Last Update: 13 April 2011
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This essay was written as an elaboration of my introductory lecture on this topic for my Philosophy of Computer Science course.
In this essay, I want to cash out the technical sense of modern, analytic, Western philosophy.
They were willing to teach anything (whether it was true or not) to anyone, or to argue anyone's cause (whether their cause was just or not), for a fee.
Socrates also wanted to teach and argue, but only to seek wisdom: truth
in any field.
The word 'philosophy' comes from Greek roots meaning
"love of [philo] wisdom [sophia]".
The reason that Socrates only sought wisdom rather than claiming
that he had it (like the Sophists did) was that he believed that
he didn't have it:
He claimed that he knew that he didn't
know anything (and that, therefore, he was actually wiser than those who
claimed that they did know things but really didn't).
Plato (430–347 B.C.) was Socrates's student. In his book, Republic, Book V, line 475c, he said:
This raises several questions:
Let's look at each of these, beginning with the second.
But how do we access "reality"?
How can we do the "pattern matching"
between our beliefs and reality?
One answer is by sense perception
(perhaps together with our beliefs about what we perceive).
But sense
perception is notoriously unreliable (think about optical illusions, for
instance).
And one of the issues in deciding whether our beliefs are
true is deciding whether our perceptions are accurate (i.e., whether
they match reality).
So we seem to be back to square one, which gives rise to the coherence theory.
i.e., they "cohere" with each other and all evidence.
(Sometimes this
is called a "pragmatic" theory of truth.)
Note that observation
statements (i.e., descriptions of what we observe in the world around
us) are among the claims that must be mutually consistent,
so this is
not (necessarily) a "pie-in-the-sky" theory that doesn't have to
relate to the way things really are.
Which theory is correct?
Einstein said, "The search for truth is more precious than its
possession". In a similar vein, the mathematician K.F. Gauss said,
One reason that this search will never end
In fact, the more questions you answer, the more questions you can ask:
The physicist John Wheeler said,
And the US economist and social philosopher Thorstein Veblen said,
This is related to Socrates's view of the philosopher as
"gadfly", investigating the foundations or reasons for beliefs and for
the way things are, always asking "What is X?". Of course, this
got him in trouble:
One moral is that philosophy can be dangerous. As Eric Dietrich puts
it:
I.e., being rational requires logic.
There are two basic kinds of rationality:
There is also, I think, a third kind, which I'll call "psychological" or
maybe "economic", and which is at the heart of knowledge representation
and reasoning in artificial intelligence (AI).
Premises P1, …, Pn deductively support
(or "yield", or "entail", or "imply")
a conclusion C
C must be true if all of the Pi are true;
i.e., C is true iff the Pi are "truth preserving".
I will use the symbol
"D" to represent this relation between truth-preserving premises
and a conclusion that is deductively supported by them.
E.g., P, P→C
D C.
E.g.: "Today is Wednesday. If today is Wednesday,
then we are studying philosophy. Therefore (deductively),
we are studying philosophy."
Note that C can be false! It only has to be true
relative to the premises (i.e., true relative to its context).
Also, any or all of the Pi can be false!
A deductive argument is said
to be "sound" iff it is valid and all of the premises are
true. So, a deductively valid argument can have any or all of
the premises false, as long as—if they were true,
then the conclusion would have to be true.)
Also, the Pi can be irrelevant to C! But that's not
a good idea, because it wouldn't be a convincing
argument. ("Relevance logics" are one way of dealing with
this problem.)
E.g., Red(ball1), …, Red(ball999999)
I Red(ball1000000)
Unlike deductive inferences, inductive ones do not guarantee
the truth of their conclusion.
In another form of abduction,
from observation O1 made at time t1,
Like inductive inferences, abductive ones do not guarantee
the truth of their conclusion. Moreover, abductive
inferences are deductively invalid! But they are at
the heart of the scientific method for developing
and confirming theories.
In monotonic logics (such as deductive logics), once you have
proven that a conclusion C follows from a premise P, then it
will always so follow.
But in non-monotonic logic, you might infer
conclusion C from premise P at time t0, but,
at later time t1, you might learn that it is not
the case that C. In that case, you must revise your beliefs.
E.g., you might believe that birds fly and that Tweety is a bird,
from which you might conclude that Tweety flies. But if you then
learn that Tweety is a penguin, you will need to revise your
beliefs.
This is
more "psychologically valid" than the other forms of reasoning.
Is there anything to be said in favor of not being rational?
Suppose you have to decide between two apparently equal choices that you
simply cannot decide between. This is similar to a problem known as
"Buridan's Ass":
My favorite way out of such a quandary is to imagine throwing a coin and
seeing how you feel if it lands heads up:
For another consideration, consider Andrew N. Carpenter's
response to the question
After all, science is also a search for truth by
rational means.
Is the experimental or empirical methodology of science "rational"?
It's not deductive.
Science is philosophy, as long as experiments and empirical
methods are considered to be "rational" and yield truth. Physics and
psychology, in fact, used to be branches of philosophy: Newton was a
professor of "natural philosophy", not "physics", and psychology split
off from philosophy only at the turn of the 20th century. The
philosophers Aristotle and
Kant wrote physics books. The physicists Einstein and Mach wrote
philosophy. And the "philosophy naturalized" movement in contemporary
philosophy (e.g., Quine) sees philosophy as being on a continuum with science.
But science is not philosophy if experiments don't count as being
rational and only logic counts, or else if philosophy is considered to
be the search for universal or necessary truths, i.e.,
things that would be true no matter what results science came up with or
what fundamental assumptions we made.
There might be conflicting world views (e.g., creationism vs. evolution,
perhaps). Therefore, the best theory is one that is consistent,
that is as complete as possible (i.e., that explains as much as
possible), and that is best-supported by good evidence.
You can't refute a theory. You can only point out
problems with it and then offer a better theory.
Suppose that you infer a prediction P from a theory T and a hypothesis
H, and then suppose that the prediction doesn't come true (your
experiment fails; i.e., the experimental evidence is that P is not the
case). Then, logically, either H is not the case or T is
not the case (or both). And, since T is probably a complex conjunction
of claims A1 & … & An, then, if T is not the case, then
at least one of the Ai is not the case. In other words, you need not
give up a theory; you only need to revise it.
Could (should?) philosophy be scientific, i.e., experimental?
There is a relatively recent movement (with some older antecedents) to
have philosophers do scientific (mostly psychological) experiments in
order to find out, among other things, what "ordinary" people (e.g.,
people who are not professional philosophers) believe about certain
philosophical topics. My feeling is that this is not really philosophy,
but rather an (interesting) branch of cognitive science. For more
information on this movement, see:
As the computer scientist R.W. Hamming warned,
"In science and mathematics, we do not appeal to authority, but rather
you are responsible for what you believe."
Or, as
Jim Holt (2009)
puts it: "Broadly speaking, philosophy has three
concerns: how the world hangs together, how our beliefs can be
justified, and how to live." The first of these is metaphysics, the
second is epistemology, and the third is ethics.
The main branches of philosophy are:
Do "non-existents" (e.g., Santa Claus) exist? We can
and do think and talk about them. Therefore, whether or not they
"exist" in any sense, they do need to be dealt with.
See
Quine 1948.
See also
Hirst 1991, for a survey of the AI approach to this.
(And see
"SNePS and Knowledge, Belief, & Intensionality" for some
papers on our AI approach to these issues.
Philosophy of language tries to answer "What is
language?", "What is meaning?". It has large overlaps with linguistics
and with cognitive science (including AI and computational
linguistics).
Philosophy of mind tries to answer "What is "the" mind?",
"How is the mind related to the brain?".
And, for any X, there is a philosophy of X, which
is the study of the fundamental assumptions, methods, and
goals of X, where X could be: mathematics (what is a number?
is math about numbers, numerals, sets, structures?), science,
physics, biology, psychology, etc., including, of course,
AI and computer science.
(X, by the way, could also be...philosophy! The philosophy of
philosophy, also known as "metaphilosophy", is exemplfied by this very
essay, which is an investigation into what philosophy is and how it can
be done. Some people might think that the philosophy of philosophy is
the height of "gazing at your navel", but it's really what's involved
when you think about thinking, and, after all, isn't AI just
computational thinking about thinking?)
(Click on the link to see one philosopher's answer :-)
Not necessarily; i.e., we may not be able to find it.
But I also believe that finding it is not necessary; i.e., we may not
have to find it:
Philosophy is the search for truth.
(For more on the importance
of search over success, see my
website on William Perry's theory of intellectual development
and
Rapaport 1982.)
"It
is not knowledge, but the act of learning,
not possession but the act
of getting there,
which grants the greatest enjoyment."
(which is different from
saying that it will not succeed)
is that you can always ask "why?";
i.e., you can always continue inquiring.
"We live on an island of knowledge
surrounded by a sea of ignorance.
As our island of knowledge grows, so
does the shore of our ignorance.""The outcome of any serious reserch can only be to make two questions
grow where only one grew before."
His claims to be ignorant were thought (probably
correctly) to be somewhat disingenuous.
As a result, he was tried,
condemned to death, and executed. (For the details, read Plato's
Apology.)
Thinking about the Big Questions is serious, difficult business. I tell
my philosophy students: "If you like sweets and easy living and fun
times and happiness, drop this course now. Philosophers are the hazmat
handlers of the intellectual world. It is we who stare into the abyss,
frequently going down into it to great depths. This isn't a job for
people who scare easily or even have a tendency to get nervous."
(Personal communication, 5 October 2006.)
Mere statements (i.e., opinions) by themselves are
not rational.
Rather, argumentsreasoned or
supported statementsare capable of being rational.
But there are lots of different (kinds of) logics, so there are lots of
different kinds of rationality.
iff
(A deductive argument
is said to be "valid" iff it is impossible for all of the premises
to be true but the conclusion false.
From observation O made at time t1,
and from a theory T that
deductively or inductively entails O,
one can abductively
infer that T must have been the case at earlier time t0.
and from observation O2 made
at time t2,
one can abductively infer that O1 might have
caused or logically entailed O2.
This kind of reasoning is more "psychologically real" than
any of the others. It also underlies what the economist/AI
researcher Herbert Simon called "satisficing" (or being satisfied with
having a reasonable answer to your question rather than an optimal one),
for which he won the Nobel Prize in Economics.
According to one version, the ass (as in "donkey") was placed equidistant between
two equally tempting bales of hay
and died of starvation because it
couldn't decide between the two of them.
If you would rather that it had landed tails up,
then you know what you
would have preferred,
even if you had "rationally" decided that both
choices were perfectly equally balanced.
But it yields highly likely conclusions, and
is often the best we can get.
My major professor,
Hector-Neri
Castañeda, used to say that philosophy should be
done in the first person, for the first person. So, philosophy is
whatever I am interested in, as long as I study it in a rational
manner and aim at truth (or, at least, aim at the best theory).
Philosophy also studies things that are not studied by any
single discipline: the Big Questions: What is truth? What is
beauty? What is good (or just, or moral, or right)? What is the meaning
of life?
Are there any topics that philosophy doesn't touch on?