Philosophy 101 (Bentley College)

Assignment for Monday, October 18

Reading:

"Notes on Logic, part II" (PDF file; to be handed out in class on 10/13)
A. J. Ayer, "Knowing as Having the Right to Be Sure"

Notes and questions:

I have made the text by Ayer available in web-page form for your convenience. However, because the pagination of web pages varies from one printout to another, you must use paragraph numbers, not page numbers, in citing this text. (In writing, use the abbreviation "par." or "parag." or the symbol "¶" to indicate paragraph numbers) This will be the case for all future readings that are presented in web-page form.
The main point of this set of notes on logic is to explain the distinction between valid and invalid arguments (§§ 1–7). You should be able both to define the terms and to apply the distinction. You need to understand the tems in order to understand what Ayer says in ¶¶ 1 and 2 of his piece.
You will also need to understand what necessary and sufficient conditions are (see § 16 of the notes and ¶ 7 of Ayer). Ayer's piece is an attempt to identify the necessary and sufficient conditions for knowing something to be the case.
Finally, you should learn from the notes how to recognize at least some valid argument forms. At a minimum, you should be able to recognize instances of modus ponens (or affirming the antecedent; § 8) and modus tollens (or denying the consequent; § 9), and you should be able to distinguish these from their counterfeits, affirming the consequent (§ 13) and denying the antecedent (§ 14).
In ¶ 1, Ayer makes the claim that "it is possible to be completely sure of something which is in fact true, but yet not to know it." The claim is crucial to the argument of the piece, because the remainder is concerned with determining wherein the difference between knowing something to be so and merely being sure of something which in fact is so consists. What basis does Ayer provide for his claim? How can it happen that someone is sure of something which is in fact true yet not know it?
Paragraphs 2 and 3 may be rather hard to follow, so I will just tell you what is going on here. Ayer is considering the suggestion that the way that we can differentiate between knowledge and mere correct belief is by considering how, in a case of knowledge, the question "How do you know?" may satisfactorily be answered. The idea here is that what makes the difference between knowledge and mere correct belief is the possession of sufficiently strong backing. But Ayer argues, first, that it hardly seems possible to say in general what counts as sufficiently strong backing (¶ 2), and second, that there seem to be many cases of in which someone knows something but cannot provide any satisfactory answer to the question "How do you know?" (¶ 3).
Ayer allows that there may be no difference between the state of mind of the person who knows something to be so but cannot say how he knows and that of the person who does not know but merely believes correctly that something is so (¶ 4). Wherein, then, does the difference consist, according to Ayer?