Contemporaries who thought that
Berkeley was “half right”
Leibniz:
right: the only ultimately real thing is
minds (monads) and their
“perceptions”
right: there is no such thing as absolute
space or time
wrong: matter does not exist
(matter is the way spirits appear to
one another, and so is founded
on the constitution of spirits,
though it is not independently
real)
wrong: God imposes ideas on us in
accord with established laws
(there is instead a pre-established
harmony)
wrong: the only ideas are images
(there are also abstract ideas)
wrong: extension is only finitely divisible
(it is the paradoxes associated with
the infinite divisibility of extension
that prove that it must be
phenomenal)
Contemporaries who thought that
Berkeley was “half right,” cont.d
Johnson:
right: there is no material world; sensible
things are just collections of ideas
right: we have an intellectual grasp of
our minds
wrong: we have no abstract notions
Contemporaries who thought that
Berkeley was “half right,” cont.d
Hume:
right: there are no abstract ideas
right: there is no knowledge of bodies
existing in an external world
right: space and time are not infinitely
divisible
wrong: an idea cannot exist apart from
being perceived by some mind
(each simple idea is different from
everything else in existence, and
hence distinguishable and
separable from everything else)
wrong: minds are perceiving, active
things distinct from their ideas, which
are perceived and inert
Contemporaries who thought that
Berkeley was “half right,” cont.d
Reid:
right: we do not immediately perceive
distance outwards or objective
magnitude
wrong: we do not immediately perceive
orientation, situation, or number
right: nothing can be like an idea
(mental state) but another idea
(mental state)
wrong: to conceive an object is to
perceive a mental image of that
object
Hume’s Arguments to Confirm
Berkeley’s Account of Abstract Ideas
(“one of the greatest and most valuable discoveries that
has been made of late years in the republic of letters”)
A preliminary observation:
We do not consider objects to be of different kinds or
sorts on account of every small alteration in
quantity (e.g., size, shape) or quality (e.g., colour)
Consequently, the idea of a kind must be either:
 an idea that “abstracts” from every particular
degree of quantity and quality and represents an
object that has none of these particular degrees
(e.g., a line of no particular length or colour)
 a “general” idea that includes every possible
different degree of quantity and quality (e.g., an
idea of all the different possible lines)
Hume’s Arguments to Confirm
Berkeley’s Account of Abstract Ideas,
cont.’d
Hume’s first argument against abstract
ideas:
different=distinguishable=separable
But the precise length of a line is not different or
distinguishable from the line itself.
or the precise shade of a colour different or
distinguishable from the colour.
So these things cannot be separated from the
line.
So abstract ideas of lines are impossible.
(By similar argument, all ideas that involve
abstracting from precise degrees are impossible.)
Note that the “difference principle” is most
plausible when ideas are considered to be
images.
Hume’s Arguments to Confirm
Berkeley’s Account of Abstract Ideas,
cont.’d
Hume’s third argument against abstract
ideas:
If we could form an idea of an object with no precise
degree of quality or quantity, then such objects could
exist.
(because anything that we can form a distinct
idea of must be possible)
But no such objects can exist. (As everyone agrees.)
So we can form no ideas of objects with no precise
degree of quality or quantity.
“to form the idea of an object, and to form an idea simply
is the same thing; the reference of the idea to an object
being an extrinsic denomination, of which in itself it bears
no mark or character.”
So we can form no ideas that have no precise degree
of quality or quantity.
So we can form no abstract ideas.
Hume’s Account of General Ideas
A general idea is a particular idea associated
with a general term.
Hearing general term = (forming a particular
idea) + (experiencing a “custom”)
The “custom” does not produce infinitely
many more ideas or even any more
ideas.
It instead consists in a disposition to form
any of the many (but not infinitely many)
ideas that have been associated with
that term in the past.
The Disjunction Problem
Suppose I form an idea of a particular
triangle.
What makes it a general idea of a triangle
as opposed to a shape or a colour?
Hume’s Reply
The custom (disposition) aroused by the
general term is what makes the particular
idea general.
Hume’s First Argument for “Scepticism with
Regard to the Senses”
A “natural instinct or prepossession”
induces us all to believe that our
perceptions are themselves external
objects, that continue to exist unperceived.
But philosophical reflection shows us that
this cannot be so.
(Chief among the reflections Hume
mentioned is one having to do with
the visual perception of magnitude
— how can we think that the
perception is the object when the
perception constantly changes?)
So philosophers maintain that our
perceptions are instead caused by the
objects and (sometimes) (more or less)
resemble them.
But this claim is without any foundation in
reason
 because we know for a fact that many of
our perceptions (e.g., dreams) have no
such cause
 because causal inference can only be
based on past experience of a constant
conjunction between types of
antecedent and consequent events,
but in this case we have never
experienced the antecedents (the
external objects)
The claim is furthermore without any
foundation in common sense or natural
instinct
Hume’s Second Argument for “Scepticism
with Regard to the Senses”
All are agreed that the sensible qualities are
merely perceptions that have no existence
apart from being perceived.
So if there are external bodies, they must
have only the primary qualities (which are
modes of extension and solidity).
But extension cannot exist apart
from its parts, which are ultimately
points.
And these points would be nothing
were they not coloured or solid
Similarly, solidity is either just a
sensible quality (a feeling of
pressure) or the disposition to resist
penetration, which presupposes
motion of extended shapes & hence
colour and solidity (once again)
So there can be no external bodies (at least
none that have any qualities we can
conceive of).
(The only way to avoid this conclusion is to
accept abstract ideas of extension, which
have already been shown to be
impossible.)
Johnson’s Berkeleyanism
Minds are thinking active beings,
known by means of a “notion” obtained
from self-consciousness
Sensible objects are collections of simple ideas
obtained from the senses and imposed on us
independently of our wills by some greater
spirit.
These objects are not pictures of externally
existing things, but just are the real things
(At least, the only real things we are
concerned with)
Because supposing otherwise leads to
scepticism
They are nonetheless only copies of
archetypes in the divine mind.
(We do not see the ideas in the mind
of God)
Johnson’s Berkeleyanism, cont.’d
Pure intellect is a power of conceiving
abstracted [!] or spiritual objects, relations, and
acts of mind.
Spiritual objects (soul, God, agent) are
collections of simple intellectual notions, just
as sensible objects are collections of simple
ideas of sense.
Moral relations (justice, charity) are
perceived by the eyes of the mind (the
intellect) in the same way spatial relations
are perceived by the senses.
The intellect is as passive in the reception of
intellectual truths regarding the spiritual & moral
world as the senses are regarding the natural
world.
And these truths are likewise dependent on
God.
Johnson’s Berkeleyanism, cont.’d
We get our notions of ourselves by
comparing our other ideas & notions with
one another.
This comparison also gives us the abstract
notion of being in general.
In forming this and other abstract notions,
we rely on certain “first intellectual
principles” that flow from the divine mind.
(It is not immediately obvious how
this is consistent with Johnson’s
Lockeian view that the mind is
originally a blank slate that only
begins to acquire ideas and notions
as a consequence of experience)
Reid’s Account of
Berkeley’s Place in the History of Ideas
Berkeley (and Hume) were the ones who
first showed us that the theory of ideas …
(the theory that the immediate
objects of perception are mental
images)
… has certain untoward consequences:
 scepticism concerning the
existence of an external world
 scepticism concerning the
existence of other minds
 scepticism concerning the
existence of my own mind
Reid’s modus tollens
When a belief leads, by means of a valid
argument, to absurd conclusions, you ought
to suspect that there is something wrong
with the belief.
The theory of ideas leads us to absurd
conclusions.
What justification do we really have for
supposing that the immediate objects of
perception are mental images?
Berkeley’s Reply:
Dialogues I
Reid’s Account of Mental Operations
A sensation is a state of feeling
pain is paradigm
It exists only in the mind and only when it is
perceived.
When I touch a hard object I experience a sensation
pain or a sensation of pressure
But I also conceive that the object consists of parts
that resist relative motion.
I do not feel this. It is not a sensation.
It is something I believe about the cause of
my sensation.
The occurrence of this belief is not otherwise
to be explained than by saying that I am
simply innately so constituted as to form that
belief on that occasion.
Reid’s Use of the Likeness Principle
A mind is an unextended an indivisible
substance.
Neither extension, nor any image of
anything involving extension, can exist in an
unextended indivisible substance.
(Nothing like what is extended can
be like anything that is mental.)
The most that can exist in a mind is
therefore an unextended act of conceiving
an object that is entirely distinct from this
act in being extended.
Reid’s Account of Mental Operations,
cont.’d
Similarly, when I see an object I experience a
sensation of colour.
But I also conceive that the cause of this
sensation exists at a position in ambient space
(a position pointed to by a line that
originates from the affected part of the
retina and passes through the center of
the eye)
Sensation and the conception that sometimes
accompany it are very different.
 sensation does not refer to an object
 conception does
While a conception cannot exist apart from
being conceived by some mind, the object of
the conception can.
Reid’s Critique of Berkeley
Berkeley failed to recognize the distinction
between sensation and perception
(conception + belief).
He instead accepted the existence of a
sole, hybrid entity, existing in the mind like
a sensation but possessing extension &
solidity like a conceived object.
But he had no argument to justify this
supposition and it is contrary to what is
revealed by careful introspection on mental
operations.
Can I conceive an extended object without
conceiving it as coloured or defined by
tactile sensations?