Collections (2): From Aristotle to Boethius

1. Aristotle, Rhetoric (between 329 & 323 b.c)

1.1 The catalog and its position in the system of Aristotelian proofs

The catalog of the Rhetoric must be viewed within the framework of the Aristotelian typology of the different types of reasoning carried by different types of discourses. In this typology of proofs, rhetorical discourse is opposed to dialectical dialogue and to scientific (syllogistic) discourse. Tricot points out that “syllogism is the genre, scientific (producer of science) [is] the specific difference that separates the scientific demonstration from the dialectical and rhetorical syllogisms” (S. A., I, 2, 15-25; p. 8, note 3). The concept of persuasion in the Rhetoric must be seen in this context: scientific discourse produces apodictic knowledge, dialectical interaction produces probable truth and rhetorical syllogism or enthymeme is an element of persuasive discourse. Thus, by its very definition, rhetorical discourse cannot be probative; in short, the phrase “rhetorical evidence persuades” is a pleonasm.

The catalog of arguments is situated as follows in the sub-typology organizing the rhetorical proofs (proof = pistis, “means of pressure”).


1.2 Wavering distinctions

Aristotle establishes the following distinctions between the various kinds of rhetorical proof:

  Technical Ethos  
    Logos Enthymeme


The proofs attached to the logos are enthymemes, which correspond to deduction; examples@, which corresponds to induction; and arguments based on natural signs, that are probable or certain. Enthymeme and example are said to be common to the three ancient rhetorical genres (epideictic, deliberative, judicial, S. Rhetoric.) But the articulation of these different kinds of proofs, and the consistency of the text of the Rhetoric such as we read it now, is problematic (McAdon 2003, 2004). The classification of proofs attached to logos has important variants:

(a) “I call an enthymeme a rhetorical syllogism, and an example rhetorical induction. Now all orators produce belief by employing as proofs either examples or enthymemes, and nothing else.” (Rhet., I, 2, 8; Fr., p. 19)

(b) “the materials from which the enthymemes are derived […] being probabilities and signs […].” (Ibid I, 2, 14; p. 25)

(c) “Now the material of enthymemes is derived from four sources — probabilities, examples, necessary signs and signs.” (Ibid II, 15, 8; p. 337)

The example is placed on the same level as the enthymeme in (a), but is considered a form of enthymeme in (c); enthymemes have four sources in (c), and two in (b). Thus, it would be risky to look for a rigorous system in these presentations of rhetorical proof, and the above table must be considered as a simple reminder.

1.3 The topoi of the Rhetoric

The Rhetoric enumerates twenty-eight topoi (topics) or “lines of argument” (Rhet, II, 23), as listed in the following table. An enthymeme is a discursive instance of a topos.

They are designated by their English label, when available, or by a short description, both quoted from Freese (F) or Rhys Roberts (RR).

      1. “From opposites” (F). S. Opposites
      2. “From similar inflexions” (F). S. Derived Words
      3. “From relative terms” (F);“upon correlative ideas” (R). S. Correlative Terms
      4. “From the more or less” (F); a fortiori (R). S. A fortiori
      5. “The consideration of time” (F). S. Consistency
      6. “Turning upon the opponent what has been said against ourselves” (F). S. Ethos; A fortiori.
      7. “From definition” (F). S. Definition
      8. “Topic from the different significations of a word” (F). Aristotle explicitly refers to this topos in his Topics. S. Ambiguity.
      9. “From division” (F). S. Case-by-case
      10. “From induction” (F). S. Induction
      11. “From a previous judgment in regard to the same or a similar or contrary matter”, this judgment having been given by one of “those whose judgment it is not possible to contradict” (F). S. Precedent; Ab exemplo; Authority; Modesty; Politeness
      12. “From enumerating the parts” (F). S. Case-by-case
      13. “Since in most human affairs the same thing is accompanied by some bad or good result, […] employing the consequences to exhort or dissuade, accuse or defend, praise or blame” (F). S. Pragmatic argument; Dilemma
      14. [id. 13], “but there is this difference that in the former case [i.e., 13] things of any kind whatever, in the latter [i.e., 13] opposites” (F). S. Pragmatic; Dilemma
      15. “Men do not praise the same thing in public and in secret” (F). S. Motives
      16. “From analogy in things” (F). S. Analogy; Opposites.
      17. “Concluding the identity of precedents from the identity of results” Instance: “There is as much impiety in asserting that the gods are born as in saying that they die; for either way the result is that at some time or other they did not exist” (F). S. Consequence; Implication.
      18. “The same men do not always choose the same thing before and after but the contrary” (F).  S. Consistency.
      19. “Maintaining that the cause of something which is or has been is something which would generally, or possibly might be the cause of it; for example, if one were to make a present of something to another, in order to cause him pain by depriving him of it” (F). S. Motives
      20. “Examining what is hortatory and dissuasive, and the reasons which make men act or not” (F). S. Motives
      21. “Things which are thought to happen but are incredible” (F). S. Probable.
      22. “Another line of argument is to refute your opponent’s case by noting any contrast or contradiction of dates, acts or words that it anywhere displays” (RR). S. ContradictionConsistency; Ad hominem.
      23. “Another topic, when men or things have been attacked by slander […] consists in stating the reason for the false opinion” (F). S. Motives; Interpretation
      24. “Another topic is derived from the cause. If the cause exists, the effect exists; if the cause does not exist, the effect does not exist” (F). S. Motives
      25. “Whether there was or is another better course than that which is advised, or is being, or has been carried out” (F). S. Consistency; Motives
      26. “Another topic, when something contrary to what has already been done is on the point of being done, consists in examining them together” (F). S. Consistency
      27. “Another topic consists in making use of errors committed for purposes of accusation or defense” (F). S. Contradiction; Consistency
      28. “From the meaning of a name” (F). S. Proper Name

Even if no clear order emerges from this enumeration, it can be noted that an important subset of topics deal basically with the world of human action and its determination, where motives have been substituted for causes, and behavioral stereotypes on human nature and human motivations have replaced strict scientific causality and taxonomies.


2. Cicero, Topica, “Topics” (44 b. c.)   

Cicero proposes a typology of arguments in an early work, De Inventione, “On Invention” and in his latest book on argument, Topica, “Topics”. Unlike the Topics of Aristotle, which exposes a method of finding and criticizing arguments in the context of a dialectical philosophical exchange, Cicero’s observations and examples constantly refer to rhetoric as a judicial practice. In this context, Cicero proposes the following distinction:

  • Intrinsic arguments, either “inherent in the very nature of the subject which is under discussion” or “closely connected with the subject which is investigated” (, I, 8; p. 387-389).
  • Arguments taken “from external circumstances”, or “extrinsic arguments” (, II, 8; p. 388; IV, 24, p. 397), corresponding to the so-called non-technical@ arguments, mainly testimonies and their conditions of validity, and including authority (Top., IV, 24; p. 397).

Objects and facts are built and discussed on the basis of arguments drawn from five main sources.


From definition. Arguments:

— by genus and species of the genus (a genere; a forma generis).
— by enumeration of the parts (partium enumeratio)
— from “etymology” (ex notatione)
— from words of the same family (a conjugata)
— “based on difference” (a differentia).

S. Categorization and Nomination; Definition; Genus; Case-by-case; True meaning of the word; Derived Words


From causal relations S. Causality. Arguments: ­

— from efficient causes (ab efficientibus causis)
— from effects (ab effectis).


From analogy (a similitudine).

S. A pari; Intra-categorical analogy; Structural analogy


From opposites (ex contrario).

S. Opposites


From circumstances. Arguments: ­

— from antecedents, ab antecedentibus,
— from consequents, a consequentibus

S. Circumstances


This brief and articulated list of arguments is all important in the Western tradition of argumentation studies. They were transmitted in the Middle Ages by Boethius (around 480-524) On Topical Differences (Top., c. 522), and were taken up by medieval logic, dialectic and philosophy. They remained in use until well into the modern era, S. Collections (3).

3. Quintilian, Institutio Oratoria, “The Orator’s Education” (c. 95)

In Book V, Chap. 10 of the Institutes of Oratory, dealing with arguments, Quintilian summarizes a list of 24 argumentative lines (IO, V, 10, 94). A first series deals with common places.

A second series is a catalog of argument schemes: the French translator, J. Cousin, notes that

“this list-summary, which seems to be a loan, recalls previous classifications, with their elements arranged in a different order: […] Later rhetoricians condense or develop without apparent reason” (1976, p. 240).