Topoi and Commonplaces: Rhetoric's Generative Argument Patterns

When Aristotle organized the process of rhetorical invention; the systematic generation of arguments; his central tool was the concept of topoi, or "places" (Latin: loci). The term is spatial: a topos is a place in the mind where arguments of a certain kind are found, a generative pattern that can produce relevant material when applied to any subject. Understanding topoi is understanding how skilled speakers and writers generate arguments systematically rather than waiting for inspiration.

Topos / Topoi (τόπος / τόποι)

Literally "place" (Greek). In rhetoric, a generative argument pattern or line of reasoning that can be applied across different subjects to produce specific types of arguments. Plural: topoi. Latin equivalent: loci (singular locus); sometimes rendered in English as "commonplaces."

Common Topoi vs. Special Topoi

Aristotle distinguished two types of topoi. Common topoi (koinoi topoi) are universal argument patterns applicable to any subject in any rhetorical genre; they produce arguments about any topic. Special topoi (idiai topoi) are domain-specific patterns applicable to particular subjects; they require substantive knowledge of the relevant field (politics, ethics, natural science) and are productive only in those contexts.

The common topoi are more abstract but more powerful as inventional tools precisely because they apply everywhere. Aristotle identified several fundamental ones:

More and Less (Degree)

If X is true of something to a lesser degree, it is true of something to a greater degree; and vice versa. "If even just laws can be unjust in certain circumstances, surely unjust laws can be unjust in all circumstances."

Opposites

If one of a pair of opposites has a given quality, so does the other. "If war is the cause of these troubles, then peace is the cure."

Correlation

If two things are correlated, what is true of one is true of the other. "If the goal is honorable, the means of achieving it are also honorable."

Past Fact

If something more unlikely happened, then something more likely also happened. "If she could persuade him to change his vote after twenty years of hostility, she can surely persuade a sympathetic audience."

Definition

Arguments about what a thing essentially is generate arguments about what should be true of it. "If a leader is defined by their willingness to make hard decisions, then..."

Cause and Effect

From cause to effect, or effect to cause. "If this policy is implemented, the likely effect will be..." or "Given this observable effect, the cause must be..."

Topoi and the Memory Tradition

The concept of topoi is etymologically connected to the classical memory tradition: both use the spatial metaphor of "places" in which things are stored and found. The memory palace technique places images (imagines) in loci (places) to be retrieved; the inventional topoi are intellectual loci in which argument patterns are found.

This connection is not merely metaphorical. Both practices train the mind to search systematically for what it needs, rather than relying on random inspiration. The practiced rhetorician develops an internalized repertoire of topoi that can be surveyed quickly in any argument situation; a systematic coverage of the available argumentative ground that ensures no productive line of reasoning is missed.

Renaissance and Modern Applications

The topoi tradition survived the Renaissance and continues to inform contemporary writing and argument pedagogy. Modern invention heuristics; strategies for generating ideas about any subject; are descended from the classical topoi. Questions like "What is it? What caused it? What are its effects? What are its parts? What are its opposites? What examples illustrate it?" are adaptations of classical inventional patterns applied to contemporary writing education.

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