INTRODUCTION 1087
Although...comprehensive construction is part of the business of philosophy, I do
not believe it is the most important part. The most important part, to my mind, con-
sists in criticizing and clarifying notions which are apt to be regarded as fundamental
and accepted uncritically. As instances I might mention: mind, matter, consciousness,
knowledge, experience, causality, will, time. I believe all these notions to be inexact
and approximate, essentially infected with vagueness, incapable of forming part of
any exact science.Second, in “criticizing and clarifying notions,” Russell was committed to the
principle of parsimony known as “Ockham’s Razor” (after the medieval thinker,
William of Ockham, see p. 358). Ockham’s injunction asserted that “entities are
not to be multiplied beyond necessity,” meaning one should always seek the sim-
plest explanation. Russell’s version of this principle, articulated in several of his
works, states that “Whenever possible, substitute constructions out of known enti-
ties for inferences to unknown entities.”
In the selection from The Problems of Philosophyreprinted here, Russell
wields this razor in an analysis of the common objects of our sensory perception
and our language about such objects. Russell points out that sense-data are the
only “known entities” actually given in experience:
What the senses immediatelytell us is not the truth about the object as it is apart
from us, but only the truth about certain sense-data which, so far as we can see,
depend upon the relations between us and the object. (Emphasis in original.)Rather than inferring some “unknown entity” (such as “being” or “substance”)
as the cause of our sense-data, we can consider a given object to be the class or
collection of all sense-data we normally associate with that object. Our knowledge
of physical objects is not direct but is gained by “acquaintance” with the sense-
data that make up the appearance of an object.
The language used to make propositions about such objects also depends on
acquaintance. To use language in a meaningful manner, “the meaning we attach to
our words must be something with which we are acquainted” either in terms of a
thing or a description. Using Russell’s example, a statement about Julius Caesar
can be meaningful even though we have no acquaintance with the “thing” (i.e., we
have not met Caesar) because we do have in mind some description of Caesar.
Although this selection includes some of Russell’s major themes and gives
some sense of his style, his contributions to philosophy go beyond what has been
included. His work in mathematics and logic changed both of those disciplines;
his theory of logical atomism represented an important step in the philosophy of
language; his theories of descriptions and of types helped clear up a number of
logical puzzles; and in addition there are his writings on education, sociology,
politics, and religion. In short, Russell touched on virtually all areas of human
existence, and even those who differ with his conclusions cannot help but be
impressed with the breadth and depth of his thought.
For biographical information, see Ronald William Clark,The Life of Bertrand
Russell(New York: Knopf, 1976); Katharine Tait,My Father, Bertrand Russell
(Bristol, UK: Thoemmes, 1996); or Russell’s autobiography,The Autobiography
of Bertrand Russell(Boston: Little, Brown, 1967). A.J. Ayer,Russell and Moore: