Hume on Force and Vivacity
and the Content of Ideas
David Banach
Department of Philosophy
St. Anselm College
The everlasting universe of things
Flows through the mind, and rolls in rapid waves,
Now dark -- now glittering -- now reflecting gloom -Now lending splendour, where from secret springs
The source of human thought its tributes brings
P. B. Shelley, Mont Blanc
The Theory of Ideas
Concepts or Ideas are mental
representations entertained in the mind.
 Thought involves the causal relations of
these ideas.
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Pragmatic or Conceptual Role Theories
Concepts do not directly have
representational content in themselves but
only in the context of a judgment,
proposition, or conceptual scheme.
 Ideas get their meaning in the context of
a system of dispositions to classify and act
with respect to objects.
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Ideas
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Ideas are copies of impressions.
They differ only in force and vivacity, not in
content.
Impressions transmit their force and vivacity
(what I call their impetus) to ideas.
Quote 2: Impressions and ideas differ not in
content but only in impetus
“The first circumstance, that strikes my eye, is
the great resemblance betwixt our impressions
and ideas in every other particular, except their
degree of force and vivacity. “
Belief
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Belief is a habit associated with an idea.
This habit is manifested in the force and
vivacity with which the idea is held.
Quote 3: Belief an impetus
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Thus it appears, that the belief or assent, which
always attends the memory and senses, is
nothing but the vivacity of those perceptions they
present; and that this alone distinguishes them
from the imagination. To believe is in this case to
feel an immediate impression of the senses, or a
repetition of that impression in the memory. 'Tis
merely the force and liveliness of the perception,
which constitutes the first act of the judgment,
and lays the foundation of that reasoning, which
we build upon it, when we trace the relation of
cause and effect.
Quote 6: Impetus does not change content. Belief an
impetus
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All the perceptions of the mind are of two kinds, viz.
impressions and ideas, which differ from each other only in
their different degrees of force and vivacity.' Our ideas are
copy'd from our impressions, and represent them in all
their parts. When you would any way vary the idea of a
particular object, you can only increase or diminish its force
and vivacity. If you make any other change on it, it
represents a different object or impression. The case is the
same as in colours. A particular shade of any colour may
acquire a new degree of liveliness or brightness without any
other variation. But when you produce any other variation,
'tis no longer the same shade or colour. So that as belief
does nothing but vary the manner, in which we conceive
any object, it can only bestow on our ideas an additional
force and vivacity. An opinion, therefore, or belief may be
most, accurately defined, A LIVELY IDEA RELATED TO OR
ASSOCIATED WITH A PRESENT IMPRESSION.
Thought the transmission of impetus.
Impressions and ideas convey their
impetus according to three basic laws of
(human) nature.
 1. Resemblance
 2. Contiguity
 3. Cause and Effect
 Thought is merely the flow of this force
and vivacity as it is carried along the
succession of ideas.
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Quote 7: Impetus something felt but mysterious.
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An idea assented to feels different from a fictitious idea,
that the fancy alone presents to us: And this different
feeling I endeavour to explain by calling it a superior force,
or vivacity, or solidity, or firmness, or steadiness. This
variety of terms, which may seem so unphilosophical, is
intended only to express that act of the mind, which
renders realities more present to us than fictions, causes
them to weigh more in the thought, and gives them a
superior influence on the passions and imagination.
... I confess, that 'tis impossible to explain perfectly this
feeling or manner of conception. We may make use of
words, that express something near it. But its true and
proper name is belief, which is a term that every one
sufficiently understands in common life. .
Abstract Ideas
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All ideas are particular and determinate.
Ideas became general by bringing to mind
an indefinite number of other ideas
according to a custom of habit associated
with the word or idea.
Quote 4:
Meaning of general idea a custom
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A particular idea becomes general by being annex'd to a
general term; that is, to a term, which from a customary
conjunction has a relation to many other particular ideas,
and readily recalls them in the imagination.
The only difficulty, that can remain on this subject,
must be with regard to that custom, which so readily
recalls every particular idea, for which we may have
occasion, and is excited by any word or sound, to which we
commonly annex it. The most proper method, in my
opinion, of giving a satisfactory explication of this act of
the mind, is by producing other instances, which are
analogous to it, and other principles, which facilitate its
operation. To explain the ultimate causes of our mental
actions is impossible. 'Tis sufficient, if we can give any
satisfactory account of them from experience and analogy.
Hume on Distinctions of Reason
We have no abstract idea of
shape without color.
One single colored, shaped idea
leads us, according to custom,
to other ideas that resemble it
with respect to shape, but not
color.
Distinctions of Reason
Nor do we have an idea of color
without shape.
In this case, the very same single
colored idea of the sphere leads
us, according to a different
custom to other ideas that
resemble it with respect to color
but not shape.
The power of the impetus associated
with abstract ideas
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a. Ideas of large numbers, such as 1000, do
not have a clear and determinate image.
b. An entire verse of poetry, though we can't
recall it at the moment, can be brought back to
us in a moment by one word.
c. We have no clear image for our complex
ideas, such as church, negotiation, or conquest.
d. Knowing an idea bestows a marvelous
ability to bring up relevant ideas at appropriate
times without having a clear idea how we do so.
Quote 5:
Custom or impetus a mysterious power of the soul
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The fancy runs from one end of the universe to
the other in collecting those ideas, which belong
to any subject. One would think the whole
intellectual world of ideas was at once subjected
to our view, and that we did nothing but pick out
such as were most proper for our purpose. There
may not, however, be any present, beside those
very ideas, that are thus collected by a kind of
magical faculty in the soul, which, tho' it be
always most perfect in the greatest geniuses, and
is properly what we call a genius, is however
inexplicable by the utmost efforts of human
understanding.
Summary
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1. Apart from the representational content of an idea there
is another component: its force and vivacity, its
impetus.
2. The impetus of ideas is felt, part of the phenomenology
of the idea, though it is distinct from the content of the idea
and is not itself another idea. (Indeed, it would have been
more consistent for Hume to consider emotions and
sentiments as these types of impetüs than as separate
ideas.)
3. The impetus of ideas, as the name suggests, is active, is
connected with habit or custom, and directs the production
and flow of ideas.
4. The meaning of general ideas is a custom, the unrepresented meaning of an idea is its impetus, which
is distinct from its definition, or list of instances, or explicit
rules for producing these instances.
The content of ideas are in the habits that connect
them, not their intentional content itself.
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Once one sees the way ideas actually do
their work for Hume, it becomes clear that
they are merely tokens, along for the ride
in the real business of the transmission of
the force or impetus that thought involves.
A consideration of Hume’s view of abstract
ideas suggests that the real content of
thought lies within the impetus, not the
idea.
Connectionism and the flow of information
Neural Networks in a Laminar Cortex
Figure from Paul Churchland, A Neurocomputational Perspective, 1989
Quote 8:
Impetus transmitted from idea to idea, originates in object.
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I would willingly establish it as a general maxim in the
science of human nature, that when any impression
becomes present to us, it not only transports the mind to
such ideas as are related to it, but likewise communicates
to them a share of its force and vivacity.
Now 'tis evident the continuance of the disposition depends
entirely on the objects, about which the mind is employ'd;
and that any new object naturally gives a new direction to
the spirits, and changes the disposition; as on the contrary,
when the mind fixes constantly on the same object, or
passes easily and insensibly along related objects, the
disposition has a much longer duration
The Impetus of Ideas.
1.
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Arises from the object.
Is active
Is felt.
Is formal.
It is felt as the form of our impressions of
objects as they inform our habits of
connection.
The Flow of Ideas
The secret strength of things
 Which governs thought, and to the infinite
dome
 Of heaven is as a law, inhabits thee!
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