Aristotle on Truth available in Hardcover
- ISBN-10:
- 0521823285
- ISBN-13:
- 9780521823289
- Pub. Date:
- 09/30/2004
- Publisher:
- Cambridge University Press
- ISBN-10:
- 0521823285
- ISBN-13:
- 9780521823289
- Pub. Date:
- 09/30/2004
- Publisher:
- Cambridge University Press
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Product Details
| ISBN-13: | 9780521823289 |
|---|---|
| Publisher: | Cambridge University Press |
| Publication date: | 09/30/2004 |
| Pages: | 354 |
| Product dimensions: | 5.98(w) x 9.02(h) x 0.94(d) |
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Cambridge University Press
0521823285 - Aristotle on Truth - by Paolo Crivelli
Excerpt
Introduction
The study of truth is a central part of the philosophical tradition we have inherited from classical Greece. Aristotle played an important role in developing and sharpening the debate in this area and on many issues that are connected with it. I have two primary goals: to offer a precise reconstruction of all of Aristotle's most significant views on truth and falsehood and to gain a philosophical understanding of them. In this introduction I first offer an overview of Aristotle's theory of truth and then discuss the methodology I adopt in pursuing my primary goals.
I AN OVERVIEW OF ARISTOTLE'S THEORY OF TRUTH
Why an overview? Aristotle speaks about truth and falsehood in passages from several works, mainly the Categories (chapters 4, 5, 10, and 12), de Interpretatione (chapters 1-9), Sophistici Elenchi (chapter 25), de Anima (chapter 3.6), and the Metaphysics (chapters Γ 7, Δ 7, Δ 29, Ε 4, and Θ 10). Truth and falsehood are not the main topic of these works: their discussions of truth and falsehood are asides. Reconstructing an Aristotelian theory of truth and falsehood on the basis of such asides poses complicated problems of various sorts. To help readers to keep their orientation through the many bifurcations of the arguments addressing these problems, I decided to offer a concise but precise map of the territory - an overview of Aristotle's theory of truth. References to the passages from Aristotle's works that substantiate the attribution of a certain view to him, and an examination of the relevant secondary literature, will be found in the chapters that follow this introduction.
Universals. To expound Aristotle's theory of truth, I need to present some of his views on universals and signification. I begin with universals.
Luckily, it is not necessary to embark on the daunting task of a complete exposition of Aristotle's views on universals. Aristotle is to this extent a realist about universals: in his view, universals are objects whose nature is neither mental nor linguistic (they are neither concepts nor linguistic expressions). He believes that every universal exists when and only when1 it holds of some individual or other that at some time or other exists.2
Let me spend a few words explaining why the phrase 'at some time or other' is needed. According to Aristotle, some universals sometimes hold of individuals that do not exist then, but exist at other times. For example, Aristotle seems to think that at any time the universal poet3 holds of all and only those individual human beings (including those who at that time do not exist) who by that time have authored some poem. In particular, Aristotle would probably grant that although Homer does not exist now, the universal poet holds now of Homer. It is because of universals of this sort that the phrase 'at some time or other' is needed.
Aristotle is likely to believe that every universal is everlasting, i.e. exists always. Hence he is likely to be committed to the view that every universal at all times holds of some individual or other that at some time or other exists - in short, that all universals are always instantiated. This of course leaves the possibility open that every individual that at some time or other exists and of which a certain universal holds at one time could be other than every individual that at some time or other exists and of which the same universal holds at a certain other time - in short, the possibility remains that some universal could be instantiated by different individuals at different times.
Signification. I now move on to expound some of Aristotle's views on signification. Aristotle thinks that some utterances of certain noun-phrases and certain adjectival phrases signify a single universal: e.g. he would grant that some utterances of 'man' signify the universal man and that some utterances of 'white' signify the universal white. He also thinks that some utterances of certain noun-phrases signify a single individual: e.g. he would grant that some utterances of 'Socrates' signify Socrates, the Athenian philosopher executed in 399 BC. However, he believes that some utterances of certain noun-phrases and some of certain adjectival phrases signify neither a single universal nor a single individual: e.g. he would concede that some utterances of 'walking white man' or 'walking, white, and tall' signify neither a single universal nor a single individual (he would claim that each of these utterances signifies many universals which do not coalesce in a single universal).
What can be true or false? Having presented Aristotle's views on universals and signification that are necessary to understand his theory of truth, I am in a position to begin addressing the main themes of the latter. Let me start with Aristotle's conception of the bearers of truth or falsehood.
According to Aristotle, items that are true or false are of three main kinds: sentences, thoughts, and certain objects whose nature is neither mental nor linguistic. The sentences that are true or false are sentence-tokens, utterances, events of speech that occur over relatively short portions of time. Similarly, the thoughts that are true or false are thought-tokens, either mental events that occur over relatively short portions of time or thinker-individuated mental states.
For Aristotle, events of perceiving and imagining also are true or false. Events of perceiving and imagining fall under none of the three kinds I just mentioned: they are neither thoughts, nor sentences, nor objects whose nature is neither mental nor linguistic. Since Aristotle's views on the truth and falsehood of events of perceiving and imagining are somewhat isolated from the rest of his reflection on truth and falsehood, in this introduction I shall say nothing more about them.
A puzzling view. A particularly puzzling part of Aristotle's theory of truth is his view that among items that are true or false there are objects (I sometimes use 'object' to mean 'object whose nature is neither mental nor linguistic': I trust that the context will make it clear whether a given occurrence of 'object' is to be understood in this narrow sense). On this point Aristotle's theory of truth is radically different from some modern ones: modern philosophers are ready to acknowledge that certain thoughts or sentences are true or false, but some of them would jib at the suggestion that some objects are true or false.
These objects that are true or false occupy a central position in Aristotle's theory of truth. What are they? What roles do they play in Aristotle's theory of truth?
What are the objects that are true or false? Aristotle distinguishes two kinds of objects that are true or false: composite objects and simple objects.
Some composite objects that are true or false are states of affairs.4 A state of affairs, which is an object, is composed of two further objects: one of the objects of which it is composed is a universal, the other is either a universal or an individual. A state of affairs is true when and only when the objects of which it is composed are reciprocally combined in the relevant way; it is false when and only when the objects of which it is composed are reciprocally divided in the relevant way.5 For example, the state of affairs that Socrates is seated is composed of the universal seated and of the individual Socrates; it is true when and only when the universal seated is combined in the relevant way with Socrates, i.e. when and only when Socrates is seated; it is false when and only when the universal seated is divided in the relevant way from Socrates, i.e. when and only when Socrates is not seated. Again, the state of affairs that every diagonal is commensurable is composed of the universal commensurable and of the universal diagonal; it is true when and only when the universal commensurable is combined in the relevant way with the universal diagonal, i.e. when and only when every diagonal is commensurable; it is false when and only when the universal commensurable is divided in the relevant way from the universal diagonal, i.e. when and only when some diagonal is not commensurable. Since no diagonal ever is commensurable, the state of affairs that the diagonal is commensurable is never true but always false. Aristotle allows only 'affirmative' states of affairs: among states of affairs there are the state of affairs that Socrates is seated and the state of affairs that every diagonal is commensurable, but there is not a state of affairs that Socrates is not seated nor is there one that not every diagonal is commensurable. In principle, a state of affairs can exist at a time when it is false, i.e. at a time when the objects of which it is composed are reciprocally divided in the relevant way. For example, the state of affairs that Socrates is seated exists at certain times when it is false; again, the state of affairs that every diagonal is commensurable always exists and is always false. The combination that makes a state of affairs true is not to be confused with the composition whereby the state of affairs is composed of further objects. By the same token, the division that makes a state of affairs false does not destroy the composition whereby the state of affairs is composed of further objects (otherwise the state of affairs could not, even in principle, exist at any time when it is false). For example, the state of affairs that Socrates is seated remains composed of the universal seated and of the individual Socrates even when the universal seated is divided from the individual Socrates in such a way as to make the state of affairs in question false. It remains unclear whether in Aristotle's view all states of affairs are everlasting: does Aristotle believe that the state of affairs that Socrates is seated exists both before and after Socrates exists? A state of affairs, as it is conceived of by Aristotle, is best understood as an object corresponding to a complete present-tense affirmative predicative assertion, and as being composed of the objects signified by the assertion's predicate and subject. For example, the state of affairs that Socrates is seated corresponds to the whole present-tense affirmative predicative assertion that is an utterance of 'Socrates is seated', and is composed of the universal seated, which is signified by the assertion's predicate (an utterance of 'seated'), and of the individual Socrates, who is signified by the assertion's subject (an utterance of 'Socrates').
As I said, some composite objects that are true or false are states of affairs. According to Aristotle, material substances (e.g. Socrates and the horse Bucephalus) are composite objects in that they consist of form and matter. Material substances are not states of affairs, but they resemble states of affairs in interesting respects: as for a state of affairs to be true is to be combined, so for a material substance to exist is to be combined, i.e. it is for its form to be combined with its matter; as for a state of affairs to be false is to be divided, so for a material substance not to exist is to be divided, i.e. it is for its form to be divided from its matter. Aristotle perhaps thinks that material substances rank among the composite objects that are true or false, that for a material substance to be true is to exist, and that for a material substance to be false is not to exist. I can use only the cautious expression 'Aristotle perhaps thinks . . .' because the evidence for attributing the position in question to Aristotle is far less than clear cut. However, independently of whether Aristotle does endorse the position in question, at least two differences between states of affairs and material substances are worth noting. First, while some state of affairs exists at times when it is false, no material substance exists at times when it is false (because, according to the position in question, for a material substance to be false is not to exist). Second, although some material substances (i.e. celestial bodies) are everlasting, most are not; on the other hand, Aristotle does not state how long states of affairs exist, but his position might well be that all states of affairs are everlasting.
Since a simple object has no components between which combination or division could obtain, for a simple object to be true cannot be to be combined, nor can for it to be false be to be divided. Rather, for a simple object to be true is simply to exist, and for it to be false is simply not to exist. Aristotle distinguishes two kinds of simple objects: essences and incorporeal substances. Essences are natural kinds (e.g. the kind horse).6 The remaining simple objects, incorporeal substances, are God and (perhaps) the intellects that move the heavenly spheres.7 The application of 'true' to incorporeal substances should not arouse wonder: 'true' is one of the epithets traditionally used to speak of God. Both essences and incorporeal substances are everlasting, i.e. exist always. Hence, all simple objects exist always.
The sense of 'true' and 'false' whereby they apply to objects is probably Aristotle's own creation: it is an extension of the ordinary sense of these expressions which Aristotle introduces in order to construct a better theory of truth. It is not, however, completely unconnected with ordinary usage: 'true' can be used (both in Greek and in English) to mean 'real' (as in 'true coin'), and 'real' is connected with 'existent' (although 'real' and 'existent' are used differently, one can employ the phrase 'the contrast between dreams and what is real' to describe the discrepancy between what exists and what someone would like to exist).
Aristotle's views on the nature of the bearers of truth or falsehood can now be conveniently summarised by the following schema:
What roles do the objects that are true or false play in Aristotle's theory of truth? Objects that are true or false play three roles in Aristotle's theory of truth: first, they contribute to explaining what it is to be true or false for items of other kinds which can be such, i.e. for thoughts and sentences; second, they are bearers of modal attributes; third, they are targets of propositional attitudes. In the following subsections I shall examine these three roles in turn.
The first role of objects that are true or false: contributing to explaining what it is to be true or false for thoughts and sentences. As I just said, the first role played in Aristotle's theory of truth by objects that are true or false is to contribute to explaining what it is to be true or false for thoughts and sentences. This role recalls a strategy which is often adopted in modern philosophy of logic, from Frege onwards: that of explaining the truth and falsehood of certain mental states and certain sentences by appealing to the truth and falsehood of propositions (abstract entities whose nature is neither mental nor linguistic). Although there are important differences between Aristotle's conception and the modern strategy, at this stage I would like to call attention to the resemblance.
To expound how objects that are true or false contribute to explaining what it is to be true or false for thoughts and sentences, I must say something about Aristotle's views on thoughts and sentences that are true or false.
Truth-evaluable sentences. Not every sentence is either true or false: some are neither (e.g. prayers). Every sentence that is true or false is an assertoric sentence, or (as Aristotle often calls it) an assertion. But the converse fails: some assertions are neither true nor false (read on to find out which). Assertions coincide with truth-evaluable sentences, i.e. with the sentences with regard to which the question 'Is it true or false?' can be reasonably asked. Note that this question cannot be reasonably asked with regard to certain sentences (e.g. prayers). In the case of some sentences with regard to which the question 'Is it true or false?' can be reasonably asked, the correct answer is 'Neither'. An analogy helps to clarify. Physical objects coincide with colour-evaluable objects, i.e. with the objects with regard to which the question 'What colour is it?' can be reasonably asked. Note that this question cannot be reasonably asked with regard to certain objects (e.g. numbers). In the case of some objects with regard to which the question 'What colour is it?' can be reasonably asked, the correct answer is 'None' (e.g. some transparent objects like crystal balls or diamonds).
Assertions are utterances, i.e. expression-tokens (not expression-types), events of speech that occur over relatively short portions of time.
Truth-evaluable thoughts. Aristotle does not explicitly isolate a class of truth-evaluable thoughts that constitute the mental counterparts of assertions. However, since he regards the spheres of thought and speech as closely analogous, indeed, almost as isomorphic, he is likely to believe that there is such a class of truth-evaluable thoughts corresponding to the class of truth-evaluable sentences, i.e. to the class of assertions.
Some of Aristotle's remarks indicate that he would agree that every belief is a truth-evaluable thought, i.e. a thought with regard to which the question 'Is it true or false?' can be reasonably asked. However, I doubt that Aristotle would claim that every truth-evaluable thought is a belief. Hence, for Aristotle beliefs probably constitute a proper subclass of truth-evaluable thoughts. I guess Aristotle would grant that not every belief is either true or false.
Simple and composite assertions. Aristotle distinguishes two kinds of assertions: simple assertions and composite assertions. An assertion is simple just in case it concerns exactly one object; it is composite just in case it concerns more than one object. Every simple assertion is either affirmative or negative. Composite assertions are equivalent to utterances constructed from several assertions linked by connective particles.
Aristotle concentrates on simple assertions, i.e. assertions that concern exactly one object. He has little to say about composite assertions: he acknowledges their existence, but they remain at the margins of his reflection. He never states that some sentences that are true or false have no assertoric force (like the utterance of 'Socrates is seated' which is a part of an utterance of 'Either Socrates is seated or Socrates is not seated'). Nor does he discuss utterances of 'Either Socrates is seated or Socrates is seated': are they simple (because they concern exactly one object, i.e. the state of affairs that Socrates is seated) or composite (because they are disjunctive)?
Simple beliefs. Aristotle does not explicitly isolate a class of simple beliefs that are the mental counterparts of simple assertions. However, since (as I said) he regards the spheres of thought and speech as closely analogous, he is likely to take such a class for granted: he probably thinks that simple beliefs are those beliefs that concern exactly one object, and that every simple belief is either affirmative or negative.
A general definition of truth and falsehood for simple beliefs and assertions. Having expounded Aristotle's views on thoughts and sentences that are true or false, I am now in a position to address his conception of how objects that are true or false contribute to explaining what it is to be true or false for thoughts and sentences. Objects play this role, in particular, with regard to simple beliefs and simple assertions.
Aristotle's theory of truth and falsehood for simple beliefs and assertions is governed by a general definition of truth and falsehood (henceforth 'DTF'):
| DTF | Every simple belief, or assertion, concerns exactly one object and is either affirmative or negative. Every affirmative simple belief, or assertion, posits that the object it concerns is true. Accordingly, an affirmative simple belief, or assertion, is true when and only when the object it concerns is true; an affirmative simple belief, or assertion, is false when and only when the object it concerns is false. Every negative simple belief, or assertion, posits that the object it concerns is false. Accordingly, a negative simple belief, or assertion, is true when and only when the object it concerns is false; a negative simple belief, or assertion, is false when and only when the object it concerns is true. |
DTF is a definition of truth (at least for simple beliefs and assertions). Aristotle does not address the issue of the criterion of truth (roughly, the issue of establishing what, if any, reliable ways humans have of discovering truths). Aristotle's silence on the issue of the criterion of truth is remarkable in view of the fact that shortly after his death, with the advent of the Hellenistic philosophical schools of the third and second centuries BC, this issue becomes a hot topic of philosophical debate.
DTF covers at one blow all simple beliefs and assertions, those concerning composite objects as well as those concerning simple ones. It is worthwhile working out the details of Aristotle's account for each case. So, let us examine the forms taken on by DTF with simple beliefs and assertions concerning composite objects and with simple beliefs and assertions concerning simple objects. However, there are two kinds of composite objects: states of affairs and material substances. Let us then study the forms of DTF with regard to simple beliefs and assertions concerning (i) those composite objects that are states of affairs, (ⅱ) those composite objects that are material substances, and (ⅲ) simple objects.
Predicative assertions and beliefs. The simple assertions which concern those composite objects that are states of affairs are predicative assertions; similarly, the simple beliefs that concern those composite objects that are states of affairs are predicative beliefs. Let me first spend a few paragraphs explaining Aristotle's views on predicative assertions and predicative beliefs.
Predicative assertions display a subject-predicate structure (this can be clearly seen in examples of predicative assertions like utterances of the sentence-type 'Socrates is seated' or of the sentence-type 'Socrates is not seated'). Every predicative assertion has at least three parts: the predicate, the subject, and the copula. In every predicative assertion, the predicate signifies a universal, the subject signifies either a universal or an individual, and the copula combines with the predicate to form a predicative expression. Consider a predicative assertion that is an utterance of 'Socrates is seated': the predicate is the part of the assertion that is an utterance of the adjective 'seated' and signifies the universal seated; the subject is the part of the assertion that is an utterance of the name 'Socrates' and signifies the individual Socrates; and the copula is the part of the assertion that is an utterance of 'is' and combines with the predicate to form the predicative expression that is an utterance of 'is seated'. Every predicative assertion is either affirmative (e.g. an utterance of 'Socrates is seated') or negative (e.g. an utterance of 'Socrates is not seated'). Many predicative assertions have further parts over and above the predicate, the subject, and the copula: they contain utterances either of a negative particle (an utterance of 'not', as in an utterance of 'Socrates is not seated') or of a quantifying expression (an utterance of 'every', 'no', 'some', or 'not every', as in an utterance of 'No horse is white'). Many assertions that contain no copula are regarded by Aristotle as equivalent to assertions that do contain one: e.g. for Aristotle an utterance of 'Socrates walks' is equivalent to one of 'Socrates is walking'. Note that in English 'Socrates is walking' is not equivalent to 'Socrates walks'. Aristotle's view, however, is correct with respect to Greek usage: the Greek sentence-type rendered by 'Socrates is walking' is in fact equivalent to that rendered by 'Socrates walks'.
A predicative belief is a belief whose literal linguistic expression would be a predicative assertion. For example, Plato's belief that Socrates is seated is a predicative belief because its literal linguistic expression would be a predicative assertion that is an utterance of 'Socrates is seated'. Every predicative belief has a part that constitutes its predicate (it is about, or concerns, or - as I shall often say - grasps a universal) and one that constitutes its subject (it grasps either a universal or an individual). For example, in Plato's belief that Socrates is seated, the predicate is the part of the belief that grasps the universal seated, the subject is the part that grasps the individual Socrates. Every predicative belief is either affirmative (e.g. Plato's belief that Socrates is seated) or negative (e.g. Simmias' belief that Socrates is not seated). Note that the predicate and the subject of a predicative assertion are utterances, and they signify objects; the predicate and the subject of a predicative belief are thoughts, and they grasp objects.
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