Dialogue IIIHYL. What say you to this? Since, according to you, men judge of the reality of things by their senses, how can a man be mistaken in thinking the moon a plain lucid surface, about a foot in diameter; or a square tower, seen at a distance, round; or an oar, with one end in the water, crooked?

PHIL. He is not mistaken with regard to the ideas he actually perceives, but in the inference he makes from his present perceptions. Thus, in the case of the oar, what he immediately perceives by sight is certainly crooked; and so far he is in the right. But if he thence conclude that upon taking the oar out of the water he shall perceive the same crookedness; or that it would affect his touch as crooked things are wont to do: in that he is mistaken. In like manner, if he shall conclude from what he perceives in one station, that, in case he advances towards the moon or tower, he should still be affected with the like ideas, he is mistaken. But his mistake lies not in what he perceives immediately, and at present, (it being a manifest contradiction to suppose he should err in respect of that) but in the wrong judgment he makes concerning the ideas he apprehends to be connected with those immediately perceived: or, concerning the ideas that, from what he perceives at present, he imagines would be perceived in other circumstances. The case is the same with regard to the Copernican system. We do not here perceive any motion of the earth: but it were erroneous thence to conclude, that, in case we were placed at as great a distance from that as we are now from the other planets, we should not then perceive its motion.

HYL. I understand you; and must needs own you say things plausible enough. But, give me leave to put you in mind of one thing. Pray, Philonous, were you not formerly as positive that Matter existed, as you are now that it does not?

PHIL. I was. But here lies the difference. Before, my positiveness was founded, without examination, upon prejudice; but now, after inquiry, upon evidence.

HYL. After all, it seems our dispute is rather about words than things. We agree in the thing, but differ in the name. That we are affected with ideas FROM WITHOUT is evident; and it is no less evident that there must be (I will not say archetypes, but) Powers without the mind, corresponding to those ideas. And, as these Powers cannot subsist by themselves, there is some subject of them necessarily to be admitted; which I call MATTER, and you call SPIRIT. This is all the difference.

PHIL. Pray, Hylas, is that powerful Being, or subject of powers, extended?

HYL. It hath not extension; but it hath the power to raise in you the idea of extension.

PHIL. It is therefore itself unextended?

HYL. I grant it.

PHIL. Is it not also active?

HYL. Without doubt. Otherwise, how could we attribute powers to it?

PHIL. Now let me ask you two questions: FIRST, Whether it be agreeable to the usage either of philosophers or others to give the name MATTER to an unextended active being? And, SECONDLY, Whether it be not ridiculously absurd to misapply names contrary to the common use of language?

HYL. Well then, let it not be called Matter, since you will have it so, but some THIRD NATURE distinct from Matter and Spirit. For what reason is there why you should call it Spirit? Does not the notion of spirit imply that it is thinking, as well as active and unextended?

PHIL. My reason is this: because I have a mind to have some notion of meaning in what I say: but I have no notion of any action distinct from volition, neither can I conceive volition to be anywhere but in a spirit: therefore, when I speak of an active being, I am obliged to mean a Spirit. Beside, what can be plainer than that a thing which hath no ideas in itself cannot impart them to me; and, if it hath ideas, surely it must be a Spirit. To make you comprehend the point still more clearly if it be possible, I assert as well as you that, since we are affected from without, we must allow Powers to be without, in a Being distinct from ourselves. So far we are agreed. But then we differ as to the kind of this powerful Being. I will have it to be Spirit, you Matter, or I know not what (I may add too, you know not what) Third Nature. Thus, I prove it to be Spirit. From the effects I see produced, I conclude there are actions; and, because actions, volitions; and, because there are volitions, there must be a WILL. Again, the things I perceive must have an existence, they or their archetypes, out of MY mind: but, being ideas, neither they nor their archetypes can exist otherwise than in an understanding; there is therefore an UNDERSTANDING. But will and understanding constitute in the strictest sense a mind or spirit. The powerful cause, therefore, of my ideas is in strict propriety of speech a SPIRIT.

HYL. And now I warrant you think you have made the point very clear, little suspecting that what you advance leads directly to a contradiction. Is it not an absurdity to imagine any imperfection in God?

PHIL. Without a doubt.

HYL. To suffer pain is an imperfection?

PHIL. It is.

HYL. Are we not sometimes affected with pain and uneasiness by some other Being?

PHIL. We are.

HYL. And have you not said that Being is a Spirit, and is not that Spirit God?

PHIL. I grant it.

HYL. But you have asserted that whatever ideas we perceive from without are in the mind which affects us. The ideas, therefore, of pain and uneasiness are in God; or, in other words, God suffers pain: that is to say, there is an imperfection in the Divine nature: which, you acknowledged, was absurd. So you are caught in a plain contradiction.

PHIL. That God knows or understands all things, and that He knows, among other things, what pain is, even every sort of painful sensation, and what it is for His creatures to suffer pain, I make no question. But, that God, though He knows and sometimes causes painful sensations in us, can Himself suffer pain, I positively deny. We, who are limited and dependent spirits, are liable to impressions of sense, the effects of an external Agent, which, being produced against our wills, are sometimes painful and uneasy. But God, whom no external being can affect, who perceives nothing by sense as we do; whose will is absolute and independent, causing all things, and liable to be thwarted or resisted by nothing: it is evident, such a Being as this can suffer nothing, nor be affected with any painful sensation, or indeed any sensation at all. We are chained to a body: that is to say, our perceptions are connected with corporeal motions. By the law of our nature, we are affected upon every alteration in the nervous parts of our sensible body; which sensible body, rightly considered, is nothing but a complexion of such qualities or ideas as have no existence distinct from being perceived by a mind. So that this connexion of sensations with corporeal motions means no more than a correspondence in the order of nature, between two sets of ideas, or things immediately perceivable. But God is a Pure Spirit, disengaged from all such sympathy, or natural ties. No corporeal motions are attended with the sensations of pain or pleasure in His mind. To know everything knowable, is certainly a perfection; but to endure, or suffer, or feel anything by sense, is an imperfection. The former, I say, agrees to God, but not the latter. God knows, or hath ideas; but His ideas are not conveyed to Him by sense, as ours are. Your not distinguishing, where there is so manifest a difference, makes you fancy you see an absurdity where there is none.

HYL. But, all this while you have not considered that the quantity of Matter has been demonstrated to be proportioned to the gravity of bodies. And what can withstand demonstration?

PHIL. Let me see how you demonstrate that point.

HYL. I lay it down for a principle, that the moments or quantities of motion in bodies are in a direct compounded reason of the velocities and quantities of Matter contained in them. Hence, where the velocities are equal, it follows the moments are directly as the quantity of Matter in each. But it is found by experience that all bodies (bating the small inequalities, arising from the resistance of the air) descend with an equal velocity; the motion therefore of descending bodies, and consequently their gravity, which is the cause or principle of that motion, is proportional to the quantity of Matter; which was to be demonstrated.