as the language will afford and indeed it is a general rule concerning the defini tion both of names and things, that no word fhould be uled in either of them, which has any darkness or difficulty in it, unlefs it has been before explained or defined.

Hence it will follow alfo that there are many things which cannot well be defined either as to the name of the thing, unless it be by fynonymous words, or by a negation of the contrary idea, &c. for learned men. know not how to make them more evident or more intelligible than the ideas which every man has gained by the vulgar methods of teaching. Such are the ideas of extenfion, duration, thought, consciousness, and most of our fimple ideas, and particularly fenfible qualities, as white, blue, red, cold, heat, fweet, bitter, four, &c.

We can fay of duration that it is a continuance in being, or a not ceafing to be; we can say of confcioufnefs, that it is as it were a feeling within ourselves; we may fay, heat is that which is not cold; or four is that which is like vinegar; or we may point to the clear fky, and fay that is blue. These are the vulgar methods of teaching the definitions of names, or meaning of words. But there are some philofophers, whofe attempts to define these things learnedly, have wrapt up their ideas in greater darkness, and expofed themselves to ridicule and contempt: as when they define heat, they