The Problems of Philosophy - Chapter 7

(Originally Written September 21, 2005 in Book 2)

The Problems of Philosophy
Bertrand Russell
1912

Chapter 7 - On our Knowledge of General Principles

The inductive principle is necessary to all arguments based on experience; however, experience cannot prove or disprove it. The principle of induction is not alone in this characteristic.

The principle of inference is the means of drawing inferences based on a sensation. If this inference is then true, it is as true as the data itself.

An inference takes the pattern of stating:
If A is true then B is true
A is true
B is true

The principle is obvious and may seem trivial, but it is important because it is knowledge which is in "no way derived from objects of sense" (Russell, 72).

There are three laws of thought:
1) The law of identity - Whatever is, is
2) The law of contradiction - Nothing can bot be and not-be
3) The law of the excluded middle - Everything must be or not be

(3: This is only man's logic. God is not subject to this law) This was written in my margins, but to be honest I don't know what I meant by it

In addition to these principles (laws of thought and the principle of inference) which enables us to prove that from a given premise that something is certainly true, there are other logical principles that enable us to prove that there is greater or lesser probability that something is true. (These principles include the inductive principle)

All knowledge is elicited and caused by experience, however some knowledge is a priori. A priori is knowledge derived without reference to particular facts or experience.

"Nothing can be known to exist except by the help of experience" (Russell, 76). This means that if we want to prove something exists of which we have no experience of we must use premises (one or more) of things we have direct experience with.

The scope of a priori is strictly limited.

When anything is known by direct experience (immediately) it is known by experience alone. But, when anything is proved to exist without immediate experience both experience and a priori principles are required in the proof of that thing's existence.

Empirical knowledge rests wholly or partly on experience.

A priori knowledge is hypothetical and contends that things exist or may exist, but does not give actual existence.

"The most important example of non-logical a priori knowledge is knowledge as to ethical value" (Russell, 75-76).

Russell is not stating ethical value as what is useful or virtues because they do not need empirical premises; he is referring to "the intrinsic desirability of things" (Russell, 76).

"It is fairly obvious that they [judgments on the intrinsic value of something] cannot be proved by experience; for the fact that a thing exists or does not exist cannot prove either that it is good that it should exist or that it is bad" (Russell, 76).

Whether something's existence is good or bad falls into the scope of ethics.

The knowledge as to what is intrinsically of value is a priori in the same sense that logic is a priori; meaning that the truth of such knowledge cannot be proved or disproved by experience.

Pure mathematics is a priori.

Pg. 78-79 mortal men passage. If men are not mortal it would upset the entire fabric of our knowledge. What of Elijah who was taken into heaven? He was immortalized by God and yet the fabric of man's knowledge was not interrupted. Man's logic was superseded by God's presence.

Deduction takes us from general to general or from general to particular whereas induction takes us from particular to particular or particular to general.

All empirical generalizations are more uncertain than the instances of them.

A priori propositions include logic, pure mathematics and fundamental propositions of ethics.

The questions that arise from a priori are:

1. How is it possible that there should be such knowledge?
2. How can there be knowledge of general propositions in cases where we have not examined all the instances and never can (because they are infinite)?