General Ideas are formed by the coincident imprint of several objects
in some respects different, but which have all a resemblance as
objects, and are besides the signs of the same sentimental effect.
If the effects are different the confusion of the objects occasions
practical error, as when we mistake one man for another whom he
closely resembles. Though the sentimental utilities should be the
same, the object cannot be reduced to a common idea if they are quite
dissimilar: for example, a sand-glass and a watch have similar uses,
but they cannot be generalized. The value of generalisation to a
thinker is that it economises memory and recollection by making one
common or average idea do duty for many particular ideas. Let us
follow the process in detail.
The first perception of an object leaves an imprint in the substance
of the intellect. A second perception partially resembling the first
revives the first to the extent at least of the resemblance. Supposing
this is done by a hundred similar objects it is plain that the
resembling properties will have been experienced a hundred times,
whereas the distinguishing attributes may have been felt a few times
only, in some cases only once. Unless we have special reasons for
observing the differences and so deepening the impressions of them,
they will fade from our memory at a rate corresponding to the paucity
of experiences. The most general idea will last longest because
_there_ the impression has been very deep. Our idea of Man or Animal
will on this principle, as it is found to do in fact, outlast our
memory of many concrete men and animals.
The objects that contribute to form a general idea or Class are
commonly said to 'belong to,' or to 'inhere in,' or to be 'brought
under' the idea or class. All these metaphors are wrong and occasion
mistakes. Generalisation is nothing but condensed or epitomised
recollection; it is practised by ourselves for our own convenience,
and does not imply any essential or extra-personal relation between
the objects. We are free to classify things in any order we find
useful. A farmer's classification of some animals into cattle, game,
fowls, birds, and vermin, is perfectly legitimate, for each species is
based on a different utility for him.
We should distinguish general ideas which we ourselves have drawn from
our primary experience, from the ideas suggested by verbal definitions
of general ideas formed by other minds. Supposing the objects in
question to be quite unknown to us, the definitional idea is more like
a particular or imaginary idea than a general idea. It is a single
thin rigid idea, utterly unlike the flexible suggestive thought
evolved from a large mass of personal experience. Definitional general
ideas are as unsatisfactory as described objects, but we are sometimes
compelled to use both when personal experience is totally wanting.
It is a common error to suppose that general ideas cannot exist in the
intellect without words by which to name them. Words and other modes
of marking ideas are useful in all departments of thought, but
not more necessary in general thought than in any other. An active
intellect makes thousands of observations and scores of general ideas
which it may have no means or wish to express in language.
Generalisation is very like the operation called composite
photography. A number of persons are posed in the same attitude and
partially photographed on the same plate. The result is an average
or mean likeness of the whole group, but not an exact portrait of
any individual. So general ideas are 'means' or 'averages' of many
resembling but slightly differing objects.
There are other things in the photographic art remarkably similar to
intellectual thinking. The gelatine film behaves very like the mental
plasma: only one other physical object (so far as I am aware) is a
better image of the plasm.
In theory the object or phenomenon has no importance. Even when it
has the quality we call 'beauty,' that is not a property of the
bare object, for it is not seen by every person or animal with good
eyesight; it is a sentimental effect associated with the object. Hence
we might, if it were possible, ignore all objects except those which
have value to us as signs of sentimental effects.
But in practice we cannot do this. Objects are thrust upon our notice
which we cannot avoid, and which have no sentimental interest for us.
These objects are necessarily classified according to their phenomenal
appearance only, and such ideas lack an essential characteristic of
true general ideas. But we cannot prevent their formation in the
mind, for generalisation is merely a kind of abbreviated memory, and,
objects being once perceived, their recollection is to a great extent
beyond our control.
Artificial and adventitious utilities produce the same kind of
one-sided generalisation. If society pays a man in fame or money to
observe and describe certain things, his classification of them will
be purely phenomenal. He will classify dogs with wolves and nightshade
with potato, and will lump together the whole population of a country
in one class, although it consists of the most divers elements--fools
and philosophers, rogues and righteous, saints and sinners, patricians
and plebeians. These are differences much more important than sameness
of nationality, colour, race, or language.
This practice, no doubt, gives symmetrical classifications. The
greater classes are subdivided into subordinate classes, and these
again into lower classes in a many-stepped series. Gradation occurs
also in true generalisation, but not to the same extent.
If we confine our observation to things that are much like each other,
the average idea will not be greatly different from a particular idea:
this is called _lowness_ in generality. If we run together quadrupeds,
bipeds and fishes, we shall have a much higher general idea: the
average will be very unlike any concrete animal. The higher we
generalise the smaller becomes the content of the idea, but the wider
its extension, that is, the realm of objects from which it has been
drawn, or which it is considered to represent. The usual practice is
to generalise by fine gradations. Get the general idea of sheep, then
of cow, then of horse; then average the averages. The result is much
the same if we run all the objects together and average them in
one operation, but the slower process gives the neater results. The
gradations of generality are distinguished by names such as (beginning
from below) variety, species, genus, class, family, kingdom.
'Conceptualism' is the metaphysical doctrine now prevalent with
respect to general ideas. They are regarded not as objects nor as
essences, but as forms of consciousness depending more or less on
our own mental activity. This is true enough so far as it goes, but
without a substantial plasm to hold the 'concept' its formation and
endurance are quite inexplicable.