Book IV OF KNOWLEDGE AND OPINION
Chapter I: Of Knowledge in General
Section 1 "Our knowledge converdant about our ideas. Since the mind, in all its thoughts and reasonings, hath no other immediate object but its own ideas, which it alone does or can contemplate, it is evident that our knowledge is only conversant about them."
Section 2 "Knowledge is the perception of the agreement, or disagreement, of two ideas. Knowledge then seems to me to be nothing but the perception of the connexion and agreement, or disagreement and repugnancy, of any of our ideas. In this alone it consists. "
Chapter IV: Of the reality of knowledge
Section 3 "It is evident the mind knows no things immediately, but only by the intervention of the ideas it has of them. Our knowledge, therefore, is real only so far as there is a conformity between our ideas and the reality of things. But what shall be here the criterion? "
Chapter XI: Of Our Knowledge of the Existence of Other Things
Section 1: " Is to be had only by sensation. The knowledge of our own being we have by intuition. The existence of a God, reason clearly makes known to us, as has been shown. The knowledge of the existence of any other thing we can have only by sensation."
Section 3: "This, though not so certain as demonstration, yet may be called knowledge, and proves the existence of things without us. The notice we have by our senses of the existing of things without us, though it be not altogether so certain as our intuitive knowledge or the deduction of our reason employed about the clear abstract ideas of our own minds yet it is an assurance that deserves the name of knowledge. . . . But besides the assurance we have from our senses themselves, that they do not err in the information they give us of the existence of things without us when they are affected by them, we are further confirmed in this assurance by other concurrent reasons. "
Here are the reasons: turn them into arguments for the conclusion that our senses do not err.
Section 4 "First, because we cannot have them but by the inlets of the senses. First, it is plain those perceptions are produced in us by exterior causes affecting our senses because those that want the organs of any sense, never can have the ideas belonging to that sense produced in their minds. "
Turn this reason into an argument--- for example,
1. If our ideas are not caused by external qualities, then it must be possible for someone who lacks a particular sense organ to have ideas which belong to that organ.
2. But it is not possible for someone who lacks a particular sense organ to have ideas which belong to that organ.
So,
And now create similar arguments for these next three reasons:
Section 5 "Secondly, because an idea from actual sensation and another from memory are very distinct perceptions. Secondly, Because sometimes I find that I cannot avoid the having those ideas produced in my mind. "
Section 6 "Thirdly, pleasure or pain, which accompanies actual sensation, does not accompanyu the returning of those ideas without the external objects. Thirdly, Add to this, that many of those ideas are produced in us with pain, which afterwards we remember without the least offence. "
Section 7 "Fourthly, our sense assist one another's testimony of the existence fof outward things. Fourthly, Our senses in many cases bear witness to the truth of each other's report concerning the existence of sensible things without us."
And then Locke considers a possible objection from someone influenced by Descartes.
Section 8 "This certainty is as great as our condition needs. But yet, if after all this anyone will be so skeptical as to distrust his sense 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 thinks or our knowledge of anything, . . . "
What is Locke's response to this Cartesian objection?