Parmenides: Stage 1

Issues among Presocratics studied so far: change vs. permanence. Milesians looked for a permanent reality underlying change. They thought that change was real, but could be understood only in terms of something permanent.

Heraclitus found change itself to be the only thing that was permanent. The search for a permanent material substratum is illusory, he thought.

Now comes Parmenides — a turning point in the history of western philosophy - for he denies the reality of change. For Parmenides, change is impossible. The very notion of change is incoherent.

This is not just an assumption that Parmenides makes. Nor is it based on observation. (Quite the contrary: things certainly do appear to change.) Rather, it is the conclusion of a strictly deductive argument, from more basic premises.

And it is not the only startling conclusion Parmenides draws. For he also holds that there is no coming into existence, or ceasing to exist. According to Parmenides, everything that exists is permanent, ungenerated, indestructible, and unchanging.

According to traditional interpretation (no longer universally accepted, but still common) Parmenides goes even further, denying that there is such a thing as plurality. On this view, Parmenides denies that there are many things, maintaining instead that only one thing exists. (It’s not so clear, however, what he thought this one thing is.)

Parmenides is without doubt the most difficult and obscure of the Presocratics. There are numerous different and conflicting interpretations of the curious bits of prose, poetry, and argumentation in the surviving fragments of his work, The Way of Truth. I won’t try to canvas them all. I’ll just sketch out one line that makes some sense of what Parmenides says.

Parmenides was a native of Elea, a Greek city in southern Italy (somewhat south of present day Naples), born about 515-510 B.C. His great work consists of a poem in two main parts. 154 lines of this poem have survived, almost all of which is from the first part. (Experts think that about 90% of the first part has survived.) The two parts of the poem correspond to what Parmenides called “the two ways.”

  1. The Two Ways

    Parmenides distinguishes two “routes” or“ways” or “roads” of inquiry. He then argues against one of these, and in favor of the other. The one he favors he calls The Way of Truth; the other he says is “a path entirely unable to be investigated.” His argument is contained in fragments 2, 3, 6, and 8:

    Come now, I will tell you ... the only routes of inquiry that are for thinking: the one, that it is and that it is not possible for it not to be, is the path of Persuasion (for it attends upon Truth), the other, that it is not and that it is right that it not be, this indeed I declare to you to be a path entirely unable to be investigated: For neither can you know what is not (for it is not to be accomplished) nor can you declare it. [2=B2]

    For the same thing is for thinking and for being. [3=B3]

    It is right both to say and to think that it is what-is; For it can be, but nothing is not. [6=B6]

    Just one story of a route is still left: that it is. [8=B8]

  2. Preliminary questions

    Before we proceed, we must answer the following questions:

    1. When Parmenides says “It is” or “It is not,” what is “it”? What is the subject of these assertions?
    2. What is the sense of “is” here?
    3. What does Parmenides mean when he says “it is right both to say and to think that it is what-is”? (6=B6).

    The most plausible answers are:

    1. Many suggestions have been made (“being,” “what can be known,” “whatever exists,” among others). But the most straightforward and best suggestion is that the subject is any putative object of inquiry. When you inquiry into something, you must make an assumption about the object of your inquiry: either it is, or it is not.

    2. What do these assumptions amount to? We must decide what “is” means here. It is notorious that “is” has a number of different senses. The leading candidates here are the existential and predicative senses.

      But the most plausible, and most popular, way of interpreting Parmenides is with the existential “is”. For “is” in the predicative sense is incomplete. If you say “It is” you haven’t made an assertion. “It is what?” is the appropriate response. But “is” in the existential sense means “exists,” and hence it is complete. “It is” means “it exists,” and this is a complete assertion.

    3. Another, more helpful, translation of this line reads: “That which is there to be spoken and thought of must be. For it is possible for it to be, but not possible for nothing to be.” When Parmenides says that something “is there to be spoken” or “is there to be thought of,” he means that it is (to put it roughly) available for being spoken about, available for thinking. More precisely, he is making a modal claim: that it is possible for it to be spoken of, that it is possible for it to be thought about.  That is, he is making a claim about what the possible objects of reference and the possible objects of thought are.

  3. Deciphering the argument in fragments 2, 3, 6, and 8

    1. The argument as it appears in the text:

      1. There are only two routes (or “roads” or “ways”) of inquiry: (a) “it is,” or (b) “it is not.”
      2. The second way, (1b), is “entirely unable to be investigated.”
      3. For “you may not know that which is not, nor may you declare it.”
      4. For “the same thing is for thinking and for being.”
      5. “That which is there to be spoken and thought of must be. For it is possible for it to be, but not possible for nothing to be.”
      6. “There is still left a single story of a way, that it is.”

    2. On the existential interpretation, a first stab at interpreting the argument looks like this:

      1. If something is inquired into, i.e., thought about, then either: (a) it exists, or (b) it does not exist.
      2. The second alternative is impossible (“entirely unable to be investigated”).

        What follows is an argument against the second alternative (1b):

      3. For it is impossible to think about (“know”) or speak about (“declare”) what does not exist. [= a rejection of (1b)]
      4. For the things that can be thought about are the same as the things that can exist (“is for thinking” means “can be thought about”; “is for being” means “can exist”).
      5. Anything that can exist and can be thought about must exist; for it can exist, and nothing (i.e., what does not exist) cannot exist.
      6. Only the first alternative is possible: if something can be thought about, then it actually exists.

    3. The key to the argument is the move from (4) and (5) to (3). (4) and (5) are clearly premises from which (3) is inferred.

    4. (4) draws a crucial connection between the possibility of existing and the possibility of being thought about:

      It is possible for x to exist iff it is possible for x to be thought about (i.e., iff x is conceivable).

      (5) collapses the distinction between what can exist and what does exist:

      What can exist, does exist. What does not exist, cannot exist.

  4. Summary of results so far

    Parmenides is offering an argument in support of his central thesis:

    (CT) That which is not cannot be thought about or spoken about.

    In this first stage, he presents his argument. In stage 2, he will go on to draw the logical consequences of CT. Note that there are three crucial ideas involved here:

    1. Existence (what actually exists).
    2. Possibility (what can exist).
    3. Conceivability (what can be thought about).

    Parmenides’ two premises link these ideas. One premise (step (4) in the argument) links (b) to (c): what can be thought of = what can exist. The other premise (step (5) in the argument) links (a) to (b): what can exist does exist; what is, must be. Taken together, the two premises link (a) to (c): what can be thought of = what actually exists.

  5. Formal reconstruction of the argument for the central thesis (CT)


    a. A thing can be thought about only if it is possible for it to exist. [= step (4) above]

    b. Anything that does not exist, cannot exist. [= step (5) above]

    But (b) is equivalent to:

    c. Anything that can exist, does exist.

    From (a) and (c) it follows that:

    d. A thing can be thought about only if it exists.

    And (d) is equivalent to:

    e. Anything that does not exist, cannot be thought about. [= (3) above]

    In symbols:

    Tx: x is thought about
    Ex: x exists
    It is possible that: it is possible that …

    a. x (It is possible thatTxIt is possible thatEx) Premise
    b. xEx → ¬It is possible thatEx) Premise
    c. x (It is possible thatExEx) From (b) by contraposition
    d. x (It is possible thatTxEx) From (a) and (c) by hypothetical syllogism
    e. xEx→ ¬It is possible thatTx) From (d) by contraposition

  6. Comments on Parmenides’ conclusion

    Parmenides does not allow that you can think about what does not actually exist but could possibly exist. His argument rules out any distinction between what is and what is not but might be. Parmenides (as Ring says) collapses modal distinctions. For him:

    what is possible = what is actual = what is necessary.

    As Parmenides says (2): “it is and ... it is not possible for it not to be.” What is cannot possibly be otherwise. What can exist does exist, indeed must exist.

    Parmenides is posing constraints on language and on thought, a limit on what can be spoken of or thought about: we cannot speak or think about things that are not (real), that do not exist. That means that much of what goes by the name of “speaking” or “thought” really won’t count as such for Parmenides. If you do anything that Parmenides would call “speaking or thinking of what is not,” Parmenides would not even deign to call it speaking or thinking. For he could argue (along the lines that Plato suggested, cf. Sophist 237C-E):

    If you are speaking of what is not, then what you are speaking about is nothing, i.e., is not anything at all. That is, you are not speaking of anything, which is to say that you are not even speaking. For speaking is always speaking of something, and in the (alleged) case of “speaking of what is not” there is nothing that is being spoken of. So there is no such thing as “speaking of what is not.”

    An exactly similar argument could be used to establish the conclusion that there is no such thing as “thinking of what is not.”

  7. Evaluation of the argument

    It is clearly a formally valid argument. But is it sound? The first premise seems plausible: how could a thing exist if it is not even possible to speak or think about it? And how could one speak or think about something that could not even possibly exist?

    But what of the second premise [(5) in our reconstruction of Parmenides’ argument]? It seems false to say that only what actually, in fact, exists could possibly exist. Why should Parmenides believe this?

    1. Barnes (Presocratics, p. 167) suggests the following: “What doesn’t exist can’t exist” is ambiguous. It might mean either of the following (which are not equivalent):

      1. It is not possible that what does not exist exists.
        x ¬It is possible that(Ex & ¬Ex)

        i.e., for any object, necessarily, if it doesn’t exist, then it doesn’t exist.
        x It is necessary thatEx → ¬Ex)         [‘It is necessary that’ means ‘it is necessary that’.]

      2. If a thing does not exist, then it is not possible for it to exist.
        xEx → ¬It is possible thatEx)

        i.e., for any object, if it doesn’t exist, then its non-existence is a matter of necessity.
        xExIt is necessary that¬Ex)

      (i) is true, indeed a truism. But, as we have seen, the argument requires (ii); and (ii) is false.

    2. This difference can be seen more clearly if we consider a simpler case: the ambiguity of “what exists must exist.” It might mean:

      1. Necessarily, what exists, exists.
        xIt is necessary that (ExEx)
        I.e., for any object, it is necessary that if it exists, it exists. (Necessity of the conditional.)

      2. What exists, exists necessarily.
        x(ExIt is necessary thatEx)
        I.e., for any object, if it exists, then it is a necessarily existing object. (Necessity of the consequent.)

    3. Let us be clear that it is a modal confusion to infer (ii) from (i). We can paraphrase these two different claims as follows:

      1. In every possible world, the things that exist (in that world), exist (in that world).
      2. Whatever (actually) exists, exists in every possible world.

      All (i) tells us that that it is impossible for there to be a world whose population includes things that do not exist in that world. This is (trivially) true. There is no world whose existents do not exist in that world.

      But what (ii) tells us that that it is impossible for there to be a world whose population includes things that do not exist in the actual world. This is a substantive claim, almost surely false, that does not follow from (i). It is by no means obvious that there is no world whose existents do not exist in the actual world. (E.g., your parents might have had one more child than they actually did.)

    4. Another possibility is that Parmenides is not caught in a modal confusion; he is quite self-consciously asserting (ii). His line of reasoning might go like this:

      Suppose something does not exist. How, then, would it be possible for it to exist? Can it come into existence? No, for there is nothing for it to come into existence from. So if it doesn’t now exist, it’s never going to come into existence, and it couldn’t possibly exist.

      This line of reasoning has a certain plausibility, and it would certainly have appealed to Parmenides (cf. fr. 8: “For what birth will you seek for it? How and from where did it grow?”). But it is clearly defective, for two reasons:

      1. For x to be a possible existent, we don’t have to come up with an account of how x might come into existence. E.g., an eternal God might be possible, but we could not explain how such a Being might come into being. God (if God exists) was not born.

      2. Parmenides seems to assume that a thing can come into existence either (a) from being or (b) from not-being. He would rule out (a) on the grounds that a thing can’t come into being from itself; he would rule out (b) on the grounds that nothing comes from nothing.

        But Parmenides has overlooked the possibility that a thing can come into existence from something else. This would be neither from itself, nor from nothing; since it would be from a different being, it would, in a way, be both from a being and from a not-being. It would come into existence from a different being, and from not having itself previously existed. [This is a possibility that Aristotle pursues.]

  8. An alternative account

    There is another possible reason why Parmenides might have believed that it is impossible to talk or think about what does not exist. One might find another argument for the Central Thesis, inspired by B8, lines 34-35:

    “Thinking and the thought that it is are the same. For not without what is, in which it is expressed, will you find thinking.”

    The idea is that thinking just is thinking of something that exists. An argument for CT along these lines might look like this:

    a. S is thinking ↔ S is thinking of something. premise
    b. S is thinking of something ↔ There is something S is thinking of. premise
    c S is thinking of what does not exist ↔ There is nothing S is thinking of premise
    d. There is nothing S is thinking of ↔ S is thinking of nothing. From (b), by contraposition
    e. S is thinking of nothing ↔ S is not thinking. From (a), by contraposition
    f. S is thinking of what does not exist ↔ S is not thinking. From (c), (d), (e), by hypothetical syllogism

    As noted above, this seems to be the way Plato interpreted Parmenides; cf. again Sophist 237C-E, where what is at issue is “saying,” or “talking about,” rather than “thinking.” But the argument Plato supplies works the same way in the case of either speaking or thinking.

    How should one respond to this argument? One response is to say that there is an ambiguity in the notion of “thinking of something.”

    1. In one sense, to say that one is thinking of something is to say that there is an object of thought — an objectively existing thing which has the (additional) feature of being thought about.
    2. In another sense, it is to say that there is a thought content — some proposition or concept being entertained.

    Thus, each of the premises needs to be evaluated in light of this distinction. (a) is plausible only if it concerns thought contents: if you are thinking, there must be a content to your thought; on the “object” reading, (a) begs the question. (b) is plausible only if both antecedent and consequent involve the same sense of “thinking of something.” For (c) to play any role in the argument, however, its consequent must concern thought contents, and its antecedent must concern thought objects: if there is no existing object that S is thinking of, then there is no content to S’s thought. But, so interpreted, (c) is both question-begging and equivocates on the notion of “thinking of something.”

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Copyright © 2003, S. Marc Cohen