This illuminating study proceeds according to what Peter T. Struck calls a “central axiom”: our ability to know exceeds our capacity to understand that ability. In cognitive science, it is well established that we know certain things without understanding how we know. Divination is “just the most robust ancient version in a long series of attempts” to express this “surplus knowledge.” The social and political dimensions of divination are not its drivers; they happen posterior to, and as an epiphenomenon of divination, which is driven by the existence of surplus knowledge or intuition, “an underlying characteristic of the nature of human cognition.” Struck’s goal, then, is to show that in the Classical world, divination filled the role that the concept of intuition fills in the modern world.
Struck points out that the study of divination by classicists usually focuses on its political aspects and social functions, or on its supposed kinship with magic. Both of these approaches have limitations. Although magicians practiced divination, so did virtually everyone else, and manteia enjoyed a different, much higher cultural status than did goēteia. The link moderns have perceived between divination and magic seems to lie in the fact that we tend to consider both practices “irrational,” and find them out of place in a culture that we presume to be guided by logos.
The Greeks and Romans distinguished between “natural” modes of divination (via dreams, visions and oracles) and technical modes (via signs in livers, flames, birds, etc.). Struck argues that the emic distinction is fuzzy. Both modes draw upon intuition, he suggests, for the technical modes do not function strictly “by the book” and in the unusual cases where books exist, as in the Roman augural law, the profusion of complex rules seems more a hindrance than a help. Granted that there was some room for intuition in the technical modes, these modes still depended on bodies of knowledge, which must be learned through oral transmission, observation, and experience. This is a weakness in Struck’s thesis, for the craft involved in technical divination cannot be equated with intuition.
In Chapter 1, “Plato on Divination and Nondiscursive Knowing,” Struck shows that in Plato’s works, the verb manteuomai is often used to describe the advent of ideas or judgments in the mind without an intervening process of reasoning, much as an English speaker might say “I have divined your purpose,” but in more abstract contexts, such as perceiving the similarities between temperance and harmony. From this starting point, the thought is then tested through discursive means. Thus “divining” is Plato’s preferred metaphor for what we would call intuition or insight.
The “divining” of which Plato speaks, and which Struck describes as “a kind of knowing that happens in a flash,” would seem to exclude the technical varieties of divination, for these by definition do not happen in a flash, but require the intermediary step of a sign, which must then be interpreted, however quickly, and however flexible the relevant rules. On the other hand, Socrates’ daimonion, which he calls his “customary sign,” seems to be a hybrid, for on the one hand, it functions like an inner voice, but on the other, it appears unbidden like an oblative sign and it calls for interpretation. Socrates is forbidden to do something, but why? The answer always depends on discursive examination of the problem, just as the Delphic oracle about Socrates demanded examination before its true meaning could be discerned.
Struck is sometimes too zealous to find the language of divination, as for example in his discussion of Phaedr. 249c-d where the diction is more closely related to mystery cults, and he admits that the connection is “indirect.” For me this raised the question of how Plato’s use of divination relates to his use of other kinds of Greek ritual. Does he functionally equate divinatory knowledge with mystery experiences and possession, and if so, what impact does this have on Struck’s thesis?
The Timaeus includes a difficult discussion of how the highest part of the soul, situated in the head, controls the lower soul by manipulating the liver to frighten or soothe it. Calm facilitates the liver’s reception of divinatory images, but such reception can only happen when the upper soul is not in control—during sleep or any altered state such as enthousiasmos ( Tim. 71e). Thus, as Struck points out, for Plato the appetitive soul has the ability to arrive at knowledge through nondiscursive means. But here again, Plato invokes enthousiasmos as an alternative way to allow the lower soul to become receptive, and in doing so, he seems either to broaden the activity of the liver beyond the clearly divinatory (to epiphanies for example), or to broaden the definition of manteia beyond the simple reception of non-discursive knowledge.
Chapter 2, “Aristotle on Foresight Through Dreams,” addresses Aristotle’s view that non-coincidental prescient dreams exist and his explanation of them in three treatises on sleep and dreaming. Acknowledging the difficulties in the text and interpretation of these treatises, Struck proposes an elegant new interpretation of a key sentence about the goal of the investigation ( Somn. 453b21-5). Rather than asking whether there is a difference in our ability to foresee events with different types of causation (human and daimonic/natural), Struck suggests that Aristotle’s question is whether divination itself is an act performed by humans on their own, or has a daimonic/natural cause. This is significant for our understanding of the treatise On Divination During Sleep, for the current consensus seems to be that Aristotle is attempting to deny or debunk any explanation of predictive dreams that invokes the divine. Instead, Struck argues cogently that Aristotle assigns the causation of such dreams to the daimonic, defined as the mode through which the divine acts in the natural world. Like consistent luckiness, the ability to experience predictive dreams results from impulses within the lowest or nutritive soul ( threptikon), which are in turn attributable to the daimonic.
Aristotle concludes that conscious, discursive reasoning and inspired divination are mutually exclusive. In order to prophesy, one must be empty-headed, at least temporarily; it is this property that allows the daimonic to operate, opening a channel for its teleological impulse toward the good. Like Plato, he contrasts this divination by the empty-headed with less accurate, empirical methods of divination.
When Struck refers to “divination” in the first two-thirds of the book, what he usually means is “inspired divination,” whether through dreams, oracles, or various forms of possession. This changes in Chapter 3, “Posidonius and Other Stoics,” for the Stoic explanation of divination applies to both technical and inspired methods. (Struck focuses primarily on Cicero’s De Divinatione 1.118-32, with its arguments attributed to Posidonius, but surveys other sources, showing in the process that divination was a key topic for the Stoics.) Because the Stoic universe, including air, inanimate objects and living organisms, is permeated by divine pneuma, any part of the cosmos can affect any other part through this medium; the phenomenon is known as sympatheia, “co-feeling.” Furthermore, the “seeds” or causes of future states are contained in the pneuma, which collectively forms a “world soul.” Causes and effects unfold according to predictable patterns, which technical diviners can observe (for example, in animal entrails or bird flight), while inspired divination happens when the pneuma of an individual’s soul is released from the normal demands of waking life, allowing it to be directly affected by divine soul(s).
The Stoic explanation of inspired divination fits Struck’s model of surplus knowledge; like the Platonic and Aristotelian theories, it involves a suspension of the waking, reasoning faculty. Struck has more difficulty showing how a Stoic account of technical divination results in surplus knowledge, for if predictable patterns in signs exist, divination converges with the empirical sciences. Discarding Cicero’s examples, which point to such a convergence, Struck argues that Posidonius’ position offers a higher-level explanation of patterns in signs ( sympatheia), yet maintains that the specifics of the relationships involved are impervious to reason.
In Chapter 4, “Iamblichus on Divine Divination and Human Intuition,” Struck shows how Neoplatonism represents a decisive break with previous philosophical positions on divination. First, the Neoplatonists disavow the physiological, material factors that were essential for Plato, Aristotle and the Stoics. Second, they lack interest in the context-driven parameters of traditional divination, which was aimed at practical answers to questions about how to proceed in a given situation.
In a sharp turn away from his predecessors, Iamblichus proposed that “true” divination was a method of knowing the deep structure of the cosmos. The Neoplatonists were dismissive of traditional divination, because it did not aim to produce transcendent experience or revelatory wisdom. For Porphyry, traditional seers might achieve limited success in tracing connections within the physical world (e.g., between sheep entrails and events), but there is nothing divine in physical signs. In his De Mysteriis, Iamblichus distinguishes between lower and higher, “true” forms of the mantic art. The lower forms depend on guesswork, observation of correlations in nature, and the activities of inferior daimones, but only the higher forms involve divine agency.
Iamblichus rejects the older theory that people experience predictive dreams or other divine phenomena when the reasoning faculties are at their ebb; for him the opposite must be true. Only through the exercise of the “highest mind” can humans make the ascent to the divine, and only this transcendence of the material world is worthy of the name mantikē. Iamblichus therefore proposes a term for the natural ability to gain knowledge without being able to account for it: epibolē, or as Struck translates it, “intuition.”
It would be interesting to know whether non-philosophical Greek texts consistently attribute knowledge generated unconsciously to external, divine sources. In the book’s conclusion, Struck applies the divinatory = intuitive hypothesis to the interpretive questions in the Odyssey surrounding Penelope’s struggle for certainty about Odysseus’ identity, and makes a convincing case that the abundant signs in Books 19 and 20 can be read as emic expressions of our etic concept of intuition (knowledge which arises non-discursively and without conscious inference).
This is an absorbing work of intellectual history, demonstrating a confident command of the philological and philosophical issues, and lucidly exploring Greek philosophical engagement with the epistemological and theological puzzles presented by divination. The book offers a fresh approach to the topic of divination by juxtaposing it with ancient and modern theories of cognition, and by moving past the debate over the (ir)rationality of the practice. Struck asks why the Greeks found divination so convincing as a way of generating knowledge, and shows how educated thinkers in antiquity explained (and in the case of the Neoplatonists) ultimately rejected traditional divination. This demonstration does not fully address the reasons for popular acceptance of divination, although Struck hints that awareness of intuitive forms of knowledge must have played a role. I hope that this excellent study will stimulate further research into such questions.