Thus I see, whilst I write this, I can change the appearance of the paper; and by designing the letters, tell beforehand what new idea it shall exhibit the very next moment, by barely drawing my pen over it:  which will neither appear (let me fancy as much as I will) if my hands stand still; or though I move my pen, if my eyes be shut:  nor, when those characters are once made on the paper, can I choose afterwards but see them as they are; that is, have the ideas of such letters as I have made.  Whence it is manifest, that they are not barely the sport and play of my own imagination, when I find that the characters that were made at the pleasure of my own thoughts, do not obey them; nor yet cease to be, whenever I shall fancy it, but continue to affect my senses constantly and regularly, according to the figures I made them.  To which if we will add, that the sight of those shall from another man, draw such sounds as I beforehand design they shall stand for, there will be little reason left to doubt that those words I write do really exist without me, when they cause a long series of regular sounds to affect my ears, which could not be the effect of my imagination, nor could my memory retain them in that order.

8.  This Certainty is as great as our Condition needs.

But yet, if after all this any one will be so sceptical as to distrust his senses, and to affirm that all we see and hear, feel and taste, think and do, during our whole being, is but the series and deluding appearances of a long dream, whereof there is no reality; and therefore will question the existence of all things, or our knowledge of anything:  I must desire him to consider, that, if all be a dream, then he doth but dream that he makes the question, and so it is not much matter that a waking man should answer him.  But yet, if he pleases, he may dream that I make him this answer, That the certainty of things existing in rerum natura when we have the testimony of our senses for it is not only as great as our frame can attain to, but as our condition needs.  For, our faculties being suited not to the full extent of being, nor to a perfect, clear, comprehensive knowledge of things free from all doubt and scruple; but to the preservation of us, in whom they are; and accommodated to the use of life:  they serve to our purpose well enough, if they will but give us certain notice of those things, which are convenient or inconvenient to us.  For he that sees a candle burning, and hath experimented the force of its flame by putting his finger in it, will little doubt that this is something existing without him, which does him harm, and puts him to great pain:  which is assurance enough, when no man requires greater certainty to govern his actions by than what is as certain as his actions themselves.  And if our dreamer pleases to try whether the glowing heat of a glass furnace be barely a wandering imagination in a drowsy man’s fancy, by putting his hand