Epistemology:
What
do you know?
I
know I have a hand.
I
know that Paris is the capital of France.
I
know that gold’s atomic number is 79.
I
know that a rook can move horizontally or vertically on the chess board.
I
know what a rose smells like.
I
know how to ride a bike.
I
know where I live.
I
know who I am. (most days).
But
all these really refer to importantly different “ways of knowing” or “kinds” of
knowledge. In Western philosophy, we
have concentrated mostly of “propositional” knowledge. By the way, a “propositional belief” is a
“that” belief: I belief that… The “proposition” is what comes after the
“that.” e.g.
that the Earth revolves around the sun, that Tuesday comes after Monday; that the
square root of four is two. So much
emphasis on propositional knowledge has lead
to the impression that all knowledge is propositional and that anything worth knowing can be
expressed in propositions. (Those “that”
phrases I was talking about.) I think
this is a problem, but we’ll be talking more about that throughout the
semester.
Plato
argues that knowledge is best understood as “true, justified belief.[1]” That is to say that Jose knows that Mary is
guilty of cheating on her quiz is to say:
- Jose believes that Mary is
guilty.
- It is true that Mary is guilty.
- Jose has a good reason
(justification) for his belief that Mary is guilty.
Note: Kn=
TJB. This is referred to as the “Traditional Account of Knowledge.”
As
I say, this has been widely accepted as THE correct understanding of
knowledge for the better part of Western history. More recently it has been challenged[2]
and we will be looking both at the traditional account of knowledge and its
challenges. Today I want to concentrate
on how the traditional understanding of knowledge has
Rationalism and
Empiricism
So
how do we acquire knowledge? How do we
avoid deception and error? Plato
suggested that the senses were deceptive, and that the most reliable knowledge
came from a priori reason and introspection. He can point to the reliability of math and
geometry to prove his point. This is
characteristic of one of the two great traditions in Western epistemology: Rationalism.
But
Plato’s best student and best critic was the philosopher Aristotle. In contrast to Plato, Aristotle held that the
best way to come to know objective truth, indeed the ONLY way to come to know
objective truth, is via sensory experience.
This is the second of the two great traditions: Empiricism. These two
viewpoints battled against one another for the next 2000 years.
The
three major tenants of Rationalism are (1) that there exists such a thing as “innate
ideas,” ideas that are in some sense born in us, (2) that the senses are an
unreliable source of knowledge, and (3) that the most reliable source of
knowledge is our a priori reasoning and introspection.
The
three major tenants of Empiricism are (1) the denial of any such thing as
innate ideas, (2) a confidence in the ability of the senses to provide us with
genuine knowledge, and, (3) while a priori reason
is fine as far as it goes, it's extremely limited with respect to giving us
useful knowledge about the world around us, confined as it is to largely
vacuous logical tautologies.
|
Rationalism |
Empiricism |
|
There are
Innate Ideas |
There are no
innate ideas |
|
The Senses
are a poor, unreliable means to knowledge |
The senses
are a reliable, indeed the only means to knowledge. |
|
The most
reliable means to gain knowledge and truth is via a priori reason and
introspection |
A priori reasoning is fine as far as it goes,
but it is very limited as to what it can provide us in the way of
knowledge. The most reliable way to useful knowledge is through
observation and experience. |
|
Representative
Philosophers: |
Representative
Philosophers: |
|
|
Over
time, Empiricism came to dominate philosophy in the United Kingdom, and
eventually the United States. It is this
tradition, I contend, that has had the greatest influence on contemporary
popular thinking about knowledge, truth and
justification in the United States.
There are several features of this view that I would like to highlight
and ask you to examine. The first of
these is the nature of perception.
Locke on Innate
Ideas (a.k.a.: How we DON’T get
knowledge according to Locke)
Both Plato and Descartes appealed to the doctrine of innate knowledge. But Aristotle denied that there was an ‘innate knowledge’ asserting instead the “nothing is in the mind that wasn’t first in the senses.”
Locke agrees with Aristotle on this point. In An Essay Concerning Human Understanding (1689), he gives a systematic case against innate knowledge, and argues for the Empiricist doctrine that the senses alone are the source of all knowledge.
Empiricists maintain that the only way to come to know the world is through sensory experience. He agrees with Aristotle and St. Thomas Aquinas[3]- that:
“Nothing is in the mind without first having been in the senses.”
Note: This was called “The Peripatetic Axiom”
It is found in De veritate, q. 2 a. 3 arg. 19. Thomas Aquinas adopted this principle from the Peripatetic school of Greek philosophy, established by Aristotle.
Latin: "Nihil est in intellectu quod non prius in sensu."
Unlike Descartes, who sought absolute, indubitable certainty (Justification must be apodictic.) , the modern Empiricist John Locke was after something more modest: probability/ plausibility. Like modern scientists today, Locke was not looking for beliefs that could be proven true beyond a shadow of a doubt. Rather he is content to call knowledge those things we can demonstrate true beyond a reasonable doubt.
Summary of Locke’s Case Against Innate Ideas:[4]
In An Essay Concerning Human Understanding (1689), he gives a systematic case against innate knowledge, and argues for the Empiricist doctrine that the senses alone are the source of all knowledge.
“It is an established opinion
amongst some men, that there are in the understanding certain ‘innate
principles’; some primary notions … characters, as it were stamped upon the
mind of man; which the soul receives in its very first being,
and brings into the world with it.” [5]
However, Locke argues we can only perceive color with our eyes. If so, it seems inconsistent to say we have or could have innate knowledge of color. Locke considers those who suggest “that there are certain principles, both speculative and practical, (for they speak of both), universally agreed upon by all mankind“. If this is so, then is seems reasonable to suppose that all people would share certain innate principles.
Locke points out two problems with this argument:
1. Even if certain principles are universally held, that does not follow from this that these principles are innate.
There could be other explanations why certain principles are universally held. But perhaps more problematic…
2. There simply are no such universally held principles.
He considers some very widely held beliefs:
“I shall begin with the speculative, and instance in those magnified principles of demonstration, “Whatsoever is, is,” and “It is impossible for the same thing to be and not to be”; which, of all others, I think have the most allowed title to innate. These have so settled a reputation of maxims universally received, that it will no doubt be thought strange if any one should seem to question it. But yet I take liberty to say, that these propositions are so far from having an universal assent, that there are a great part of mankind to whom they are not so much as known.”
Locke argues that even the law of identity and the law of non-contradiction are NOT universally held. He claims that “children and idiots have not the least apprehension or thought of them“. If this is the case, we seem to be compelled to assert some people will have “principles in their minds” of which they never become aware. But, as Locke puts it, “it seeming to me near a contradiction to say, that there are truths imprinted on the soul, which it perceives or understands not”
But perhaps one need fully functioning rational capacities to fully appreciate these innate ideas which is why children and the mentally impaired do not assent to them. But Locke goes on to critique this defense.
First, he interprets the statement “that all men know and assent to them when they come to the use of reason” in two ways:
1. That reason is used to discover these innate principles.
But this would imply that all knowledge gained from reasoning would then be innate. This would either contradict the innate view that only universally held knowledge (i.e. the law of identity) have innate principles or it implies that knowledge gained by reasoning does not require the discovery of innate principles.
2. When reason is used these principles become apparent.
On this interpretation, Locke has two lines of critique.
But Locke maintains that in actuality, when one is coming to reason as one matures into adulthood, people discover the law of non-contradiction. They
“are indeed discoveries made and verities introduced and brought into the mind by the same way, and discovered by the same steps, as several other propositions, which nobody was ever so extravagant as to suppose innate.”
Since there are no innate ideas, Locke claims that we start life with a blank slate, "tabula rasa.“
This reference may not be as familiar to you as it is to me. I can recall my grandmother talking about taking her “slate” to school. Children in those days would learn their letters and arithmetic on handheld chalkboards, or “slates.” They were sort of the IPADs of the day and much cheaper than paper. A “blank slate” is merely a blank chalkboard, blank, but ready to be written upon and “receive” information. But then again, “chalkboard” too may be a faded cultural reference these day as well. (Sigh.)
John Locke
and the Causal Theory of Perception (Where do our ideas come from?)[6]
Locke
points out that there is the world and there are our ideas about the
world. He agrees with Descartes
that we never gain direct access to the objective world. He denies “Direct (Naive) Realism.”
This
places critical importance on determining: What is the connection between
reality and our mind? To this end, Locke
offers his “Causal Theory of Perception.”
Causal Theory of Perception
‑
the world interacts with out perceiving organs and causes our ideas in our
minds.
Locke
theory of perception he thought accorded well with the physical theories of his
slightly younger contemporary, Sir Isaac Newton (1642 - 1726). It should be noted that Locke uses the word
“idea” very broadly. Nearly any mental
item can count as an idea: a concept, a memory or even a simple sensation such
as “salty taste.”
·
The only way to come to know the world is through sensory
experience.
·
Agrees with Aristotle and St. Thomas Aquinas- that,
“Nothing is in the mind without first having been in the senses.”[7]
·
Locke claims that we start life with a blank slate,
"tabula rasa[8]."
·
Points out that there is the
(1) world
and
(2) ideas
about the world.
• Agrees
with Descartes that we never gain direct access to the objective world. He denies “Direct (Naive) Realism.”
This
places critical importance on determining: What is the connection between reality and
our min?
This
this end, Locke offers his “Causal Theory of Perception.”
Causal
Theory of Perception ‑ the world interacts with out perceiving organs
and causes our ideas in our minds; Locke’s use of the word “idea” is very
broadly- nearly any mental item can count as an idea, a concept, a memory or
even a simple sensation such as “salty taste.”
So
then, the world causes our ideas about (perceptions of) it.
Here
is a crude rendering of how this was
supposed to work. You have an object
(say an apple) and it interacts with our perceiving
organs (say our eye) and causes in us the perception of an apple.
Note: our ideas about
reality are different from reality itself; ideas are mental, but reality is
extra mental.
It
is therefore crucial to examine the connection between the two: perceptions and
extra-mental reality in detail. What is the relationship between our ideas and the
world? How does the one give us knowledge about the other? His concerns are not really that different
from those of Rene Descartes here; however, Locke’s resolution is radically
different. Unlike Descartes, who sought
absolute, indubitable certainty (justification must be apodictic), Locke was
after something more modest: probability/ plausibility. Like good scientists today, he was not
looking for beliefs that could be proven true beyond a shadow of a doubt. Rather he is content to call knowledge those
things we can demonstrate true beyond a reasonable doubt.
Our Mental Ideas and the
Extra-mental Reality
Locke is offering a version of “Representational
Realism” The mind does not “directly
perceive the world, but rather only perceives mental representations. What the mind has direct access to then is a
“representation” of reality, but not a direct apprehension of reality as such. Our perceptions are mental representations that are supposed to give us information about the
objective (mind independent) world.
Thus, it is very important to get clear about our
mental content and how we may infer from direct apprehension of our mental
content to claims about the objective, mind-independent world. To this end, Locke offers us certain
distinctions as we sort through the contents of our minds and perceptions.
First, Locke suggests that the world causes our ideas about (perceptions of) it. (Hence his “Causal Theory of Perception”) Next, he begins to examine these ideas and
what their possible relationship to the extramental world could be. He draws several distinctions that he thinks
are important to knowing how we can go from immediate knowledge of our mental
representations to knowledge of mind-independent reality.
Simple and Complex Ideas:
Our
“ideas” come in two varieties according to Locke:
Simple
ideas are idea that cannot be broken down into any component
parts. For example, the idea of
“white.” I cannot explain “white” to
you; I can only show examples of white and hope you get it. Simple ideas arise from simple sensations.
Complex
ideas are ideas that can be broken down into component
parts. For example, the idea of
(perception of) a unicorn. I can
explain the idea of an unicorn to you. To explain a unicorn all one must do is take
the ideas of a horse, white, a horn and combine them in a certain way. The “idea” of an apple (i.e.
one’s perception or experience of an apple) might include the simple ideas of
red, round, sweet, solid, etc.[9]
Primary and Secondary Properties:
Our
experience of objects reveals two kinds of properties: Primary Properties and
Secondary Properties.
Primary Properties
·
Properties of objective, extra-mental reality.
·
These are the qualities of the object independent of who
or whether anyone is perceiving the object. Thus, these are independent of
perception.
These
are the intrinsic features, those they really have, including the "Bulk,
Figure, Texture, and Motion" of its parts. (Essay II viii 9) Since these features are inseparable from the
thing even, when it is divided into parts too small for us to perceive, the
primary properties are independent of our perception of them. When we do
perceive the primary properties of larger objects, Locke believed, our ideas exactly
resemble the qualities as they are in things. He says:
“From this we can easily infer that the ideas of the
primary qualities of bodies resemble them, and their patterns really do exist
in the bodies themselves;[10]
Secondary Properties
These
are NOT, strictly speaking, properties of objects at all, Rather they are properties
of our peculiar experience of reality, that is, of our perception. These properties only occur in the mind of
the perceiver and only at the moment of the
perception. They endure only as long as the perception endures. Thus, these are perception dependent. Think of the pain you experience when you get
a sliver. It is a feature of your experience
of the sliver, but NOT a feature of the sliver.
Alternatively, think of that experiment you probably did in middle
school, where the teacher has you put your left hand in a pan of very warm
water and your right hand in a pan of ice cold water
and between them sits a pan of water at room temperature. Then you were told to
withdraw your hands from both pans and plunge them into the center pan. Your left hand experiences the water as cool, whereas your right
hand experiences the very same water as warm. But this demonstrates that
neither cool nor warm our actual properties of the water, but rather only
properties of your peculiar experience of the water at this
time.
Thus,
these are NOT qualities in the thing itself, but rather evidence powers the
object has to produce in us these ideas of
"Colors, Sounds, Smells, Tastes, etc." (Essay II viii 10) In these
cases, our ideas do NOT resemble their causes, which are, in fact, nothing
other than the primary qualities of the things. The shape of the sugar molecule,
for instance, has the power to create in us a sweet sensation. (Though not in cats.) In these cases, our ideas (e.g.
sweet) do not resemble their causes (e.g. shape).
“It is no more impossible to conceive that God should
attach such ideas to motions that in no way resemble them than it is that he
should attach the idea [= ‘feeling’] of pain to the motion of a piece of steel
dividing our flesh, which in no way resembles the pain.[11]
Tertiary Properties: (Don’t worry
about this too much.)
“because the powers or capacitys of things which too are all conversant about
simple Ideas, are considerd in the nature of the
thing & make up a part of that complex Idea we have of them therefor I call
those also qualities” (Draft A 95: D I 83).
Powers
or capacities are counted as qualities because people tend to think
that they are parts of the natures of things and because the corresponding
ideas are constituents of our complex ideas.
By saying that he “also” calls powers ‘qualities’ (properties), Locke
implicitly contrasts powers with the first sort of qualities. Tertiary quality’ is what commentators call
Locke’s “third sort” of quality (E II.viii.10: 135), which he describes as
“The Power that is in any body, by Reason of the
articular Constitution of its primary Qualities, to make such a change in the
Bulk, Figure, Texture, and Motion of another Body, as to make it operate on our
Senses, differently from what it did before” (E II.viii.23: 140).
The powers,
or tertiary qualities, of an object are just its capacities to cause perceptible
changes in other things.
·
passive power = the capacity a thing has for being
changed by another thing (301), e.g., the power of wax to be melted by the sun.
(We receive the idea of this power from almost all sensible things.)
·
active power = the capacity a thing has for changing
another thing. (301)
For
example the power of sun to melt wax; according to
Locke, these ideas which are the tertiary qualities do not resemble the powers
in things that produce these ideas.
Since only the primary properties of our perception
tell us anything objective about the world we must be
careful to distinguish these from secondary properties. Trying to determine whether or not a object possesses a secondary
property or not, or to what degree is a waste of time since it does not,
cannot, possess it to any degree. (E.g. Is the soup really too salty?) But
then to avoid such silly questions and concentrate on the serious ones, that
is, to engage in serious inquiry it is important we distinguish primary and
secondary properties of our experience.
Two ways to tell the Difference
Between Primary and Secondary Properties:
Since
only the primary properties of our perception tell us anything objective about
the world we must be careful to distinguish these from
secondary properties. Trying to
determine whether or not a
object possesses a secondary property or not, or to what degree is a waste of
time since it does not, cannot, possess it to any degree. Is the soup really too
salty? ( Silly question.) But then to
avoid such silly questions and concentrate on the serious ones, that is, to
engage in serious inquiry it is important we distinguish primary and secondary
properties of our experience.
1.
To change a primary property of the object you have actually
have to change the object itself, but to change a secondary property one
need only change the conditions of perception.
2.
Primary properties can be experienced by more than on sense, but secondary
properties can be experienced by one sense alone.
Consider
the idea (perception) of an apple again:
It
is a complex idea composed of, among other simple ideas, the ideas:
· Red
· Round
· Sweet
· Solid.
According to the criteria Locke provides, which of the
apple’s perceived properties are primary (really “in” the apple, and which are
secondary (perception dependent, having no reality apart from perception)?
So of the four qualities listed above,
which are which?
·
Red is secondary- (I would no longer see red if I were to
change the lighting or I stared at a bright green
poster board. Also
I have access to the color of things through only one sense: vision.)
·
Round is primary- (I would have to cut or smash the apple
to change it’s shape. Also, I have both visual and tactile access
to the shape.)
·
Sweet- secondary.
·
Solid- primary.
So we must be careful about
distinguishing primary and secondary and making claims about reality. Serious inquiry (science) should confine
itself to primary properties alone.
Thus,
for Locke then, we gain knowledge of the objective world via simple sensations
caused in us by the objects which give rise to the simple and complex
ideas. These, in turn, inform us of the
primary properties of the object as well
as provide us with the secondary properties given to us in experience. But there is no point is arguing about
whether an object has a secondary property or not, or to what degree. (In point of fact, they NEVER
have them.)
Notice
there is no point to us arguing about whether the soup is “too salty” or not
since the very same soup may cause in me a “too salty” secondary property, but
in you cause a “not salty enough” secondary property. Salty taste is a perception dependent,
secondary property, existing only in the mind of the perceiver at the time of
perception. As such is it not the proper
subject for serous or scientific discussions.
Further, the very same soup might not even cause in me a “too salty”
sensation next time I taste it if, for instance, I drink something even saltier
than the soup in the meantime or I just get used to the saltiness of the soup. [12]
Since
secondary properties are not actually properties of objects, but rather merely
properties of the perception of objects, they are not fixed and stable. If we had evolved differently, say as
sentient vegetation, “salty taste” would not happen at all. Had we all evolved like snakes, “sound”
wouldn’t happen at all. Though sound waves would continue to be
just as they are. Therefore, serious
inquiry (science) should confine itself to primary properties.[13]
Note: This view of knowledge suggests that the sum
of what can be known are objective facts (facts about primary properties of the
world) and perhaps math. But if you are
not talking about these matters, you are not in the business of saying anything
true or false. Everything else is relegated
to “matters of opinion.” More on this
later.
So,
if a tree falls in the woods and no one is there to hear it, does it make a
sound? No. Had we all evolved like snakes, “sound”
wouldn’t happen at all. – at least our notion of sound. But as I say, sound waves would continue to
be just as they are.
Therefore,
(the new) science (serious inquiry) should confine itself to
primary properties. Recall that Locke is
writing at a time when it was still common for scientists to identify chemicals
by taste.
What
are the “primary properties” properties of?
Locke
realized that there must be some “ground” for these properties. That is, the primary properties must be
property of something. Properties
cannot exist on their own, as Aristotle had noted. If the mind independent apple is really a
solid round something, what is that something?
What, precisely, is solid and round?
So Locke’s answer is that primary
properties (these extra mental, non-perception-dependent properties), were
properties of “Physical Substance.”
Physical
Substance: (Stuff) – but we can know very little about physical
substance as such since we never directly perceive it. We only perceive our perceptions
and these are at most merely primary properties, not the substance itself. Presumably the primary properties of physical
substance are what CAUSE our perceptions, but physical substance in not
accessed directly in perception.
Locke
uses and old metaphysical notion of substance: that of which one
predicates. Nevertheless, since we do
not directly perceive physical substance, there really isn’t much more that we
can know about it. Locke says of
physical substance that it is “something that I know not what.”[14]
“if any one
will examine himself concerning his Notion of pure Substance in general, he
will find he has no other Idea of it at all, but only a Supposition of he knows
not what support of such Qualities, which are capable of producing simple Ideas
in us; which Qualities are commonly called Accidents.[15]
Therefore:
Our
ideas are caused by the physical substance; all ideas are mediated by your
senses; what causes the ideas is the physical substance that never directly
have contact with. While our mental
experience is rich with both primary and secondary properties, the objective
world can only be said to possess the primary properties. Secondary properties would name subjective
experiences only, not the stuff of serious scientific inquiry or discourse
pertaining to objective truth.
This
Empiricist Account of Knowledge and Knowing remained and remains incredibly
influential in Western Concepts of objective knowledge and inquiry. See Logical
Positivism (but you can largely ignore the notes on Emotivism as
the end… unless you are in my Ethics or Aesthetics course.
Addendum:
Locke’s
alternative to the strict Cartesian limitation of knowledge:
The notice we have by our
senses of the existing of things without us, though it be not altogether so
certain as our intuitive knowledge, or the deductions of our reason employed
about the clear abstract ideas of our own minds; yet it is an assurance that
deserves the name of knowledge. If we persuade ourselves that our faculties act
and inform us right concerning the existence of those objects that affect them,
it cannot pass for an ill-grounded confidence: for I think nobody can, in
earnest, be so sceptical as to be uncertain of the
existence of those things which he sees and feels. At least, he that can doubt
so far, (whatever he may have with his own thoughts,) will never have any
controversy with me; since he can never be sure I say anything contrary to his
own opinion. As to myself, I think God has given me assurance enough of the
existence of things without me: since, by their different application, I can
produce in myself both pleasure and pain, which is one great concernment of my
present state. This is certain: the confidence that our faculties do not herein
deceive us, is the greatest assurance we are capable of
concerning the existence of material beings. For we cannot act anything
but by our faculties; nor talk of knowledge itself, but by the help of those
faculties which are fitted to apprehend even what knowledge is.
Locke
then answers Descartes Skepticism:
8. But yet,
if after all this anyone will be so sceptical as to
distrust. his senses, and to affirm all that we see and hear, feel and taste,
think and do, during our whole being, is but the series and deluding appearance
of a long dream, whereof there is no reality; and therefore will question the
existence of all things, or our knowledge of anything: I must desire him to
consider, that, if all be a dream, then he doth but dream that he makes the
question, and so it is not much matter that a waking man should answer him. But yet, if he pleases, he may dream that I make him this
answer, that the certainty of things existing in rerum natura when we have the testimony of our senses for it is not
only as great as our frame can attain to, but as our condition needs. For, our
faculties being suited not to the full extent of being, nor to a perfect,
clear, comprehensive knowledge of things free from all doubt and scruple; but
to the preservation of us, in whom they are; and
accommodated to the use of life: they serve to our purpose well enough, if they
will but give us certain notice of those things, which are convenient or
inconvenient to us. For he that sees a candle burning, and hath experimented
the force of its flame by putting his finger in it, will little doubt that this
is something existing without him, which does him harm, and puts him to great
pain: which is assurance enough, when no man requires greater certainty to
govern his actions by than what is as certain as his actions themselves. And if
our dreamer pleases to try whether the glowing heat of glass furnace be barely
a wandering imagination in a drowsy man's fancy, by putting his hand into it,
he may perhaps be wakened into a certainty greater than he could wish, that it
is something more than bare imagination. So that this evidence is as great as
we can desire, being as certain to us as our pleasure or pain, i.e., happiness
or misery; beyond which we have no concernment, either of knowing or being.
Such an assurance of the existence of things without us is sufficient to direct
us in the attaining the good and avoiding the evil
which is caused by them, which is the important concernment we have of being
made acquainted with them.
9. In summary, then, when our
senses do actually convey into our understanding any
idea, we cannot but be satisfied that there doth something at that time really exist without us, which doth affect our senses,
and by them give notice of itself to apprehensive faculties, and actually
produce that idea which we then perceive.