The First Great Platonist and Plato's First Great Critic

Plato, 427-347 BCE.   Aristotle, 384-322 BCE.

Raphael Sanzio da Urbino (1483-1520), The School of Athens
Plato and Aristotle, the School of Athens
Plato points to a "higher" reality. Aristotle points forward. He accepts what he regards as the central parts of Platonism, but he also is a critic who eliminates its excesses.

Plato holds a copy of the Timaeus, a late dialogue devoted to cosmology. Aristotle holds a copy of a work in ethics.

The titles TIMEO and ETICA on these books translate from Italian into English as TIMAEUS and ETHICS.
Aristotle belongs to the Period of Schools. He entered Plato's Academy in 367 BCE when he was seventeen and remained until Plato's death in 347 BCE. In 335 BCE, he founded his school in the Lyceum (located outside and east of Athens's city wall).

The works in the Aristotelian corpus as we now have it are esoteric (written for members of the school) and organized systematically into roughly three parts. The logcial works come first. They are followed by the physical works. The ethical works are last.

For Plato, unlike for Aristotle, we have a good idea of the rough order in which he wrote the works in his corpus. This gives us a rough order of the development of his thought. Further, Plato did not write most of dialogues expressly for insiders. He models his early dialogues on conversations Socrates, and Socrates's conversations were not with philosophers. This gives us a fighting chance to understand what Socrates and Plato were thinking.

None of this is true for Aristotle. His works are largely a series of compressed notes.

How to Approach the Corpus

Outside a history class, the Nicomachean Ethics is what most students read. From the point of view of the corpus, this is start close to the end. To understand Aristotle's contribution to the history of philosophy, it is better to start closer to the beginning of the corpus.

We begin with the physical works and what Aristotle calls "second philosophy."

An interest in the existence of natural bodies had emerged as part of the reaction to the inquiry into nature, but it receded when Socrates focused attention on ethical matters.

Later, in the Timaeus, when Aristotle was in the Academy, Plato gave new life to this interest.

Socrates is a character in the Timaeus, but Timaeus leads the discussion. He is the "best astronomer and has made it his special task to know about the nature of the whole." His discussion begins with "the origin of the cosmos" and ends "with the generation of man" (27a). In this discussion, which spans most of the dialogue, he explains the existence of natural bodies in terms of forms (27d), the divine maker ("artificer" or "demiurge" (δημιουργός) who is good and who arranges things so that the cosmos he fashions is as like himself as possible (28a), and the "receptacle" (ὑποδοχή) that becomes like the forms (49a).

We are not going to try to understand this view in any detail.

We are interested in it for the context it provides for understanding Aristotle. He works within the general understanding of natural bodies that Timaeus sets out, but he also tries to remove the problems he sees. He accepts the teleological explanation, but he rejects the demiurge. He understands the existence of natural bodies in terms of forms, but he does not think these forms exist in the way Timaeus describes. Instead of the receptacle, Aristotle has matter.

Aristotle's conception of natural bodies is the subject of this and the next several lectures.

The Existence of Natural Bodies

Aristotle conceives of natural bodies as having a kind of "being" or existence that distinguishes them as natural bodies. Humans, for example, have a kind of being. The same is true for dogs, cats, the moon, and the stars. These things have different ways of getting through time, but they all are instances of the existence that characterizes something as a natural body.

In so thinking about natural bodies, Aristotle rejects the approach the inquirers into nature took in their response to Parmenides. They rejected the existence of what we ordinarily take to exist (the drops of water, for example, that form in the sky and fall to the ground when it rains) because they thought with Parmenides that nothing comes into or goes out of existence. Democritus, for example, thought that only atoms and void really exist and those who thought otherwise are relying on experience as opposed to reason to know what exists.

Instead of this approach to understanding natural bodies, Aristotle thinks that

• natural bodies have a "nature" (φύσις)
• this nature is the organization of the material that constitutes the body
• this organization of the material is a "form" (εἶδος)

This conception of natural bodies will take some time to understand.

The first step is to think about why Aristotle understands the study of natural bodies as what he calls δευτέρα φιλοσοφία and whose traditional translation is "second philosophy."

Demonstration, Definition, and Form

Aristotle takes the nature of natural bodies of a given kind to be necessary for the "knowledge" (ἐπιστήμη) about these natural bodies set out in a "demonstration" (ἀπόδειξις).

Definitions are starting-points for demonstrations. They specify the nature of natural bodies of the given kind. This specification is the The Latin essentia and substantia translate οὐσία.

οὐσία is formed from a participle of εἶναι ("to be") and the noun-forming suffix -ία. Latin had the suffix -ia but not the participle of esse ("to be"). So the participle essens was introduced to create essentia in imitation of the way οὐσία is formed. Seneca, in his Epistles 58.6, uses essentia and cites the authority of Cicero to justify it as a Latin word.

For the imperfect in τὸ τί ἦν εἶναι, see Smyth 1901-1902 and "F" in the entry for εἰμί in Liddell and Scott.
"essence" (or "what it is to be" (τὸ τί ἦν εἶναι)) of these bodies. The definition specifies the essence of the kind of the natural bodies. A demonstration is a deductive argument (a "syllogism" (συλλογισμός)) that shows that these natural bodies have their specific behaviors (the behaviors common to natural bodies of the kind) because these bodies instantiate the essence specified in the definition.

Aristotle discusses demonstration in the logical works. Like the Aristotelian corpus generally, the logical works are organized systematically. The Categories is first in the series. It discusses terms, the parts of sentences. On Interpretation is second. It discusses sentences, the parts of syllogisms. The Prior and Posterior Analytics follow On Interpretation. The Prior Analytics discusses syllogisms, and the Posterior Analytics discusses demonstrations.

"A deduction (συλλογισμός) is an argument in which, certain things having been supposed, something different from those supposed results of necessity because of their being so" (Prior Analytics I.1.24b). "The reason why we must deal with deduction before we deal with demonstration is that deduction is more universal; for demonstration (ἀπόδειξις) is a kind of deduction, but not every deduction is a demonstration" (Prior Analytics I.4.25b).

"The starting-point of every demonstration is the what it is (τὸ τί ἐστιν)" (On the Soul I.403a).

In a syllogism, there are three terms: "subject" (S), "middle" (M), and "predicate" (P). Each premise has one term in common with the terms in the conclusion. In the major premise, the predicate is the common term. In the minor premise, the subject is the common term.

It is customary to write the major premise first. This can seem unnatural until one realizes Aristotle does not write "All M are P." Instead, he writes "P is predicated of all M." So when the premises and the conclusion are expressed in the form Aristotle uses, the demonstration

All M are P
All S are M
All S are P

takes the form

P is predicated of all M
M is predicated of all S
P is predicated of all S

"For if A is predicated of all B, and B of all C, A must necessarily be predicated of all C" (Prior Analytics I.4.25b).

Aristotle's theory of the syllogism is major achievement in logic that was only surpassed in the last hundred years or so.
In the physical works, Aristotle does not present demonstrations. These works are investigations, not discussions of the demonstrations that constitute second philosophy, but the following example (which has its basis in the Aristotelian idea that rational animal is the essence of man) makes it a little clearer what a demonstration is:

Rational animals make discriminations in terms of sensation.  (All M are P)
Human beings are rational animals.                                           (All S are M)
Human beings make discriminations in terms of sensation.      (All S are P)

This demonstration displays some of the structure of a human being. They have a nature. It is given in the second premise that defines "what it is to be" a human. If material is organized in the form specified in this definition, then this material is not a heap. It is a human being, and it has the power to make discriminations in terms of sensations. Every human beings has this power because the organization of its material as a rational animal (and thus as a human being) organizes it so that it has the power to make discriminations in terms of sensations.

Notice that this way of trying to understanding natural bodies makes no mention of laws of nature. Aristotle does not have the idea that there are laws that govern and explain the behavior of all objects, irrespective of the kind to which these objects belong.

This is one important way the Ancient world view is very different from the modern view.

The Life of Contemplation

Given Aristotle's understanding of demonstrations, we can see that he is following Plato by conceiving of the subject he pursues in the physical works as φιλοσοφία or "philosophy."

Plato, in the Phaedo, makes Socrates describe the φιλόσοφος as someone who devotes his life to knowledge of forms. Since physics for Aristotle is a study of the forms of natural bodies, he thinks of it as a kind of φιλοσοφία. He thinks of it, though, as second philosophy because the forms of natural bodies are second to the objects of study in first philosophy.

To get straight on how Aristotle understands this "secondness," we need to take a closer look at how he understands the existence of forms and existence more generally.

We do this in subsequent lectures as we consider more of what Aristotle thought.

Reason, Knowledge, and Induction

One question we might ask about demonstrations is how we know what the essences are.

Aristotle explains this knowledge in a way he thinks corrects a mistake Plato made.

Aristotle thinks that human beings naturally come to possess reason and the knowledge that belongs to reason. This happens in a process he calls "induction" (ἐπαγωγή). In this process, humans acquire reason as they acquire certain basic concepts about the world and the knowledge these concepts embody.

We can see, then, in connection with the Theory of Recollection in the Plato's Meno and Phaedo, that Aristotle accepts the epistemological thesis about reason but denies the ontological thesis about the soul.

We will think more about this and Aristotle's understanding of the soul in subsequent lectures.

Thinking about Aristotle

We have begun to see how Aristotle fits into the history of Ancient philosophy. He supplies missing details in the thinking he knew from his time in Plato's Academy and tries to remove what he regards as its mistakes and excesses. To understand how Aristotle does this, we began by considering what he calls δευτέρα φιλοσοφία or "second philosophy." This approach has allowed us to identify some of Aristotle's thoughts, but it also raised questions about what exactly these thoughts are. I try to answers these questions in the next lectures.

Perseus Digital Library

Plato, Theaetetus, Timaeus
Aristotle, Metaphysics

Henry George Liddell, Robert Scott, A Greek-English Lexicon

ἀπόδειξις, apodeixis, noun, "showing forth, making known, exhibiting"
ἐξωτερικός exōterikos, adjective, "outer" (a comparative of ἔξω, exō, adverb, "out")
ἐσωτερικός, esōterikos, adjective, "inner" (coined to correspond to ἐξωτερικός)
φιλοσοφία, philosophia, noun, "love of wisdom"
συλλογισμός, noun, "computation, calculation"

Arizona State University Library: Loeb Classical Library:
Aristotle, Categories, On Interpretation, Prior Analytics, Posterior Analytics, Physics

"Aristotle wants to hold on to the metaphysical primacy of objects, natural objects, living objects, human beings. He does not want these to be mere configurations of more basic entities [as they are for the inquirers into nature], such that the real things turn out to be these more basic entities. But to look at an object just as the configuration of material constituents transiently happen to enter into is to look at the material constituents as the more basic entities" (Michael Frede, "On Aristotle's Conception of the Soul," 146. Essays on Aristotle's De Anima, 93-107).

"Horses are a kind of beings, and camels are a different kind of beings, but neither horses nor camels have a distinctive way of being, peculiar to them; they both have the way of being of natural substances..., as opposed to, e.g., numbers which have the way of magnitudes..." (Michael Frede, "The Unity of General and Special Metaphysics: Aristotle's Conception of Metaphysics," 85-86. Essays in Ancient Philosophy, 81-95).

"In [Posterior Analytics] B19, the crucial word 'logos' [λόγος], finally does occur, namely in 100a2. "[S]o that some come to have reason (λόγον) ... and others not" (Posterior Analytics II.19.100a).

The Loeb translator (in the link) obscures the point.
It is used to refer to precisely the disposition of the mind or soul in virtue of which, or perhaps rather in which, we know first principles, and he talks of this disposition as something we come to acquire. I infer from this, though the conclusion seems striking and surprising, that Aristotle assumes that we are not born with reason, but acquire it, and that, in Aristotle's view, to have reason, to be fully rational or reasonably, is know first principles" (Michael Frede, "Aristotle's Rationalism," 169. Rationality in Greek Thought, 157-173). "Aristotle quite explicitly says (APo. B19.100a2) that reason only comes into being as we acquire the appropriate concepts of things and thereby the knowledge of things and their principles whose mastery of these concepts embodies" (Michael Frede, "Introduction," 11. Rationality in Greek Thought, 1-28).

"Aristotle's own view seems to be that to recognize reason as something apart from perception would involve a recognition of the intellect (νοῦς) with its distinctive active power to grasp terms or universals and thus the basic terms and the immediate truths about them from which all other scientific truths can be deduced, a power which, though (at least in the case of human beings) causally linked to, and in a way based on, perception, nevertheless epistemologically is an independent source of knowledge, in fact the source of all knowledge properly speaking" (Michael Frede, "An Empiricist View of Knowledge: Memorism," 236. Companions to Ancient Thought 1. Epistemology, 224-250).

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