John
Lock (1632 -1704) was one of the three “British Empiricists” of the
Enlightenment period.[1] As am Empiricist, Locke was committed to the
idea that there were no such things as “innate ideas” and that the best, indeed
the only way, to come to know objective truth was via sensory experience.
·
The only way to come to know the world is through sensory
experience.
·
Would agrees with St. Thomas Aquinas- that, “Nothing is
in the mind without first having been in the senses.”
Note: The Peripatetic axiom: "Nothing is
in the mind without first having been in the senses" (Latin: "Nihil est in intellectu
quod non prius in sensu").
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.
·
Locke claims that we start life with a blank slate,
"tabula rasa[2]."
·
Points out that there is the (1) world and there are (2) ideas
about the world.
·
This places critical importance on determining what is
the connection between reality and our mind.
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.
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?
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 concept 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.
(Incidentally this is how Locke explained how it is that
we could think of some things that we have never directly perceived and were
never in fact ‘in our senses.” We do so
by merely recombining the component parts of the ideas of objects that we have
directly perceived.)
Primary and Secondary Properties:
Our
experience of objects reveals two kind 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.
Secondary Properties
·
Properties of our peculiar experience of reality, that
is, of our perception.
·
They are NOT properties of the object at all.
·
These properties only occur in the mind of the perceiver
at the moment of the perception. They
endure only as long as the perception endures.
Thus these are perception dependent.
Two ways to tell the Difference
Between Primary and Secondary Properties:
1.
To change a primary quality 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:
It
is a complex idea composed of, among other simple ideas, the ideas red, round,
sweet, and 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)?
·
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.
Thus,
for Locke then, we gain knowledge of the objective world via the simple and
complex ideas caused in us by the objects and they inform is of the
primary properties of the object as well
as provide us with the secondary properties given to us in experience. But this means that we must be careful about
distinguishing primary and secondary when making claims about reality. There is no point is arguing about whether an
object has a secondary property or not, or to what degree. Notice there is no point to us arguing about
whether the soup is too salty or not since the soup may cause in me a “too
salty” secondary property, but not in you.
Salty taste is a precpetion dependent,
secondary property. As such is it not
the proper subject for serous or scientific discussions. Further, it might not even cause that
sensation in me the next time I taste it if, for instance, I drink something
even saltier than the soup in the meantime. [3]
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. Therefore, serious inquiry (science)
should confine itself to primary properties.[4]
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. So his 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 they are
a merely properties, not the substance itself.
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.”
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 qualities, 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.
Diagram
of the Process Locke Envisions
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.)
[1] Locke was English. The two others were George Berkley (1685 –1753, Irish) and David Hume (1711 – 1776, Scottish)
[2] 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 would learn their letters and arithmetic on handheld chalkboards, or “slates.” There were sort of the IPODs of the day and much cheaper than paper. A blank slate is merely a blank chalkboard, blank, but ready to be written upon, receive information. But then again, “chalkboard” too may be a faded cultural reference these day as well. Sigh.
[3] What about beauty, one might ask. Is it “in the eye of the beholder?”
[4] Recall that Locke is writing at a time when it was still common for scientists to identify chemicals by taste.