I quote Lloyd Gerson and Christian Wildberg from the Stanford Encyclopedia of Philosophy, who both point to the immeasurable significance of Plotinus. In my thesis I argue for a developmental continuum from Plotinus via Hegel to Marx who ‘inverted’ that mystical current and stood it on its material feet. Where Marx had no interest in mysticism other than recognising it in Hegel’s philosophy, once this continuum has been acknowledged, it can be mined – particularly its weaknesses – to further develop dialectical materialism.
Porphyry’s edition of Plotinus’ Enneads preserved for posterity the works of the leading Platonic interpreter of antiquity. Through these works as well as through the writings of Porphyry himself (234 – c. 305 C.E.) and Iamblichus (c. 245–325 C.E.), Plotinus shaped the entire subsequent history of philosophy. Until well into the 19th century, Platonism was in large part understood, appropriated or rejected based on its Plotinian expression and in adumbrations of this.
The theological traditions of Christianity, Islam, and Judaism all, in their formative periods, looked to ancient Greek philosophy for the language and arguments with which to articulate their religious visions. For all of these, Platonism expressed the philosophy that seemed closest to their own theologies. Plotinus was the principal source for their understanding of Platonism.
Through the Latin translation of Plotinus by Marsilio Ficino published in 1492, Plotinus became available to the West. The first English translation, by Thomas Taylor, appeared in the late 18th century. Plotinus was, once again, recognized as the most authoritative interpreter of Platonism. In the writings of the Italian Renaissance philosophers, the 15th and 16th century humanists John Colet, Erasmus of Rotterdam, and Thomas More, the 17th century Cambridge Platonists, and German idealists, especially Hegel, Plotinus’ thought was the (sometimes unacknowledged) basis for opposition to the competing and increasingly influential tradition of scientific philosophy. This influence continued in the 20th century flowering of Christian imaginative literature in England, including the works of C.S. Lewis and Charles Williams.
Lloyd Gerson, ‘Plotinus,’ Stanford Encyclopedia of Philosophy
It is an undeniable fact, although nowadays rarely acknowledged, that the general outlook and the principal doctrines of the Neoplatonists proved exceedingly influential throughout the entire history of western philosophy. Through Augustine (354–430) in the West and the 4th-century Cappadocian Fathers (Basil, Gregory of Nyssa, Gregory of Nazianzus) in the East as well as the pseudo-epigraphic writings of Dionysius the Areopagite (early 6th century), Neoplatonism profoundly influenced the emergence of mainstream and not so mainstream Christian theology (John Scotus Eriugena, Thomas Aquinas, Duns Scotus, Meister Eckhart). In addition, by way of a pseudo-epigraphical treatise entitled Theology of Aristotle, Neoplatonic thought facilitated the integration of ancient philosophy and science into both Islam (especially through Al-Kindi, Al-Farabi and Avicenna [Ibn Sina]) and Judaism (Maimonides).
…It may even be true to say that even more than the writings of Plato and Aristotle themselves Neoplatonic ideas have continued to influence Western thinkers of the idealist persuasion, such as the Cambridge Platonists (who were really Neoplatonists), Leibniz, Hegel, Schelling, Fichte, Bergson and Teilhard de Chardin, to name but a few.
…Perhaps another reason that this kind of thinking strikes the general public as arcane and alien may that the Abrahamic religions, even if they too posit a single divine principle as the source of all being, conceive of this principle as a person and maker. This vestige of pre-philosophical anthropomorphism bypasses the difficult questions that the last pagan thinkers so arduously struggled to answer when they sought to explain the existence of the diverse and complex physical world from a non-material principle that they assumed to be nothing but One.
Christian Wildberg ‘Neoplatonism,’ Stanford Encyclopedia of Philosophy