Husserl I. The Realm of Ideas

Philosophy 157

©2002, G. J. Mattey

Empiricism

• All substantive human knowledge is based on the input of the senses

• Reason by itself discovers only non-substantive connections between concepts

• Reason applied to sensory input yields generalizations which are only probable

Psychologism

• A form of empiricism• Adopted by John Stuart Mill, as well as a

number of German philosophers of the late nineteenth century

• Basic thesis: the “laws” of logic are only empirical generalizations based on observation of the workings of the human mind

Basic Argument for Psychologism

1. Inference from premises to conclusion is a psychological process.

2. Laws governing psychological processes are psychological laws.

3. Psychological laws are empirical generalizations.

4. So, laws governing inferences are empirical generalizations.

Kantian Response

• Psychological laws are descriptive, while laws of logic are normative

• Descriptive laws tell us what is, while normative laws tell us about what ought to be

• Analogy: basing moral laws on observation of human behavior alone

Rebuttal by Psychologism

• The purpose of logic is to further the goals of the mind

• How best to further these goals depends on how the mind works

• The workings of the mind are governed by psychological laws

Circularity Response

• Psychology itself depends on laws of logic

• If laws of logic are based on psychology, then they are based on themselves

• Laws of logic based on themselves are circular

Rebuttal by Psychologism

• Logic applies to itself, and so there is an apparent circularity: logic establishes the validity of the rules it presupposes

• But it does not do so by using laws of logic as premises in arguments establishing the validity of arguments

• Logic is used as a standard of valid arguments instead

The Middle Way

• Both sides have grasped part of the truth about the laws of logic

• Psychologism correctly recognizes that logic is used as a tool to regulate inference, which is a psychological process

• But it mistakenly takes this process to be the subject-matter of logic

• The real subject-matter of logic is an ideal realm

The Normativity of Logic

• A law of logic: no proposition is both true and false

• This law has no normative content: it says nothing about what one ought to believe

• But its meaning gives it an “intrinsic prerogative in the regulation of our thought”

The “Circularity” of Logic

• The proposition that no proposition is both true and false applies to itself

• It is not both true and false

• But this self-reference is not harmful, but “an obvious truism”

What Logic is About

• The laws of thought describe an ideal realm, just as with mathematics

• Populating the ideal realm are “Truth, Proposition, Subject, Object, Property, Ground and Consequent, Relation and Relatum, etc.”

• Truths regarding this realm are self-evident, involving a “primal givenness”

Phenomenology

• True and false judgments have the same phenomenological content

• The content of the judgment is what is “meant” by it

• There is a separate “experience of truth”• The truth is given in the agreement between

what is meant and what is present (the ideal objects, in the case of logic)

Logic and Evidence

• A judgment is true if and only if it is inwardly evident

• Being inwardly evident can be construed as a psychological state.

• But truth and inward evidence are only materially equivalent, and concern different subject-matters

• The law of non-contradiction governs what can be inwardly evident

• But the realm of the logically possible may outstrip the abilities of the human mind