I think. I think I am. Therefore I am. I think.

We begin with Eddington:

I find a difficulty in understanding books on philosophy because they talk a great deal about "existence",  and I do not know what they mean.  Existence seems to be a rather important property, because I gather that one of the main sources of division between different schools of philosophy is the question of whether certain things exist or not.  But I cannot even begin to understand these issues, because I can find no explanation of the term "exist".

The word "existence" is, of course, familiar in everyday speech;  but it does not express a uniform idea - a universally agreed principle according to which things can be divided into existing and non-existing.   Difference of opinion as to whether a thing exists or not sometimes arises because the thing itself is imperfectly defined,  or because the exact implications of the definition have not been grasped;  thus the "real existence" of electrons, aether, space, colour, may be affirmed or denied because different persons use these terms with somewhat different implications.  But ambiguity of definition is not always responsible for the difference of view.  Let us take something familiar, say an overdraft at a bank.  No one can fail to understand precisely what that means.  Is an overdraft something which exists?  If the question were put to a vote,  I think some would say that its existence must be accepted as a grim reality,  and others would consider it illogical to concede existence to what is intrinsically a negation.  But what divides the two parties is no more than a question of words.  It would be absurd to divide mankind into two sects,  the one believing in the existence of overdrafts and the other denying their existence.  The division is a question of classification, not of belief.  If you tell me your own answer,  I shall not learn anything new about the nature or properties of an overdraft;  but I shall learn something about your usage of the term "exists"  -  what category of things you intend it to cover.

It is a primitive form of thought that things either exist or do not exist;  and the concept of a category of things possessing existence results from forcing our knowledge into a corresponding frame of thought.  Everyone does this instinctively;  but there are borderline cases in which all do not employ the same criteria,  as an example of the overdraft shows.  A philosopher is not bound by traditional or instinctive conventions to the same extent as a layman; and when he similarly expresses his knowledge in this primitive frame of thought, it is impossible to guess what classificatory system he will adopt.  It would be rather surprising if all philosophers adopted the same system.  In any case I do not see why such a mystery should be made of it,  nor how an arbitrary decision as to the classification to be adopted has come to be transformed into a fervid philosophical belief.

I do not want to make sweeping charges on the basis of a very limited reading of philosophy.  I am aware that in the recondite works the meaning of the term is sometimes discussed.  But, after all, philosophers do occasionally write for the layman;  and some of them seek to repel the scientific invader in language which he is supposed to understand.  What I complain of is that these writers do not seem to realise that the term "exist", if they do not explain the meaning they attach to it, must necessarily be as bewildering to the scientists  as, for example, the term "curvature of space", if left unexplained, would be to the philosopher.  and I think it is not an unfair inference from this omission that they themselves attach more importance to the word than to its meaning.

It is not every sentence containing the verb " to exist" that troubles me,.  The term is often used in an intelligible way.  for me ( and, it appears, also for my dictionary) "exists" is a rather emphatic form of "is".  "A thought eists in somebody's mind," i.e. a thought is in somebody's mind - I can understand that.  " A state of war exists in Ruritania,"  i.e. a state of war is in Ruritania -  not very good English, but intelligible.  but when a philosopher says "Familiar chairs and tables exist", i.e. familiar chairs and tales are....,  I wait for him to conclude.  Yes:  What were you going to say they are?  But he never finishes the sentences/  and I do not know what to make of it.

Speech is often elliptical,  and I do not mind unfinished sentences if I know how they are meant to be finished.  "A horrible noise exists"  presumably is intended to be completed in such form as " A horrible noise is- disturbing me".  But that is not how the philosopher intends me to complete his unfinished statement. "noises actually exist " - and I really have no idea what completion he does intend.  I myself, when I am not intimidated by the existence* of critics determined to make nonsense of my words if it is possible to do so, often say that atoms and electrons exist.  I mean, of course, that they exist - or are - in the physical world,  that being the theme of discussion in the context.  We need not examine the precise ellipsis by which a mathematician says that the root of an equation exists, when he means that the equation has a root;  it is sufficient to say that he has no idea of putting forward a claim to include the root of a mathematical equation in the category of things which philosophers speak of as "really existing".

In the preceding chapters I have discussed a number of things which exist in the physical universe;  that is to say, that are in, or are parts of the physical universe.  We have seen that "to exist in",  even in the equivalent expression " to be part of", is not free from ambiguity,  and is made definite only by the conventions discussed in connection with the concept of analysis.  The question whether the physical universe itself exists has not arisen.  I have, in fact, avoided saying that it exists - which would be an unfinished sentence.  Ordinarily it would be unnecessary to be so particular.  The existence or non-existence of things is a primitive form of thought; and, if I had used the term, it would mean no more than that I was forcing our observational knowledge into such a frame** as it is forced into several other frames that we have discussed.  Knowing, however that as philosophers we must seek to get behind these forms of thought,  I have thought it best in this book to avoid introducing it even temporarily.

* No;  you have not caught me this time.  The critics intimidate me just as much, whether philosophy concedes to them "real existence" or not.

** If we wish the assertion to mean more than the expression of a primitive form of thought, we say "really exists".

Eddington has a point.  Wading through Heidegger's Zein und Seit, one never does quite grasp what "Being" is.  Well, not as a concrete object. Then again, one can read Benedetto Croce's Aesthetic and still have no clear idea what "Beauty" is.  And frankly, the physicist who explains to me patiently and deliberately the tenets of quantum mechanics is just repeating so many words, to me.  Jargon, really.  The physicist insists the concept of quantum mechanics, or even Einsteinian physics, have reality.  I, ultimately, just have to accept that as true.

I've read a very detailed, very technical account of how an internal combustion engine actually manages to produce power.  The explanation went down to the molecular level of the combustion of the fuel, IIRC.  I'm sure it was soundly reasoned and based on the finest understanding of scientific principles and informed engineering.  It still just meant the car starts when the key turns and there's gas in the tank, and all the systems of the automobile function as they were designed to.  It doesn't really make it clearer to me that the engine exists, or that the power it generates has reality.

These are, in other words, enormously slippery concepts.  As I often tell my students, I can't bring abstract concepts like "Justice" or "Beauty" into the classroom so they can identify them the next time they see them.  What is "Justice"?  Where does it come from?  What does it look like?  How do you define it?

Lawyers and politicians have been working on that one for centuries, and so far the closest we've gotten is that we know it when we don't see it.  Could I ever meaningfully say that Justice exists?  And would I mean it in the same way as saying that a platypus exists?

What Eddington is encountering is what Wittgenstein called "language games."  We use words in different ways depending on so many different things:  culture, context, meaning.  And "meaning" is hardly what's confined to the dictionary (which is not the objective arbiter of language after all; dictionaries since Samuel Johnson's day have only recorded the way words are used.  "Awful" for example, once meant "full of awe."  But even if a dictionary insisted that was the only meaning of the word today, we'd consider it a pretty awful definition.).  Wittgenstein argued this confusion arising from such freewheeling use of language as if it were the stuff of reality is what leads to most philosophical conundrums, like:  "How far is up?" or "How long is a piece of string?"

Okay, okay, but seriously, folks.  Take my wife:  please!

I digress....

We can say, for example, that a stone exists.  That's a perfectly sensible English statement which does not seem immediately contradictory or strange, especially if the stone is large and you just stubbed your toe on it.  Clearly it exists apart from your perception of it, or you wouldn't have run your toe against it in the first place (you didn't perceive it until your toe struck it).  But would we also say a stone has existence?  Even if we aren't quite sure just how to define "existence," we'd hesitate to use this sentence, this concept.  Conversely, we can easily say a unicorn does not exist.  Yet it isn't the same thing as saying a unicorn doesn't have existence.

I mean, neither does a stone.

Now it's a bit clearer, to be fair to Heidegger, why Being and existence don't get squarely defined in his philosophy; especially since his philosophy is all about the nature of Being and existence.

What, then, is "existence"?  What do we mean when we say we have existence?  Eddington insists it is "primitive thought" (by which he means to be pejorative.  But "primitive" is almost as acceptable in discourse today as the "n-word" is.  It's a bit too harsh, in other words.  We stumble over it.  Well, I do, anyway.  "Primitive thought" is too simplistic a concept for me, too dismissive. It smacks of arrogance.), but is it really "primitive" (or just simplistic) to think in terms of existence or non-existence, of either/or?

A stone exists, or it doesn't.  And it has existence; or it doesn't.  Now, whether that gets us anywhere worthwhile, whether that tells us anything worth knowing, is worthy of debate.  But it is primitive to examine the issue?  I don't think so.

Do humans have existence?  We're back to Kierkegaard's question; because, if we have it, what is it we have, and how do we prove it?  How do we establish existence?

But what is this unknown against which the understanding in its paradoxical passion collides and which even disturbs man [sic] and his self-knowledge? It is the unknown. But it is not a human being, insofar as he knows man, or anything else that he knows. Therefore, let us call this unknown the god. It is only a name we give to it. It hardly occurs to the understanding to want to demonstrate that this unknown (the god) exists. If, namely the god does not exist, then of course it is impossible to demonstrate it. But if he does exist, then of course it is foolishness to want to demonstrate it, since I, in the very moment the demonstration commences, would presuppose it not as doubtful--which a presupposition cannot be, inasmuch as it is a presupposition--but as decided, because otherwise I would not begin, easily perceiving that the whole thing would be impossible if he did not exist. If, however, I interpret the expression "to demonstrate the existence of the god" to mean that I want to demonstrate that the unknown, which exists, is the god, than I do not express myself very felicitously, for then I demonstrate nothing, least of all an existence, but I develop the definiteness of a concept. 

I start there not because I'm interested in establishing the existence of God; but because S.K. gets us to this question of establishing existence at all, through the arguments about the existence of God.  As the argument goes:  if what you seek to establish as existing doesn't have existence, then it is impossible to establish that it exists (which takes us back to my example of the stone.  But even if the stone exists, are we now willing to say the stone has existence?  If so, what do we mean by that, now?).  If it does exist, then why demonstrate it?  From there the argument slides into the establishment of a concept ("the unknown"), and away form our purposes.  But it is still a good prologue to what follows:

It is generally a difficult matter to want to demonstrate that something exists--worse still, for the brave souls who venture to do it, the difficulty is of such a kind that fame by no means awaits those who are preoccupied with it. The whole process of demonstration continually becomes something entirely different, becomes an expanded concluding development of what I conclude from having presupposed that the object of investigation exists. Therefore in the world of thought, I never reason in conclusion to existence, but I reason in conclusion from existence. For example, I do not demonstrate that a stone exists but that something which exists is a stone. The court of law does not demonstrate that a criminal exists but that the accused, who indeed does exist, is a criminal. Whether one wants to call existence an accessorium or the eternal prius, it can never be demonstrated.

And our stone comes back for us to stumble over again!  It cannot be proven that a stone exists, or, in our example, has existence.  But we can establish that this thing which exists (look!  It's in my hand!  Even now it breaks forth!  Can you not perceive it?!) is a stone.  We can, in other words, identify it.  We can name it.

Never underestimate the power of naming.  Many have pointed out over the centuries it was the first power given to Adam.

But to prove existence, as Kiekegaard says, I continually start with the presupposition of existence.  This is, among other things, the bedrock principle of existentialism, although Sartre used it to turn against essentialism (which is another line of argument entirely).  Our question is this: if we are presupposing existence, what, precisely, are we presupposing?  That this stone in my hand exists because it has mass, weight, breadth, hardness?  Is that all it takes to exist?  Is that what existence comes down to?

Does the mind exist, then?  Eddington speaks approvingly of thoughts existing in the mind.  Does the mind have mass, weight, breadth, hardness?  Does a thought?

And we don't get any closer to a definition if we choose to settle on a single individual as our example:

If one wanted to demonstrate Napoleon's existence from Napoleon's works, would it not be most curious, since his existence certainly explains the works but the works do not demonstrate his existence unless I have already in advance interpreted the word "his" in such a way as to have assumed he exists.

 Kierkegaard points out that existence can never be demonstrated.  But, again, this presupposes a definition of existence which is not itself clearly defined.  We've come quite a long way and gotten no further along.  Or maybe we have.

Existence seems to be a rather important property, because I gather that one of the main sources of division between different schools of philosophy is the question of whether certain things exist or not.  But I cannot even begin to understand these issues, because I can find no explanation of the term "exist".

Actually, the distinction between the Continental and Anglo-American schools of Western philosophy is not over whether "things" exist or not, but over whether existence itself is an important concept worth considering.  Kierkegaard follows the older line, the one that began to fall apart into the two schools we have now when European philosophy tripped over the stone of the Scot David Hume, and the German Immanuel Kant put the pieces back together again.  But before that split took hold and produced the flowering of the two schools, the consensus was pretty much here:  "Whether one wants to call existence an accessorium or the eternal prius, it can never be demonstrated."

Indeed, why should it be?  How could it be?

We are up against the pretty problem of not being able to find what you don't know what to look for.  It's a basic issue in science:  if you don't know to look for it, you'll never find it.  If we don't know how to identify existence, to explain the term we are using, how are we ever going to demonstrate it?

Or are we stuck with Potter Stewart's definition of pornography?

Definitions are important in discussions.  Then again, Socrates should have taught us by now the perils of definition.  Just before his trial he meets the priest Euthyphro, who has brought an action for impiety against his father, whose negligence (and, we would say, cruelty, but we are anachronisms here) has resulted in the death of a slave.  Impressed with Euthyphro's piety, Socrates asks the priest to explain the concept to him, so that he, too (Socrates) will understand.

By the end of the dialogue Euthyphro has abandoned his suit and fled the scene, as the only possible way to escape Socrates' persistent destruction of every definition Euthyphro boldly puts forward.  Kierkegaard identified precisely this kind of "Socratic method" as the "Concept of Irony," and pointed out just how ultimately destructive and nihilistic the pursuit is.  Not, mind, without saying it has a value; just not the value we usually think it has.

So there are perils to insisting that definitions will give us, finally and precisely, clarity.  Definitions will only establish the boundaries of how we use a word and, as Socrates pointed out with poor Euthyphro as his foil (then again, Euthyphro is arrogant and we enjoy seeing his pompous balloon getting punctured), we use words in such contradictory and ultimately conflicting ways, and usually just to justify what we already want to think, or do.

Which sounds terribly cynical; but sometimes such cynicism can be the beginning of wisdom.