PHL220. Quine and Ullian, C5 and C6
Quine and Ullian, C5 and C6
Chapter 5: Testimony
- Claim: there are two primary uses to language. Getting
knowledge from others, and getting others to do what we want
them to do.
- Testimony is like a microscope: it extends the range
of observation sentences we can come to know. We learn from
others what observation sentence they have confirmed by their
- We begin with the assumption that testimony is true,
and often reinterpret utterances to make them true. We conclude
someone is lying only after that is the simplest interpretation
of significant evidence to that effect.
- Testimony is more reliable when multiply confirmed -- but
the sources of the testimony must be independent!
- Common "knowledge" is an unreliable source of testimony.
- Claim: we cannot believe a claim that we know is impossible.
- Claim: we cannot will to believe something and believe it
on those grounds alone.
- We do believe things on faith, of course. For example,
faith in claims we cannot ourselves confirm of scientists.
Chapter 6: Hypotheses
- Although some rationalists have believed we could
establish all truths working from self-evident truths; and
some empiricists believed we could establish all truths
working from self-evident truths and basic given experiences;
we know that only the most basic logic can be constructed from
self-evident truths. Natural science thus requires something
- We need to identify the virtues of hypotheses (Note:
Q & U's virtues of hypotheses roughly correspond to what we earlier
called the criteria for evaluating and comparing theories.)
- Conservatism: coherence with prior beliefs.
- Modesty: the hypothesis entails less than the alternative
- Simplicity: simpler hypotheses are better.
- Generality: wider range of application is better.
- Refutability: this is falsifiability.
- A note about simplicity: Quine contends that simplicity
is subjective. Many of us do not believe that. For example,
a measure called Kolmogorov complexity is objective: it says
that one string or equation or any other statement A is
simpler than another B if the smallest computer program that
can generate that string A is smaller than the smallest
computer program that can generate B.