Socratic Logic - Simple Apprehension

The following are the notes I have taken from Peter Kreeft's wonderful Socratic Logic textbook. I highly recommend you buy it. This is a book which deals with classical logic (as opposed to modern symbolic logic.) It is easily the best overall book on logic I have ever read and one of the few I have that are worth making notes from. I even have a small duotang with these notes in it I can carry around and reference on a regular basis.

Definition

Definitions help us to understand what a thing is.  The term comes from de-fino "to set limits around a thing."

Good definitions:

1. Remove ambiguity

2. Tell us a things essence

3. Should be clear and distinct

4. Are crucial to the Socratic method.  Socrates spent 80-90% of his time defining things.

Rules of Definition

A. Should not be too broad or too narrow.

B. Should be clear, not obscure.

C. Should be literal, not metaphorical.

D. Should be brief, not long.

E. Should be positive, not negative. (If possible)

F. Should not be circular.

Kinds of Definitions

A . Nominal

The definition of a word, not a thing defined by a word.

B. Real

1. Essential

Genus + Specific Difference

2. Non-Essential

a. By properties - predicable properties

b. By accidents - need lots of them

c. By causes

i. efficient cause - agent causation or 'genetic cause'

ii. final cause - purpose of thing

iii. material cause - contents, ie. water is H2O

iv. from effects - what thing does

Limits of Definition

The following things cannot be defined:

A. Infinite things

B. Individuals (only species)

C. Summa Genera (Highest genera, the Ten Categories)

D. Being itself

E. Transcendentals

1. something

2. one

3. true

4. good

5. beautiful