It is widely acknowledged that the vision of the divine represents the highest religious experience. However, for later Neoplatonists, vision (θεωρία), while profound, was not the final stage of the soul’s ascent. According to Iamblichus (c. 245-325 AD), Hermias (c. 410-455 AD), and Proclus (c. 415-485 AD), beyond vision—an intellective act—lies a higher stage: true union (ἕνωσις) with the divine. This union, achieved at the apex of theurgic ritual practice—when the ἑτερότης between human and divine dissolves, allowing for a single, unified activity between gods and humans—is not rooted in contemplation but in the activity of a distinct “part” of the soul: the “One.” This concept, absent (at least expressis verbis) from Plato’s Dialogues, was likely drawn from the Chaldean Oracles, i.e. the “Scriptures of the Hellenism” (P. Athanassiadi, “The Oecumenism of Iamblichus: Latent Knowledge and Its Awakening”, «The Journal of Roman Studies», vol. 85 (1995), pp. 244-250). This paper examines the correlation between intellect and vision on the one hand, and between the “One of the soul” and union on the other, demonstrating how later Neoplatonists redefined the highest stage of religious experience as an act beyond intellective vision. The discussion will be structured in two parts.
1. From the very prologue of his De mysteriis (Myst. 1, 2, p. 4, 16 – p. 5, 1 Saffrey/Segonds), Iamblichus makes a decisive distinction between theological vision and theurgic union. Theurgy, he asserts, is πεῖρα—an “experience.” It is not just some abstract concept to be discussed; it is something one must truly live. On this basis, Iamblichus carefully sets theurgy apart from theology. Talking about the gods does not equate to the direct “experience” of divine acts. This experience is so profound that it cannot be adequately expressed μόνον διὰ λόγων. Handling a theological issue in a manner consistent with theological principles means offering responses deeply rooted in intellective contemplation (νοερᾶς θεωρίας πλήρη), a process that requires purification (καθαίρεσθαι) and enables those who receive them to turn through their intellect toward the essence of beings (τῷ νῷ περιάγεσθαι πρὸς τὴν οὐσίαν τῶν ὄντων). When it comes to theurgy, the approach must shift significantly. One of the best examples of Iamblichus’ approach is found in Myst. VIII (4, p. 197, 23 – p. 198, 4). Egyptian priests are accomplished theologians who have skilfully teased apart the many layers of divine causes. And yet, Iamblichus continues to point out that
“this is not for them purely a matter of theorising, but they recommend that we ascend through the practice of sacred theurgy to the regions that are higher, more universal and superior to fate, towards the god who is the creator, without calling in the aid of matter or bringing to bear anything other than the observation of the critical time for action.” (Transl. E.C. Clarke, J.M. Dillon, and J.P. Hershbell, Iamblichus. De Mysteriis, Atlanta 2003).
Therefore, throughout the De mysteriis, Iamblichus drives home a critical point—intellectual vision is all well and good, even essential, but it is only part of the journey. The real aim is to “experience,” to rise up and connect with the divine principles themselves. While the vision of the intelligible realm depends on the proper purification of the intellect, true union with it occurs only when the divine aspect of the soul—the “One”—is awakened (Iambl. In Phaedr. fr. 6 Dillon).
2. This lesson would be inherited and further developed by Iamblichus’ successors in the Athenian School, namely Hermias and Proclus. Hermias actually labels as τὸ ἀκρότατον both the intellect and the “One of the soul,” implying that while the intellect is τὸ ἀκρότατον of the rational soul, the “One” is τὸ ἀκρότατον of the entire soul, because, carrying an ἴνδαλμα of the One beyond being, it unifies the entire soul (In Phaedr. 88, 23-29 Lucarini/Moreschini). His fellow disciple, Proclus, using Chaldean terminology, similarly distinguishes between the “flower of the intellect” and the “flower of the soul” (In CO. 4, 1-19 des Places; Theol. Plat. I, 3, p. 15, 1-9 Saffrey/Westerink). As Hermias’ and Proclus’ definitions of it as the ὕπαρξις of soul implies, the “One of the soul” is a principle pre-ontologically embedded within the soul (In Phaedr. 158, 24 – 159, 1; Procl. Theol. Plat. I, 3, p. 15, 1-6). Proclus holds that the One/First Principle is everywhere present, inasmuch as each being derives its existence from the gods (καθὸ τῶν ὄντων ἕκαστον ἐκ θεῶν ὑφέστηκε), and even though they proceed forth from the gods, they have not gone out from them but rather are rooted in them (In Tim. I, 209, 21-24 Diehl). Hermias almost verbatim maintains that, inasmuch as it derives from the gods, the soul owns a ἕν (καθὸ μὲν οὖν ἐκ θεῶν ὑφίσταται, ἔχει τὸ ἓν). Accordingly, he continues by saying that, inasmuch as it derives from the Intellect, the soul possesses a νοερόν (In Phaedr. 89, 1-10). Against this backdrop, union transcends vision, yet vision remains an essential and preparatory stage of the ascent. True union unfolds when Eros draws the soul into itself, gathering it at the point where it has stripped away all but its “One”—its deepest, most divine core—allowing it to exist solely in its ὕπαρξις.
Overall, by analysing the closely interconnected notions of “vision,” “experience,” and “union” in relation to the two highest "components" of the soul—intellect and “One”—this paper demonstrates that, for later Neoplatonists, the vision of the divine, which is dependent on the purification of the soul’s intellect, is a necessary yet insufficient stage in the ascent. The paper thus challenges the common assumption that the intellective vision of the divine is the apex of the religious experience. Instead, by shedding light on the relationship between Neoplatonic epistemology, metaphysics, ritual, and doctrine of the soul, it argues that the ascent can be considered complete (albeit temporarily) only when vision transitions into actual union with its object—a direct experience of the divine that is not merely intellective but rooted in the divine fragment embedded within the soul.
This paper examines the distinction between vision and union in later Neoplatonism, particularly in the works of Iamblichus, Hermias, and Proclus. While the vision of the divine is traditionally considered the highest religious experience, later Neoplatonists argued that it remains an intellective act and, as such, is insufficient for true union with the divine. Instead, they proposed that genuine union transcends intellect and is realized through theurgy—a ritual practice that activates a distinct "part" of the soul, the “One of the soul.” By analysing the metaphysical and epistemological framework of later Neoplatonism, this paper challenges the assumption that divine vision represents the ultimate stage of religious ascent. In doing so, it sheds new light on the role of theurgy as a transformative process that not only surpasses intellectual contemplation but also reconfigures the relationship between human and divine activity.