See CYRENAICS. Aristotle (384–322 B.C.), preeminent Greek philosopher born in Stagira, hence sometimes called the Stagirite. Aristotle came to Athens as a teenager and remained for two decades in Plato’s Academy. Following Plato’s death in 347, Aristotle traveled to Assos and to Lesbos, where he associated with Theophrastus and collected a wealth of biological data, and later to Macedonia, where he tutored Alexander the Great. In 335 he returned to Athens and founded his own philosophical school in the Lyceum. The site’s colonnaded walk (peripatos) conferred on Aristotle and his group the name ‘the Peripatetics’. Alexander’s death in 323 unleashed anti- Macedonian forces in Athens. Charged with impiety, and mindful of the fate of Socrates, Aristotle withdrew to Chalcis, where he died. Chiefly influenced by his association with Plato, Aristotle also makes wide use of the pre- Socratics. A number of works begin by criticizing and, ultimately, building on their views. The direction of Plato’s influence is debated. Some scholars see Aristotle’s career as a measured retreat from his teacher’s doctrines. For others he began as a confirmed anti-Platonist but returned to the fold as he matured. More likely, Aristotle early on developed a keenly independent voice that expressed enduring puzzlement over such Platonic doctrines as the separate existence of Ideas and the construction of physical reality from two-dimensional triangles. Such unease was no doubt heightened by Aristotle’s appreciation for the evidential value of observation as well as by his conviction that long-received and well-entrenched opinion is likely to contain at least part of the truth. Aristotle reportedly wrote a few popular works for publication, some of which are dialogues. Of these we have only fragments and reports. Notably lost are also his lectures on the good and on the Ideas. Ancient cataloguers also list under Aristotle’s name some 158 constitutions of Greek states. Of these, only the Constitution of Athens has survived, on a papyrus discovered in 1890. What remains is an enormous body of writing on virtually every topic of philosophical significance. Much of it consists of detailed lecture notes, working drafts, and accounts of his lectures written by others. Although efforts may have been under way in Aristotle’s lifetime, Andronicus of Rhodes, in the first century B.C., is credited with giving the Aristotelian corpus its present organization. Virtually no extant manuscripts predate the ninth century . ., so the corpus has been transmitted by a complex history of manuscript transcription. In 1831 the Berlin Academy published the first critical edition of Aristotle’s work. Scholars still cite Aristotle by page, column, and line of this edition.
Logic and language. The writings on logic and language are concentrated in six early works: Categories, On Interpretation, Prior Analytics, Posterior Analytics, Topics, and Sophistical Refutations. Known since late antiquity as the Organon, these works share a concern with what is now called semantics. The Categories focuses on the relation between uncombined terms, such as ‘white’ or ‘man’, and the items they signify; On Interpretation offers an account of how terms combine to yield simple statements; Prior Analytics provides a systematic account of how three terms must be distributed in two categorical statements so as to yield logically a third such statement; Posterior Analytics specifies the conditions that categorical statements must meet to play a role in scientific explanation. The Topics, sometimes said to include Sophistical Refutations, is a handbook of ‘topics’ and techniques for dialectical arguments concerning, principally, the four predicables: accident (what may or may not belong to a subject, as sitting belongs to Socrates); definition (what signifies a subject’s essence, as rational animal is the essence of man); proprium (what is not in the essence of a subject but is unique to or counterpredicable of it, as all and only persons are risible); and genus (what is in the essence of subjects differing in species, as animal is in the essence of both men and oxen).
Categories treats the basic kinds of things that exist and their interrelations. Every uncombined term, says Aristotle, signifies essentially something in one of ten categories – a substance, a quantity, a quality, a relative, a place, a time, a position, a having, a doing, or a being affected. This doctrine underlies Aristotle’s admonition that there are as many proper or per se senses of ‘being’ as there are categories. In order to isolate the things that exist primarily, namely, primary substances, from all other things and to give an account of their nature, two asymmetric relations of ontological dependence are employed. First, substance (ousia) is distinguished from the accidental categories by the fact that every accident is present in a substance and, therefore, cannot exist without a substance in which to inhere. Second, the category of substance itself is divided into ordinary individuals or primary substances, such as Socrates, and secondary substances, such as the species man and the genus animal. Secondary substances are said of primary substances and indicate what kind of thing the subject is. A mark of this is that both the name and the definition of the secondary substance can be predicated of the primary substance, as both man and rational animal can be predicated of Socrates. Universals in non-substance categories are also said of subjects, as color is said of white. Therefore, directly or indirectly, everything else is either present in or said of primary substances and without them nothing would exist. And because they are neither present in a subject nor said of a subject, primary substances depend on nothing else for their existence. So, in the Categories, the ordinary individual is ontologically basic. On Interpretation offers an account of those meaningful expressions that are true or false, namely, statements or assertions. Following Plato’s Sophist, a simple statement is composed of the semantically heterogeneous parts, name (onoma) and verb (rhema). In ‘Socrates runs’ the name has the strictly referential function of signifying the subject of attribution. The verb, on the other hand, is essentially predicative, signifying something holding of the subject. Verbs also indicate when something is asserted to hold and so make precise the statement’s truth conditions. Simple statements also include general categorical statements. Since medieval times it has become customary to refer to the basic categoricals by letters: (A) Every man is white, (E) No man is white, (I) Some man is white, and (O) Not every man is white. On Interpretation outlines their logical relations in what is now called the square of opposition: A & E are contraries, A & O and E & I are contradictories, and A & I and E & O are superimplications. That A implies I reflects the no longer current view that all affirmative statements carry existential import.
One ambition of On Interpretation is a theory of the truth conditions for all statements that affirm or deny one thing or another. However, statements involving future contingencies pose a special problem. Consider Aristotle’s notorious sea battle. Either it will or it will not happen tomorrow. If the first, then the statement ‘There will be a sea battle tomorrow’ is now true. Hence, it is now fixed that the sea battle occur tomorrow. If the second, then it is now fixed that the sea battle not occur tomorrow. Either way there can be no future contingencies. Although some hold that Aristotle would embrace the determinism they find implicit in this consequence, most argue either that he suspends the law of excluded middle for future contingencies or that he denies the principle of bivalence for future contingent statements. On the first option Aristotle gives up the claim that either the sea battle will happen tomorrow or not. On the second he keeps the claim but allows that future contingent statements are neither true nor false. Aristotle’s evident attachment to the law of excluded middle, perhaps, favors the second option.
Prior Analytics marks the invention of logic as a formal discipline in that the work contains the first virtually complete system of logical inference, sometimes called syllogistic. The fact that the first chapter of the Prior Analytics reports that there is a syllogism whenever, certain things being stated, something else follows of necessity, might suggest that Aristotle intended to capture a general notion of logical consequence. However, the syllogisms that constitute the system of the Prior Analytics are restricted to the basic categorical statements introduced in On Interpretation. A syllogism consists of three different categorical statements: two premises and a conclusion. The Prior Analytics tells us which pairs of categoricals logically yield a third. The fourteen basic valid forms are divided into three figures and, within each figure, into moods. The system is foundational because second- and third-figure syllogisms are reducible to first-figure syllogisms, whose validity is self-evident. Although syllogisms are conveniently written as conditional sentences, the syllogistic proper is, perhaps, best seen as a system of valid deductive inferences rather than as a system of valid conditional sentences or sentence forms.
Posterior Analytics extends syllogistic to science and scientific explanation. A science is a deductively ordered body of knowledge about a definite genus or domain of nature. Scientific knowledge (episteme) consists not in knowing that, e.g., there is thunder in the clouds, but rather in knowing why there is thunder. So the theory of scientific knowledge is a theory of explanation and the vehicle of explanation is the first-figure syllogism Barbara: If (1) P belongs to all M and (2) M belongs to all S, then (3) P belongs to all S. To explain, e.g., why there is thunder, i.e., why there is noise in the clouds, we say: (3H) Noise (P) belongs to the clouds (S) because (2H) Quenching