philosophy

Philosophy 101, Summer Semester 2021

Handout #2

A. J. Ayer, Knowing as Having the Right to be Sure

· What is known should be true

· But this is not sufficient, not even if one adds that one must be sure of what one knows

· It is possible to be sure of something which is true, yet not to know it

· Consider case of man walking under ladder

· What is missing?

· He arrived at his conclusion by an unreliable process

· But what are the standards of reliability here?

· Question to ask: how do you know?

· Perception, testimony, memory all provide answers

· But whether they are good ones depends on the circumstances

· It’s not practical to draw up a general list of the conditions under which perception, testimony, and memory are reliable

· Moreover, one may know that P without being able to say how one knows it

· Consider someone who is amazingly reliable at predicting lottery results

· What, then, becomes of the distinction between knowledge and true belief?

· From the perspective of the person who knows, there may be no difference

· To say he knows is simply to concede him the right to be sure

· Where we draw the line is a matter of practical convenience

· In conclusion, these are the necessary and sufficient conditions for knowing that something is the case:

1. What one is said to know has to be true

2. One has to be sure of it

3. One has to have the right to be sure

· Many of the questions philosophers raise about the nature of knowledge thus turn out to be questions about the legitimacy to call something ‘knowledge’