What Is Philosophy?

A Brief Essay

On the web at http://www.cse.buffalo.edu/~rapaport/584/whatisphil-essay.html

William J. Rapaport

Department of Computer Science and Engineering,
Department of Philosophy,
Department of Linguistics,
and Center for Cognitive Science
State University of New York at Buffalo,
Buffalo, NY 14260-2000

Last Update: 13 April 2011

Note: NEW or UPDATED material is highlighted

This essay was written as an elaboration of my introductory lecture on this topic for my Philosophy of Computer Science course.

  1. 'Philosophy' can be an informal term:

  2. Western philosophy began in ancient Greece.

  3. Adapting this, I define 'philosophy' as the personal search for truth, in any field, by rational means.

    This raises several questions:

    1. Why only "personal"? (Why not "universal"?)
    2. What is "truth"?
    3. Why is philosophy only the search for truth? Can we succeed in our search?
    4. What does "any field" mean? Is philosophy really the study of anything and everything?
    5. What counts as being "rational"?

    Let's look at each of these, beginning with the second.

  4. What is truth?
    Two theories of truth are the correspondence theory and the coherence theory.

    1. According to the correspondence theory, truth is a relation between beliefs (or sentences, or propositions) and "reality":

        A set of propositions is true if and only if ("iff") they correspond to reality,
        i.e., iff they "match" or accurately describe reality.

        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.

    2. According to the coherence theory of truth, a set of propositions (or beliefs, or claims) is true iff:

      1. they are mutually consistent, and
      2. they are supported by, or consistent with, all available evidence;

      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?

  5. Can we find truth?
    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:

    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
    (which is different from saying that it will not succeed)
    is that you can always ask "why?"; i.e., you can always continue inquiring.

    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:

  6. What is "rational"?
    Mere statements (i.e., opinions) by themselves are not rational.
    Rather, arguments—reasoned or supported statements—are capable of being rational.

    I.e., being rational requires logic.
    But there are lots of different (kinds of) logics, so there are lots of different kinds of rationality.

    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).

    1. Deductive Logic is the main kind of mathematical rationality.

      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 "valid" iff it is impossible for all of the premises to be true but the conclusion 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.)

    2. Inductive Logic is one of the three main kinds of scientific rationality:

      • The first is deductive (see above): Mathematical rationality is certainly part of science.
      • The third is "abductive" (see below).

      • In inductive logic, P1, …, Pn |-I C iff C is probably true if all of the Pi are true.

        E.g., Red(ball1), …, Red(ball999999) |-I Red(ball1000000)

        Unlike deductive inferences, inductive ones do not guarantee the truth of their conclusion.

    3. Abductive Logic, or "inference to the best explanation", is also scientific:

        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.

        In another form of abduction, from observation O1 made at time t1,
        and from observation O2 made at time t2,
        one can abductively infer that O1 might have caused or logically entailed O2.

        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.

    4. Non-Monotonic Logic
      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.

      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

  7. Is science philosophy?

    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.
    But it yields highly likely conclusions, and is often the best we can get.

    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:

    1. Nahmias, Eddy; Morris, Stephen G.; Nadelhoffer, Thomas; & Turner, Jason (2006), "Is Incompatibilism Intuitive?", Philosophy and Phenomenlogical Research 73(1) (July): 28-53.

    2. Appiah, Kwame Anthony (2007), "The New New Philosophy", New York Times Magazine (December 9): 34, 36.

    3. Appiah, Kwame Anthony (2008), "Experimental Philosophy", Proceedings and Addresses of the American Philosophical Association 82(2) (November): 7-22.

    4. Knobe, Joshua (2008/2009), "Can a Robot, an Insect, or God Be Aware?", Scientific American Mind 19(6) (December/January): 68-71.

    5. UB Experimental Epistemology Research Group

    6. NEW Nichols, Shaun (2011), "Experimental Philosophy and the Problem of Free Will", Science 331(6023) (18 March): 1401–1403.

  8. What is the import of "personal search"?
    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).

    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."

  9. What is the import of "in any field"?
    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?

    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:

    1. Metaphysics (or ontology), which tries to answer the question "What is there?" (and also the question "Why is there anything at all?"). Some of the things that "there might be" include: properties (and these might be "accidental" or "essential", "intensional" or "extensional", etc.), relations, individuals, time, God, actions, events, minds, bodies, etc.

      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.

    2. Epistemology is the study of knowledge and belief: How do we know what there is? How do we know that there is anything? What is knowledge? (Is it justified, true belief, as Plato thought, or are there counterexamples (such as those of Gettier 1963) to that analysis? What is belief?

    3. Logic is the study of good reasoning: What is truth? What is rationality? Which arguments are good ones?

    4. Ethics tries to answer "What is good?", "What ought we to do?".

    5. Ethics is closely related to social and political philosophy, which tries to answer "What are societies?", "What is the nature of law?".

    6. Aesthetics tries to answer "What is beauty?", "What is art?".

    7. Philosophy is one of the few disciplines (history is another) in which the history of itself is one of its branches: The history of philosophy looks at what famous philosophers of the past believed and tries to reinterpret their views in the light of contemporary thinking.

    8. And of central interest for us in the philosophy of computer science course, there are numerous "philosophies of":

      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?)

    Are there any topics that philosophy doesn't touch on?

    (Click on the link to see one philosopher's answer :-)

Copyright © 2007–2011 by William J. Rapaport (rapaport@buffalo.edu)