Sunday, January 30, 2011


Henry Dyson, Prolepsis and Ennoia in the Early Stoa. Berlin/New York: Walter de Gruyter, 2009. Pp. xxxiii, 265. ISBN 9783110212280. $99.95.

Reviewed by Scott Rubarth, Rollins College (

Version at BMCR home site


Henry Dyson's Prolepsis and Ennoia in the Early Stoa is a careful and thorough analysis of the theory of natural conceptions in Stoicism. The book examines the scholarly debate regarding the nature and function of preconception (πρόληψις), common conception (κοινὴ ἔννοια), and natural conception (φυσικὴ ἔννοια) and presents a novel theory of how these terms and mental entities operate in the Stoic theory of cognition. In the process of sorting out the fine distinctions in Stoic technical terminology and navigating a complex debate in the secondary literature, Dyson manages to unpack, analyze, and piece together again a whole host of related historical and philosophical issues in Stoic epistemology, psychology, metaphysics, action theory, logic, and philosophy of language. In short, this study is an example of how what seems to be a narrow philological problem can produce significant conclusions beyond the scope of the original problem by means of detailed, careful, and, in this case, nearly exhaustive analysis.

The author begins by asking, does the Stoic account of conceptual and intellectual development, as Cicero and Epictetus tell the story, represent a rationalist Academic distortion of the more empiricist early Stoic theory, or do they fairly represent a consistent Stoic doctrine beginning in the early Stoa? To answer this question Dyson takes the reader on a long and convoluted journey through, as far as I can tell, all the relevant texts and nearly every scholarly interpretations remotely dealing with conceptual development.

In the first chapter, Dyson seeks to establish the theoretical unity of πρόλεψις, κοινὴ ἔννοια, and φυσικὴ ἔννοια. In order to do this, he must first establish whether these three terms are technical or generic terms and if the terms represent different kinds of conceptions. Sandbach and others, representing the orthodox reading of πρόλεψις, argue that προλήψεις and common conceptions differ in meaning and scope. Dyson attempts to refute Sandbach's orthodox view and concludes that all three are "interchangeable terms referring to a single underlying doctrine in the early Stoa" (p. 1).

The second chapter, "Common Conceptions as Criteria of Truth," examines how προλήψεις and common conceptions are able to operate as criteria of truth. As in the former chapter, Dyson spends most of the chapter recounting and dismantling the major interpretations in the secondary literature. Gould, Frede, and Todd offer models of how προλήψεις function in the evaluation of sensory experience.1 While Dyson rejects the claim that προλήψεις are criteria for sensible presentations, he acknowledges that they do "form part of a background set of beliefs and conceptions that dispose the perceiver to react to presentations in certain ways" (p. 28). Next he turns to non-sensible presentations. Here Alexander of Aphrodisias' De Mixtione becomes the focus of the argument. Todd's interpretation (1973), which distinguishes between προλήψεις and natural conceptions on the one hand, and common conceptions on the other, becomes the foil to Dyson's central claim. The debate seems to center on the question, do common conceptions rest on conscious inferences? (p. 43) Dyson argues that they do not. Instead, common conceptions function unconsciously to structure experience conceptually (p. 54). In addition, epistemologically common conceptions, along with natural conceptions and προλήψεις, are naturally occurring and universal notions which "correspond to real divisions in the world" (p. 46) which in turn can be articulated in proofs. This correspondence claim, however, is not elaborated at this point and will require Dyson to explain how correspondence is possible given the problematic ontological status that the Stoics attribute to the ἐννοήματα.

The third chapter attempts to place the theory in the broader context of the development of rationality. First, Dyson seeks to secure the claim that common conceptions are tacit forms of belief universal to all human beings insofar as they are rational. Here Dyson's strong identity claim from chapter one is qualified. Πρόληψις and common conception no longer seem to be "interchangeable terms", since common conceptions are not identical with all προλήψεις but only with articulated προλήψεις (p. 50). Hence neither the sense nor the extension of the terms appears to be identical or interchangeable.

Identifying προλήψεις and natural conceptions as tacit beliefs creates a number of problems. How can one have a belief that one is unaware of? The answer lies in the distinction between articulated and unarticulated conceptions. On Dyson's model, an articulated common conception shares the same propositional content as its unarticulated counterpart in the πρόληψις or natural conception. Through cognitive development and the scrutiny of dialectic this content is accessed and utilized both in the development of knowledge and in action theory. These two stages in the development of reason are compared to the transition from sense-perception to memory and experience. Moreover, despite being unarticulated, the πρόληψις is still "psychologically functional" (p. 60), and insofar as all humans have potential access to this content, the πρόληψις is therefore also called "common."

Dyson also makes the claim that προλήψεις can be criteria of truth since they are true and we can know that they are true because providential Nature would not have formed them otherwise. If this was the Stoic position it is hard to imagine that this escaped the notice of critics. For such a criterion seems to beg the question. For a criterion of truth (unlike an axiom) need not and probably should not be a true proposition. This assumption could use more discussion. The idea of the transparency and veracity of nature stands in contrast to the more traditional Heraclitean maxim that nature loves to hide.

Chapter three concludes with a set of interim conclusions which help transition the reader to the next chapter by introducing the problem of universals through the claim that Chrysippus used the doctrine of πρόληψις to solve Meno's Paradox.

In chapter four, Dyson finally turns to a problem that has been lurking in the background of the former discussions: How do the προλήψεις serve as criteria of truth for universal claims given the nominalist ontology of the Stoics? If there are no forms (immanent or transcendent), what are the conceptions conceptions of? What is the intentional object of a πρόληψις or common conception? The Stoics, in fact, are fully aware of the problem and offer a solution: the ἐννόημα. The ἐννοήματα, like the φαντάσματα, (intentional objects of thoughts about non-existing entities like centaurs) have problematic ontological status. Dyson suggests that the ἐννόημα may be "a generic mental image produced by association" (p. 91). But this is surely wrong. The generic mental image produced by association would be the ἐννοία itself. Suggesting that ἐννόημα is a mental image instead of a logical entity removes the ontological problem recognized by the Stoics and creates a redundant mental event. Dyson makes a similar claim about the intentional object of memory. He states that "memory takes as its intentional object the mental image of a particular object." (p. 91) Instead, I would argue that the intentional object of the memory is the past event itself, which no longer exists. That is what the memory is about and that is why memory is logically interesting.

Fortunately Dyson subsequently distances himself from this account and instead, drawing on Chrysippus' rejection of Cleanthes' literal/pictorial view of φαντασία, argues for a linguistic turn in the development of the Stoic theory of concept formation. Dyson suggests that Chrysippus handles ἐννοήματα by developing a theory that reduces or analyses conceptions in terms of either descriptions or definitions based on syntactical relations. In short, a universal can be explained in terms of an indefinite conditional proposition.

Next Dyson examines how the πρόληψις and common conception function in Chrysippus's moral psychology and dialectic. He argues that προλήψεις are formed through perceptual experience and adds that the content "is formed by conditionally linking together the appellative that names a certain kind with other appellatives that can be applied to an object falling under that kind" (p. 133). Such is the foundation of tacit knowledge. The primary job of the πρόληψις, over and above its criterial role, is "to make connections between present presentations and general beliefs and conceptions" (p. 110). Dyson returns to the question of the structure of the πρόληψις and re-examines the two most promising alternatives: description and definition. Both are presented as conditionals and both offer a model for applying appellatives. Dyson argues that the definitional account is the correct interpretation and that the application of the definitional condition of the πρόληψις normally occurs at the tacit level. He then explains the role of πρόληψις in demonstration and dialectic by contrasting human reasoning and the more limited correlate in animals.

In the final chapter, Dyson returns to the question of where to align the Stoics in terms of rationalism and empiricism. Dyson supports a version of rationalism or nativism, at least in terms of justification. While the Stoic theory of concept-formation is clearly empirical, he holds that if we distinguish psychological empiricism from epistemological empiricism, one could argue that Stoic dialectic draws on a priori principles giving them a limited claim to rationalism.

The final chapter is followed by a valuable set of tables and appendices. The appendices are a wonderful addition to the book, especially given the dense and detailed nature of the argument proper. Each appendix presents both the primary text in Greek or Latin (albeit without a critical apparatus) followed by a translation. The eight appendices are organized chronologically and thematically. The book concludes with a bibliography and an index locorum. There are, however, no subject or author indices.

Henry Dyson's Prolepsis and Ennoia in the Early Stoa is a careful, rigorous, and philosophically productive analysis of the problem of conceptual development in Stoic philosophy. It is also a difficult and dense book most suitable to graduate students and specialists. The work assumes a knowledge of Greek and Latin as well as a general understanding of the major doctrines and sources for Stoicism. The erudite approach, however, means that the book is able to engage the philosophical and philological debate at a far deeper and detailed level than more accessible works in the field. The book is valuable both for its own impressive solution to the problem as well as its ability to unpack and narrate the twists and turns of the complex and extensive secondary literature. There is one significant and unnecessary flaw to the book. The work is absolutely riddled with typographical errors of all sorts. I counted roughly one hundred errors not including footnotes or appendices. This was a regular distraction in an otherwise very careful piece of scholarship. Yet despite this mild irritant, the work merits a careful reading and signifies an important philosophical and philological contribution to the field.


1.   Gould, J. B. The Philosophy of Chrysippus, Philosophia Antiqua. Leiden: E.J. Brill, 1970; Frede, Michael. "The Stoic Conception of Reason." In Hellenistic Philosophy, 50-63. Athens: International Center for Greek Philosophy and Culture, 1994; Todd, Robert B. "The Stoic Common Notions: A Re-Examination and Reinterpretation." Symbolae Osloenses 48 (1973): 47-75.

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