of sound； which are conveyed by the ear； are really
different from each other； though； at the same time；
resembling。 Now if this be true of different colours； it
must be no less so of the different shades of the same
colour； and each shade produces a distinct idea； independent
of the rest。 For if this should be denied； it is possible；
by the continual gradation of shades； to run a colour
insensibly into what is most remote from it； and if you will
not allow any of the means to be different； you cannot；
without absurdity； deny the extremes to be the same。
Suppose； therefore； a person to have enjoyed his sight for
thirty years； and to have become perfectly acquainted with
colours of all kinds except one particular shade of blue；
for instance； which it never has been his fortune to meet
with。 Let all the different shades of that colour； except
that single one； be placed before him； descending gradually
from the deepest to the lightest； it is plain that he will
perceive a blank； where that shade is wanting； and will be
sensible that there is a greater distance in that place
between the contiguous colour than in any other。 Now I ask；
whether it be possible for him； from his own imagination； to
supply this deficiency； and raise up to himself the idea of
that particular shade； though it had never been conveyed to
him by his senses？ I believe there are few but will be of
opinion that he can： And this may serve as a proof that the
simple ideas are not always； in every instance； derived from
the correspondent impressions； though this instance is so
singular； that it is scarcely worth our observing； and does
not merit that for it alone we should alter our general
maxim。
Here； therefore； is a proposition； which not only
seems； in itself； simple and intelligible； but； if a proper
use were made of it； might render every dispute equally
intelligible； and banish all that jargon； which has so long
taken possession of metaphysical reasonings； and drawn
disgrace upon them。 All ideas； especially abstract ones； are
naturally faint and obscure： The mind has but a slender hold
of them： They are apt to be confounded with other resembling
ideas； and when we have often employed any term； though
without a distinct meaning； we are apt to imagine it has a
determinate idea annexed to it。 On the contrary； all
impressions； that is； all sensations； either outward or
inward； are strong and vivid： The limits between them are
more exactly determined： Nor is it easy to fall into any
error or mistake with regard to them。 When we entertain；
therefore； any suspicion that a philosophical term is
employed without any meaning or idea （as is but too
frequent）； we need but enquire； ？ And if it be impossible to
assign any； this will serve to confirm our suspicion。 By
bringing ideas into so clear a light we may reasonably hope
to remove all dispute； which may arise； concerning their
nature and reality。＇4＇
* * * *
SECTION III。
Of the Association of Ideas。
I/T is evident that there is a principle of connexion
between the different thoughts or ideas of the mind； and
that in their appearance to the memory or imagination； they
introduce each other with a certain degree of method and
regularity。 In our more serious thinking or discourse this
is so observable that any particular thought； which breaks
in upon the regular tract or chain of ideas； is immediately
remarked and rejected。 And even in our wildest and most
wandering reveries； nay in our very dreams； we shall find；
if we reflect； that the imagination ran not altogether at
adventures； but that there was still a connexion upheld
among the different ideas； which succeeded each other。 Were
the loosest and freest conversation to be transcribed； there
would immediately be observed something which connected it
in all its transitions。 Or where this is wanting； the person
who broke the thread of discourse might still inform you；
that there had secretly revolved in his mind a succession of
thought； which had gradually led him from the subject of
conversation。 Among different languages； even where we
cannot suspect the least connexion or communication； it is
found； that the words； expressive of ideas； the most
compounded； do yet nearly correspond to each other： A
certain proof that the simple ideas； comprehended in the
compound ones； were bound together by some universal
principle； which had an equal influence on all mankind。
Though it be too obvious to escape observation； that
different ideas are connected together； I do not find that
any philosopher has attempted to enumerate or class all the
principles of association； a subject； however； that seems
worthy of curiosity。 To me； there appear to be only three
principles of connexion among ideas； namely； ；
in time or place； and or 。
That these principles serve to connect ideas will not；
I believe； be much doubted。 A picture naturally leads our
thoughts to the original：＇5＇ the mention of one apartment in
a building naturally introduces an enquiry or discourse
concerning the others：＇6＇ and if we think of a wound； we can
scarcely forbear reflecting on the pain which follows it。＇7＇
But that this enumeration is complete； and that there are no
other principles of association except these； may be
difficult to prove to the satisfaction of the reader； or
even to a man's own satisfaction。 All we can do； in such
cases； is to run over several instances； and examine
carefully the principle which binds the different thoughts
to each other； never stopping till we render the principle
as general as possible。＇8＇ The more instances we examine；
and the more care we employ； the more assurance shall we
acquire； that the enumeration； which we form from the whole；
is complete and entire。＇9＇
Instead of entering into a detail of this kind； which
would lead us into many useless subtilties； we shall
consider some of the effects of this connection upon the
passions and imagination； where we may open up a field of
speculation more entertaining； and perhaps more instructive；
than the other。
As man is a reasonable being and is continually in
pursuit of happiness； which he hopes to find in the
gratification of some passion or affection； he seldom acts
or speaks or things without a purpose and intention。 He has
still some object in vies； and however improper the means
may sometimes be which he chooses for the attainment of his
end； he never loses view of an end； nor will he so much as
throw away his thoughts or reflections where he hopes not to
reap any satisfaction from them。
In all compositions of genius； therefore； it is requisite that the
writer have some plan or object； and though he may be hurried
from this plan by the vehemence of thought； as in an ode；
or drop it carelessly； as in an epistle or essay； there must
appear some aim or intention in his first setting out； if not in the
composition of the whole work。 A production without a design
would resemble more the ravings of a madman than the sober
efforts of genius and learning。
As this rule admits of no exception； it follows that in
narrative compositions the events or actions which the
writer relates must be connected together by some bond or
tie： They must be related to each other in the imagination；
and form a kind of which may bring them under one
plan or view； and which may be the object or end of the
writer in his first undertaking。
This connecting principle among the several events
which form the subject of a poem or history may be very
different according to the different designs of the poet or
historian。 O/VID has formed his plan upon the connecting
principles of resemblance。 Every fabulous transformation
produced by the miraculous power of the gods falls within
the compass of his work。 There needs but this one
circumstance； in any event； to bring it under his original
plan or intention。
An annalist or historian who should undertake to write
the history or Europe during any century would be influenced
by the connection of contiguity in time or place。 All events
which happen in that portion of space and period of time are
comprehended in his design； though in other respects
different and unconnected。 They have still a species of
unity amidst all their diversity。
But the most usual species of connections among the
different events which enter into any narrative composition
is that of cause and effect； while the historian traces the
series of actions according to their natural order； remounts
to their secret springs and principles； and delineates their
most remote consequences。 He chooses for his subject a
certain portion of that great chain of events which compose
the history of mankind： Each link in this chain he
endeavours to touch in his narration； sometimes unavoidable
ignorance renders all his attempts fruitless； sometimes he
supplies by conjecture what is wanting in knowledge； and
always he is sensible that the more unbroken the chain is
which he presents to his readers； the more perfect is his
production。 He sees that the knowledge of causes is not only
the most satisfactory； this relation or connection being the
strongest of all others； but also the most instructive；
since it is by this knowledge alone we are enabled to
control events and govern futurity。
Here； therefore； we may attain some notion of that
of about which all critics after Aristotle
have talked so much； perhaps to little purpose； which they
directed not their taste or sentiment by the accuracy of
philosophy。 It appears that in all productions； as well as
in the epic and tragic； there is a certain unity required；
and that on no occasion our thoughts can be allowed to run
at adventures if we would produce a work that will give any
lasting entertainment to mankind。 It appears； also； that
even a biographer who should write the life of Achilles
would connect the events by showing their mutu