most lively thought is ftill inferior to the dulleft fenfation.

WE may observe a like diftinction to run thro' all the other perceptions of the mind. A man, in a fit of anger, is actuated in a very different manner from one who only thinks of that emotion. If you tell me, that any perfon is in love, I eafily understand your meaning, and form a just conception of his fi tuation; but never can mistake that conception for the real diforders and agitations of the paffion. When we reflect on our past fentiments and affections, our thought is a faithful mirror, and copies its objects truly; but the colours it employs are faint and dull, in comparison of those in which our original perceptions were cloth'd. It requires no nice difcernment nor metaphyfical head to mark the diftinction betwixt them.

HERE therefore we may divide all the perceptions of the mind into two claffes or fpecies, which are diftinguish'd by their different degrees of force and vivacity. The lefs forcible and lively are commonly denominated THOUGHTS OF IDEAS. The other fpe. cies want a name in our language, and in most others; I fuppofe, because it was not requifite for any, but philofophical purposes, to rank them under a general term or appellation. Let us, therefore, use a little freedom, and call them IMPRESSIONS, employ

ing

ing that word in a fenfe fomewhat different from the ufual. By the term impreffion, then, we mean all our more lively perceptions, when we hear, or fee, or feel, or love, or hate, or defire, or will. And impreffions are diflinguifh'd from ideas, which are the lefs lively perceptions of which we are conscious when we reflect on any of those fenfations or move ments above mention'd.

NOTHING, at firit view, may feem more unbounded than the thought of man, which not only escapes all human power and authority, but is not even reftrain'd within the limits of nature and reality. To form monsters, and join incongruous fhapes and appearances, cofts it no more trouble than to conceive the most natural and familiar objects. And while the body is confin'd to one planet, along which it creeps with pain and difficulty; the thought can in an inftant transport us into the moft diftant regions of the universe; or even beyond the universe, into the unbounded chaos, where nature is fuppos'd to lie in total confufion. What never was feen, nor heard of, may yet be conceiv'd; nor is any thing beyond the power of thought, except what implies an abfolute contradiction,

BUT tho' thought feems to poffefs this unbounded liberty, we shall find, upon a nearer examination, that it is really confined within very narrow limits,

and

and that all this creative power of the mind amounts to no more than the compounding, tranfpofing, augmenting, or diminishing the materials afforded us by the fenfes and experience. When we think of a golden mountain, we only join two confiftent ideas, gold, and mountain, with which we were formerly acquainted. A virtuous horse we can conceive; because, from our own feeling, we can conceive vir. tue, and this we may unite to the figure and shape of a horse, which is an animal familiar to us. In short, all the materials of thinking are deriv'd either from our outward or inward fentiment: The mixture and compofition of these belongs alone to the mind and will. Or, to express myself in philofophical language, all our ideas or more feeble perceptions are copies of our impreffions or more lively ones.

To prove this, the two following arguments will, I hope, be fufficient. First, When we analyse our thoughts or ideas, however compounded or fublime, we always find, that they resolve themselves into fuch fimple ideas as were copy'd from a precedent feeling or fentiment. Even those ideas, which, at first view, seem the most wide of this origin, are found, upon a narrower fcrutiny, to be deriv'd from it. The idea of God, as meaning an infinitely intelligent, wife, Being, arifes from reflecting on the opera

own mind, and augmenting, without li

mit,

mit, thofe qualities of goodness and wisdom. We may prosecute this enquiry to what length we please ; where we shall always find, that every idea we examine is copy'd from a fimilar impreffion. Those who would affert, that this pofition is not abfolutely univerfal and without exception, have only one, and that an easy method of refuting it, by producing that idea, which, in their opinion, is not deriv'd from this fource. It will then be incumbent on us, if we would maintain our doctrine, to produce the impres fion or lively perception, which corresponds to it.

SECONDLY. If it happen, from a defect of the organ, that a man is not susceptible of any species of fenfation, we always find, that he is as little fufceptible of the correfpondent ideas. A blind man can form no notion of colours; a deaf man of founds. Restore either of them that fenfe, in which he is deficient; by opening this new inlet for his fenfations, you alfo open an inlet for the ideas, and he finds no difficulty of conceiving these objects. The cafe is the fame, if the object, proper for exciting any senfation, has never been applied to the organ. A Laplander or Negro has no notion of the relish of wine And tho' there are few or no instances of a like deficiency in the mind, where a perfon has never felt or is altogether incapable of a fentiment or paffion, that belongs to his fpecies; yet we find the fame obferva

'Tis readily

many fenfes,

tion to take place in a leffer degree. A man of mild manners can form no notion of inveterate revenge or cruelty; nor can a selfish heart eafily conceive the heights of friendship and generofity. allow'd, that other beings may poffefs of which we can have no conception; because the ideas of them have never been introduc'd to us in the only manner by which an idea can have access to the mind, viz. by the actual feeling and fenfation.

THERE is, however, one contradictory phænomenon, which may prove, that 'tis not abfolutely impoffible for ideas to go before their correspondent impreflions. I believe it will readily be allow'd, that the feveral diftinct ideas of colours, which enter by the eyes, or those of sounds, which are convey'd by the hearing, are really different from each other; tho', at the fame time, refembling. Now if this be true of different colours, it must be no less so, of the different fhades of the fame colour; and each fhade produces a diftin&t idea, independent of the reft. For if this fhould be deny'd, 'tis poffible, by the continual gradation of fhades, to run a colour infenfibly into what is most remote from it; and if you will not allow any of the means to be different, you cannot, without abfurdity, deny the extremes to be the fame. Suppofe, therefore, a perfon to have enjoy'd his fight for thirty years, and to have become perfectly well acquainted