things must be possible, that is, nothing inconsistent must be included in their definition.  I say, secondly, that, although we believe things to exist which we do not perceive, yet we may not believe that any particular thing exists, without some reason for such belief:  but I have no reason for believing the existence of Matter.  I have no immediate intuition thereof:  neither can I immediately from my sensations, ideas, notions, actions, or passions, infer an unthinking, unperceiving, inactive Substance—­either by probable deduction, or necessary consequence.  Whereas the being of my Self, that is, my own soul, mind, or thinking principle, I evidently know by reflexion.  You will forgive me if I repeat the same things in answer to the same objections.  In the very notion or definition of material substance, there is included a manifest repugnance and inconsistency.  But this cannot be said of the notion of Spirit.  That ideas should exist in what doth not perceive, or be produced by what doth not act, is repugnant.  But, it is no repugnancy to say that a perceiving thing should be the subject of ideas, or an active thing the cause of them.  It is granted we have neither an immediate evidence nor a demonstrative knowledge of the existence of other finite spirits; but it will not thence follow that such spirits are on a foot with material substances:  if to suppose the one be inconsistent, and it be not inconsistent to suppose the other; if the one can be inferred by no argument, and there is a probability for the other; if we see signs and effects indicating distinct finite agents like ourselves, and see no sign or symptom whatever that leads to a rational belief of Matter.  I say, lastly, that I have a notion of Spirit, though I have not, strictly speaking, an idea of it.  I do not perceive it as an idea, or by means of an idea, but know it by reflexion.

HYL.  Notwithstanding all you have said, to me it seems that, according to your own way of thinking, and in consequence of your own principles, it should follow that you are only a system of floating ideas, without any substance to support them.  Words are not to be used without a meaning.  And, as there is no more meaning in spiritual substance than in material substance, the one is to be exploded as well as the other.

Phil.  How often must I repeat, that I know or am conscious of my own being; and that I myself am not my ideas, but somewhat else, a thinking, active principle that perceives, knows, wifls, and operates about ideas.  I know that I, one and the same self, perceive both colours and sounds:  that a colour cannot perceive a sound, nor a sound a colour:  that I am therefore one individual principle, distinct from colour and sound; and, for the same reason, from aft other sensible things and inert ideas.  But, I am not in like manner conscious either of the existence or essence of Matter.