Reier Helle

Research

“Hierocles and the Stoic Theory of Blending” (Phronesis 63.1, 2018): published, draft

Abstract: In Stoic physics, blending (κρᾶσις) is the relation between active pneuma and passive matter; natural bodies from rocks and logs to plants, animals and the cosmos itself are blends of pneuma and matter. Blending structures the Stoic cosmos. I develop a new interpretation of the Stoic theory of blending, based on passages from Hierocles. The theory of blending, I argue, has been misunderstood. Hierocles allows us to see in detail how the theory is supposed to work and how it fits into Stoic physics.

“Self-Causation and Unity in Stoicism” (Phronesis 66.2, 2021): published, draft

Abstract: According to the Stoics, ordinary unified bodies—animals, plants, and inanimate natural bodies—each have a single cause of unity and being: pneuma. Pneuma itself has no distinct cause of unity; on the contrary, it acts as a cause of unity and being for itself. In this paper, I show how pneuma is supposed to be able to unify itself and other bodies in virtue of its characteristic tensile motion (τονικὴ κίνησις). Thus, we will see how the Stoics could have hoped to account for corporeal unity by positing another body (pneuma) apparently itself in need of unification.

“Colocation and the Stoic Definition of Blending” (Phronesis 67.4, 2022): published, draft 

Abstract: This paper considers what function—if any—colocation of bodies may have in the Stoic theory of blending (κρᾶσις), by examining (1) whether colocation is part of the definition of what blending is; and (2) whether colocation is posited by the Stoics as a requirement necessary for the definition to be satisfied. I reconstruct the standard, Chrysippean definition of blending, and I show that the answer to (1) is ‘no’; further, I argue that the evidence gives no reason to affirm (2). Thus, it appears that colocation does not have a central function in the Stoic theory of blending.

“Alexander of Aphrodisias and the Stoics: Blending, Forms, and the Upwards Story” (in The History of Hylomorphism: from Aristotle to Descartes, Charles, D. ed., Oxford University Press, 2023)

Abstract: This chapter considers the clash between Alexander of Aphrodisias’ version of hylomorphism and the Stoic theory of pneuma-matter blending. For the Stoics, animals, plants, and inanimate natural bodies are composed of pneuma (‘breath’) and matter, and by blending with matter pneuma causes the composite to be what it is. Alexander argues that the Stoic theory is explanatorily inadequate, because pneuma cannot do the causal work needed, and Stoic blending cannot yield a unified whole. I examine Alexander’s objections, and I develop an account of how he means to avoid similar deficiencies in his own hylomorphic theory. While the Stoics face significant explanatory problems, Alexander’s view, it turns out, is not without difficulties. For the explanatory role given to the underlying bodies and their manner of combination (‘the upwards story’) leaves Alexander without a precise account of how and why the material basis is connected to the form of the composite.