De Interpretatione, Chapter 9
Aristotle
Source: J. L. Ackrill, 1963, Aristotle's Categories and De Interpretatione
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The Write-up Note1 is a final-year BA Philosophy essay, pre-submitted in February 2004.



Write-up2 (as at 26/02/2004 20:55:41): Aristotle - Sea Battle

What follows is a pre-submitted BA Finals essay written February 2004 in my last year at Birkbeck. I have left the text untouched.

‘If it is true that there will be a sea-battle tomorrow, it is necessary that there will be a sea-battle tomorrow.’ How does Aristotle escape this consequence?
  1. To answer this question we must address Chapter 9 of Aristotle’s De Interpretatione. In [18a28-18b25], Aristotle gives the argument for fatalism. He follows this up with the consequences of and objections to fatalism3. Finally [19a23-19b4] he gives his solution to the problem, the “traditional” interpretation being that Aristotle denies that future singulars4 have truth-values.
  2. The argument for fatalism
    • The argument proceeds as follows:
      1. The past is unalterable.
      2. Precisely one of the following statements is true:
        • 2.1 There will be a sea-battle tomorrow.
        • 2.2 There will not be a sea-battle tomorrow.
      3. Whichever of 2.1 or 2.2 is true, it was true in the past. Without loss of generality, we’ll assume 2.1.
      4. Because the past is unalterable, we can now do nothing to make false the statement that was true in the past.
      5. Hence, 2.1 is necessarily true, and the future is as unalterable as the past.
    • What support do we have for this interpretation from the text? Aristotle doesn’t explicitly mention the unalterability of the past, but he does make use of arguments involving past truth at two points:
      • “If it is white or is not white, then it was true to say or deny this.” [18b1]
      • “Again, if it is white now it was true to say earlier that it would be white; so that it was always true to say of anything that has happened that it would be so.” [18b9-10]
    • Since the past has happened it was, in retrospect, always true to predict it. The hidden assumption here is that the past is unalterable. If the past could be changed, then a past true statement could be falsified and it would not have been possible to have made necessarily true predictions in the yet more remote past.
      • “It follows that nothing either is or is happening, or will be or will not be, by chance or as chance has it, but everything of necessity.” [18b5-6]
      • “But if it was always true to say that it was so, or would be so, it could not not be so, or not be going to be so … Everything that will be, therefore, happens necessarily.” [18b11-12,15]
    • Deliberation about what to do is obviated because someone might in the past have made a true statement about our future, which would then be fixed [18b31-2]. Actual vocalisation of a truth-claim is not required. It’s enough that someone might or could have said it [18b36-8]. Aristotle’s conclusion [19a1-4] is again that truth-values necessitate states of affairs for the whole of time.
    • The question here is why Aristotle deduces the necessity of the future? For Aristotle, the truth-value of a past true statement is a fact about the past, and there’s nothing we can do to change it, therefore making its claim about the future necessary. Aristotle sees symmetry between the past and the future. If statements about the future have fixed truth-values, then the future that corresponds to them must be fixed, just as if the past is fixed, the truth-values of more remote past predictions are fixed.
    • This covers most of the argument. We might, however, ask whether Aristotle relies on the argument from the fixity of the past, or whether this is merely a supporting consideration. Aristotle on numerous occasions demonstrates the assumption of a correspondence theory of truth – that if a statement is true (or false) the corresponding state of affairs that the statement is about must obtain (or not). This itself seems to imply fatalism on the assumption that future singulars have truth-values. We saw this at [18b11-12], but see also5:
      • “For if it is true to say that it is white or is not white, it is necessary for it to be white or not white.” [18a39-18b1]
      • “For what anyone has truly said would be the case cannot not happen” [19a4-5]
    • The causative direction is from fact to truth, and not vice-versa:
      • “So, since statements are true according to how the actual things are.” [19a32]
    • The question is whether these passages introduce a modal fallacy (p → ☐p). While this depends on what strength Aristotle gives here to “necessary”, the argument from the fixity of the past means that Aristotle need not rely on the brute assumption of a correspondence theory.
  3. Objections to fatalism
    • Aristotle, along with most of us, thinks that the future is open: chance and deliberation play a part in what the future will be. Deliberation, and not just action, brings things about [19a7-10]. What has not yet happened has the possibility of happening or not happening. Aristotle’s example is of a cloak [19a11-15] that is expected to wear out, but may be prevented from so doing by being cut up first. Because deliberation is useful and the future is open Aristotle argues that it’s obvious that there’s something wrong with the fatalist’s case.
  4. Aristotle’s Solution
    • Since Aristotle seems to support the logic of the fatalist’s argument, why does he reject its conclusion? Aristotle denies premise (2) of the argument. To see this, we need to return to the first paragraph of Chapter 9:
      • “[18a28] With regard to what is and what has been it is necessary for the affirmation or the negation to be true or false. [18a29] And with universals taken universally it is always necessary for one to be true and the other false, [18a31] and with particulars too, as we have said; [18a32] but with universals not spoken of universally it is not necessary. [18a33] But with particulars that are going to be it is different.”
    • Future singulars are going to be “different”, but to what? The opening paragraph is dealing with the truth-values of contradictory pairs of statements. At this point we need to introduce what Whitaker [1996] calls the RCP (Rule of Contradictory Pairs): that precisely one of a pair of contradictory statements – such as our premise (2) – is true and the other false.
    • Ackrill [1963] takes [18a29-32] to be an expansion of [18a28], thereby giving [18a29] a different meaning to [18a28], of which it covers only a part (ie. excluding “universals not spoken of universally”). Consequently, [18a28] should be read as “… necessary that the affirmation (and equally that the negation) should be either true or false” – that is, that each of a contradictory pair of statements must have a definite truth-value of truth or falsehood. [18a29], however, says additionally that one statement is true and the other false. Universals not spoken of universally are exceptional because both contradictories can be true, as Aristotle had previously shown in Chapter 7, [17b29-33].
    • Whitaker takes [18a28] itself to be a statement of RCP, elliptical for “… it is necessary either for the affirmation to be true and the negation false, or for the affirmation to be false and the negation true”. This seems better to explain why Aristotle has “… affirmation or the negation ...”, rather than “ ... and …”, but otherwise explains [18a29-32] less comfortably.
    • However, in the course of the argument, Aristotle rejects the possibilities that both contradictories can be true ([18a38]) and that both can be false ([18b17]), so it doesn’t matter which of the two alternative formulations we choose. Aristotle argues that contradictory pairs of future singulars fail to satisfy either PB (Principle of Bivalence) – the claim that every proposition is either true or false – or RCP – the claim that one is true and the other false.
    • The Chapter concludes with the rejection of RCP:
      • “Clearly, then, it is not necessary that of every affirmation and opposite negation one should be true and the other false.” [19a39-19b2]
    • That Aristotle sees RCP-violation as the problem is evident in:
      • “These and others like them are the absurdities that follow if it is necessary, for every affirmation and negation … that one of the opposites be true and the other false.” [18b26-29]
    • Consequently, we see that part of Aristotle’s solution is the claim that, while for a contradictory pair of singulars about the present or the past, one must be true and the other false, this doesn’t hold for similar statements about the future. With what does Aristotle replace the RCP? For Aristotle, actual things necessarily are. But they are only necessary once (or when) they happen:
      • “… to say that everything that is, is of necessity, when it is, is not the same as saying unconditionally that it is of necessity.” [19a25-26]
    • … and for chance events:
      • “… it is necessary for one or the other of the contradictories to be true or false – not, however, this one or that one, but as chance has it; or for one to be true rather than the other, yet not already true or false.” [19a36-8]
    • Aristotle concludes that contradictory pairs of statements initially lack, but later acquire, truth-values.
  5. Responses to Aristotle
    • Does Aristotle need to conclude this? If we think not, we must either fault the fatalist argument (which Aristotle himself seems to accept, though he rejects its initial premise) or give another response.
    • There is a tempting response to fatalism that is incorrect, but instructive. We can view the situation in possible-worlds terminology, a vocabulary admittedly foreign to Aristotle. Just as in counterfactual situations, we consider possible worlds in which statements about the past that are true in the actual world are false, so we can think of possible worlds in which statements about the future that are true in the actual world are false. From this we can see that a true statement about the future is not necessarily true – there are possible worlds in which it is false; just as there are possible worlds in which true statements about the past are false. There is symmetry between past and future, but this doesn’t imply fatalism.
    • However, this response is mistaken. The fatalist’s claim is that now the past is unalterable and he has an argument that if this is so, then the future must be unalterable in just the same way: the future is necessary in the same way as the past. This is compatible with there being other possible worlds in which different things happen in the past, just as there are those in which different things happen in the future. Facts about the past are not logically necessary.
    • Aristotle himself recognises this. He mentions necessity 31 times in this Chapter, without being careful to distinguish its various forms. His basic understanding of necessity is given in [18b13-14]. Something is necessary if it is impossible for it not to occur.
    • Ackrill [1963] distinguishes three forms:
      1. Logical necessity. A proposition may be analytic or the conclusion of a valid argument, cases that are themselves important to distinguish.
      2. Causal necessity. The necessity resulting from the operation of the laws of nature. This form of necessity is not explicitly mentioned in this Chapter.
      3. Temporal necessity. The unalterability of the past.
    • Aristotle distinguishes “unconditionally necessity6” – probably causal – from temporal necessity:
      • “What is, necessarily is, when it is; and what is not, necessarily is not, when it is not. But not everything that is, necessarily is; and not everything that is not, necessarily is not. For to say that everything that is, is of necessity, when it is, is not the same as saying unconditionally that it is of necessity.” [19a23-5]
    • Ayer and Lewis flatly reject Aristotle’s solution of propositions acquiring truth-values. Both accept the timelessness of truth:
      • “…if something is so, it is so independently of the date at which it occurs. This is an application of the logical truism that if p, then p, no matter what proposition p may be7.”
    • Sorabji [1975] raises issues with this response, and suggests another possibility, which Ayer and Lewis also support. He argues that I can affect the past in cases such as that whereby I can make my previous birthday my last by committing suicide. I make the past statement “this is my last birthday” true by making the facts correspond to it. Truth, like “last”, is a relational term. We can make things – past statements – have been true. Sorabji thinks this, rather than showing the absence of power to do other than the past statement prophesies, merely shows the absence of its exercise. So, of a past true statement about the now future, we have the power both to make it have been true, but also the unexercised power to make it have been false.
    • We can, in certain circumstances, have backward causation. Present actions cannot cause past events, but present actions can make past statements true. My present action makes its past prediction true, rather than the truth of the past prediction necessitating my present action. If we accept the timelessness of truth, then this prediction was always true, so in what sense am I free not to perform the act? The answer is that I’m free in every way that we normally think of as freedom. I have the wherewithal to do it and am uncoerced. I just act; and it’s this that makes the past statement true.
    • Both Ayer and Lewis accept the symmetry between the past and the future, but deny the adverse consequences that Aristotle sees. Lewis argues that neither the past nor the future can be “changed”:
      • “You cannot change a present or future event from what it was originally to what it is after you change it. What you can do is change the present or the future from the unactualised way they would have been without some action of yours to the way they actually are8”.
    • According to Lewis, if you do think of unalterability as a kind of necessity, you mustn’t think that this conflicts with freedom or contingency. In one sense, the future is unalterable, and so necessary, as is the past, but that doesn’t mean that what we do now makes no difference to the future, or the past. We can causally affect both the future and the past, but we can’t affect it if this would make it contrary to what it is.
    • Of course, if causal determinism is true, there is only one physically realisable world, given its initial conditions. In that case, the future would be physically closed, even though logically open. However, any discussion of causation is completely absent from Aristotle’s fatalist argument. He is thinking only of logical and temporal, not causal necessity.
  6. Conclusion
    • Aristotle escapes the conclusion that the truth of the statement that there will be a sea-battle tomorrow necessitates there being a sea-battle tomorrow by denying that it makes sense to claim either that there will be or will not be a sea-battle tomorrow. As yet, neither of these statements is true or false. However, Aristotle need not have made this concession, but could have argued that true predictions are made true by the contingent future events they predict.
  7. Bibliography



In-Page Footnotes

Footnote 2: Footnote 3: [18b26-19a6] and [19a7-22].

Footnote 4: Assertions (or denials) about a particular future event, such as the sea-battle in our question.

Footnote 5: And [18a35], [18b3] & [18b22].

Footnote 6: 2016: presumably this ought to read “unconditional necessity”.

Footnote 7: Ayer [1973, p.238].

Footnote 8: [1976, p.150].


Text Colour Conventions (see disclaimer)

  1. Blue: Text by me; © Theo Todman, 2017



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