Imagens das páginas
PDF
ePub

explain to you the Catholic teaching concerning transubstantiation.

Phil. I suppose you mean the philosophy of the mind and of common-sense, which Dr Reid, in his Inquiry, and Dr Beattie, in his Essay on Truth, have so clearly explained, and so solidly established.

Orth. I do; and from the language of nature, explained by these learned gentlemen, I lay down the following observations, which will serve as So many principles in our present inquiry.

First, The different qualities which we observe in bodies, by means of our senses-their colour, smell, taste, and the like-are not in these bodies themselves what they are in our mind. In us they are sensations, feelings, or perceptions excited in our mind, by the mediate or immediate action of external objects upon the organs of our senses. Thus, the feeling which we have of colour, is not in the coloured body, but is excited by the rays of light reflected in a certain manner from that body, which, striking on our eyes, excite in the mind that sensation which we call colour; and, according to the different proportions in which the rays of light are reflected to our eyes, the sensations of different colours are excited. In like manner, when we taste sugar, the sweetness is not in the sugar, but is a perception or feeling excited in our mind by the particles of sugar acting upon our organ of taste when applied to it. The same observation holds true in all the sensible qualities which we perceive in bodies; and may be explained by a familiar example. When the point of a needle is pressed upon any part of our body, we experience that uneasy sensation which we call pain; now it is evident this pain is not in the needle, but is a feeling of our mind caused by the needle. So when we smell

a rose, the agreeable odour which we experience is not in the rose, but is a sensation excited in our mind by the perfume of the rose applied to our organ of smell.

Secondly, In examining objects we must carefully distinguish three things; first, the feelings or sensations excited in our minds by the actions of those objects upon our organs of sense; secondly, the particular qualities or dispositions of the objects themselves, by which they excite such feelings; and thirdly, the material part or substance of the objects, in which the particular qualities or dispositions reside.

Thirdly, A little attention to what passes in our minds will convince us that we are totally ignorant of the material part or substance of all surrounding objects; that we are no less ignorant of the nature of the particular qualities or dispositions of bodies, by which they act upon our organs, and excite certain feelings and sensations in our mind; and that all our natural knowledge of bodies is confined to their sensible qualities alone, as perceived by us. From these we argue that there are bodily objects really existing without us, and independent of us; that they have in themselves certain qualities or arrangements of their component parts, calculated to excite various sensations in us, when applied to the organs of our senses; that these qualities are different in different objects, which excite various sensations, according to their respective qualities; that these qualities may be changed in the same object, so that it shall cease to excite the sensations in us which it formerly did, and excite others which it did not raise before, &c.

Fourthly, As it is experience alone that shows us the connection between the several bodies around us, and the corresponding sensations which they excite in our minds; and as this connection is constant, we naturally

conclude that these bodies are the causes of the sensations which we feel, and being ignorant of the manner in which they produce these effects, "without inquiring farther," as Dr Reid justly observes, "we attribute to the cause some vague and indistinct notion of power or virtue to produce the effect. In many cases the purposes of life do not make it necessary to give distinct names to the cause and the effect; and hence it happens, that being closely connected in the imagination, though very unlike to each other, one name serves for both, which occasions an ambiguity in many terms in all languages. Thus magnetism signifies both the power or virtue in the loadstone to attract the iron as a cause, and the motion in the iron towards the loadstone as an effect. Heat signifies both a sensation of our mind, and a quality or state of bodies apt to excite that sensation in u's. The names of all smells, tastes, sounds, as well as heat and cold, have a like ambiguity in all languages, though, in common language, they are rarely used to signify the sensations, but generally the external qualities indicated by the sensations."

Fifthly, In like manner, this general term, the sensible qualities of bodies, is ambiguous: it signifies both that particular aptitude, power, or virtue in bodies to excite. certain sensations in our mind, when applied to our organs of sense; and also these very sensations themselves. In the former sense it signifies a thing of which we have no idea, and are totally ignorant in what it consists; in the latter, it signifies a thing with which we are thoroughly acquainted.

Sixthly, As we are totally ignorant of the nature of sensible qualities residing in the objects around us, so we are equally ignorant of the reason why they excite their corresponding sensations in our mind. We can see

no reason why the rays of light variously reflected to our eyes, should excite in us the sensations of various colours, nor why the motion of the air should excite the idea of sound, or the fire heat, or sugar sweetness, or the like. By experience we know that it is so, but why or how it is so, of this we know nothing. This we must resolve into the will of the Creator, Who has so ordered, and Who doubtless might have ordered otherwise had He so pleased.

Seventhly, Besides the sensations which external bodies excite in our mind, by our organs of sense, as the immediate objects of these organs, we also find from experience, that they produce many other sensible effects, both upon our bodies and upon each other, when applied to action. Thus ipecacuan, besides the ideas of its colour, taste, and smell, which it excites in our mind by the organs of our senses, when taken into the stomach, also produces sickness; opium allays pain, and causes sleep; wine intoxicates; and so of other things. These effects of different bodies we know by experience; but we are totally ignorant why they produce them, or what particular quality or disposition it is in each, which produces the effect proper to it. But as experience teaches us that they constantly do produce these effects, in the same circumstances, we naturally attribute to each body a quality, power, or virtue proper to itself, bestowed upon it by the Creator; and all such powers of bodies may be included under the general name of sensible qualities, because they manifest themselves to our senses by the effects which they produce.

Eighthly, If we inquire in what all these sensible. qualities of bodies consist, or what is that particular disposition of each body, by which it produces the effects proper to it, we must acknowledge our total ignorance,

and confess that we know nothing. If we suppose the original matter, which composes the substance of bodies, to be the same in all, and that it acts mechanically, which seems to be the most generally received opinion, then we can conceive no other way of accounting for the different qualities of different bodies, than by the figure, motion, and combination of the particles of matter in the structure of each.

It is true, indeed, that a difference in these things alters the sensible qualities of bodies; witness the various and opposite qualities of quicksilver, according to the various changes wrought in the structure of its component parts by fire; and it seems to be the approved opinion of philosophers, that all the vast variety of productions from the earth is owing only to the dif ferent modifications of the same nutritive juice, according to the different plants by which it is imbibed. But whether this be really the case, and holds good in all varieties of creatures—or if there be, in fact, different kinds of primitive matter, of which bodies are composed, and to which their various qualities are owing, we know not. Whether these qualities of bodies arise from the mechanical structure of their parts; or if they be the immediate effect of the divine will, impressed upon different compositions of the same original matter, by way of a law, we are entirely ignorant.

Phil. What you have said seems perfectly clear, and the substance of it may, I think, be thus summed up in a few words: the sensible effects which various bodies produce, either in ourselves, or in each other, are objects of knowledge, of which we are absolutely certain, from the testimony of our senses. From these sensible effects we justly argue the existence of the bodies which produce them; and we also infer that those bodies have in

« AnteriorContinuar »