Chapter I

THE LOWER FORMS OF ABSTRACTION.—ABSTRACTION PRIOR TO SPEECH.

Two forms of intellectual activity: association and
dissociation.—Abstraction belongs to the second type. Its
positive and negative conditions. It is a case of attention:
psychical reinforcement.—It is in embryo in concrete
operations: in perception, and the image. Its practical
character.—Generalisation belongs to the first type. Problem of
the _primum cognitum_; difference or resemblance?—Hierarchy of
general ideas: need of a notation. Three great classes.—Lower
forms of abstraction and generalisation or pre-linguistic
period, characterised by absence of words 1

ANIMALS.

Different observations. Numeration in animals; what does it
consist of?—Mode of formation and characteristics of generic
images. Reasoning in animals.—Reasoning from particular to
particular: how this differs from simple association.—Reasoning
by analogy.—The logic of images: its two degrees; its
characteristics. Does not admit of substitution; always has a
practical aim.—Discussion of certain cases 11

CHILDREN.

Does intelligence start from the general or the particular?
A badly-stated question. Intelligence proceeds from the
indefinite to the definite.—Characteristics of generic
images in children; examples.—Numeration; its narrow limits.
Difference between real numeration and perception of a
plurality 31

DEAF-MUTES.

These furnish the upper limit of the logic of images.—Their
natural language. Vocabulary. All their signs are abstractions.
Syntax of position; disposition of terms according to order of
importance.—Intellectual level 39

ANALYTICAL GESTURES.

General classification of signs.—Gesture, an intellectual,
not an emotional, instrument; its wide distribution. Syntax
identical with that of deaf-mutes.—Comparison between phonetic
language and language of analytical gesture.—Reason why speech
has prevailed 48

CHAPTER II.

SPEECH.

Language in animals.—The origin of speech; principal
contemporaneous hypotheses; instinct, progressive evolution.
The cry, vocalisation, articulation. Transitional forms:
co-existence of speech and of the language of action;
co-existence of speech and of inarticulate sounds.—The
development of speech. Protoplasmic period without
grammatical functions.—Roots; two theories: reality, and
residue of analysis.—Did speech begin with words or with
phrases?—Successive appearance of parts of speech. Adjectives
or denominations of qualities. The substantive a contraction
of the adjective. Verbs not a primitive phenomenon; the
three degrees of abstraction.—Terms expressive of relations.
Psychological nature of relation, may be reduced to change or
movement. Function of analogy 54

CHAPTER III.

INTERMEDIATE FORMS OF ABSTRACTION.

Division into two classes according to the function of the
word.—First class. Words not indispensable, and only in a
limited degree the instrument of substitution.—Difference
between generic images and lower concepts. Characteristics of
these two classes. Is there continuity between the two? Nature
of the lower forms of intermediate abstraction, according to
languages, numeration, etc. Concrete-abstract period.—Second
class. Words are indispensable and become an instrument of
substitution.—Difficulty in finding examples.—History of
zoölogical classification: pre-scientific period: Aristotle,
Linnæus, Cuvier, etc., contemporary writers. Progress towards
unity 86

CHAPTER IV.

HIGHER FORMS OF ABSTRACTION. THEIR NATURE.

Object of the chapter: What is there in consciousness, when we
think by concepts?—The general idea as a psychical state may be
reduced to varieties. Investigation of this point: the method
pursued.—Reduction to three principal types. Concrete type the
most widely distributed. Variation; reply by association of
ideas. Visual typographic type: printed words seen and nothing
further.—Auditory type; less common.—Interrogations by general
propositions: same results. Investigation of cases in which
words exist alone in consciousness. Is it possible to think
with words only? Rôle of unconscious knowledge. General ideas
are intellectual habits.—Natural antagonism between the image
and the concept. Its causes.—Are there general ideas or merely
general terms? 111