Main article: Active Intellect

The active intellect was a concept Aristotle described that requires an understanding of the actuality-potentiality dichotomy. Aristotle described this in his De Anima (book 3, ch. 5, 430a10-25) and covered similar ground in his Metaphysics (book 12, ch.7-10). The following is from the De Anima, translated by Joe Sachs, ^[28] with some parenthetic notes about the Greek. The passage tries to explain "how the human intellect passes from its original state, in which it does not think, to a subsequent state, in which it does." He inferred that the energeia/dunamis distinction must also exist in the soul itself: ^[29] -

...since in nature one thing is the material [ hulē ] for each kind [ genos ] (this is what is in potency all the particular things of that kind) but it is something else that is the causal and productive thing by which all of them are formed, as is the case with an art in relation to its material, it is necessary in the soul [ psuchē ] too that these distinct aspects be present;

the one sort is intellect [ nous ] by becoming all things, the other sort by forming all things, in the way an active condition [ hexis ] like light too makes the colors that are in potency be at work as colors [to ph ō spoiei ta dunamei ontachr ō mata energeiai chr ō mata ].

This sort of intellect is separate, as well as being without attributes and unmixed, since it is by its thinghood a being-at-work, for what acts is always distinguished in stature above what is acted upon, as a governing source is above the material it works on.

Knowledge [epist ē m ē ], in its being-at-work, is the same as the thing it knows, and while knowledge in potency comes first in time in any one knower, in the whole of things it does not take precedence even in time.

This does not mean that at one time it thinks but at another time it does not think, but when separated it is just exactly what it is, and this alone is deathless and everlasting (though we have no memory, because this sort of intellect is not acted upon, while the sort that is acted upon is destructible), and without this nothing thinks.

This has been referred to as one of "the most intensely studied sentences in the history of philosophy". ^[29] In the Metaphysics, Aristotle wrote at more length on a similar subject and is often understood to have equated the active intellect with being the " unmoved mover " and God. Nevertheless, as Davidson remarks:

Just what Aristotle meant by potential intellect and active intellect – terms not even explicit in the De anima and at best implied – and just how he understood the interaction between them remains moot to this day. Students of the history of philosophy continue to debate Aristotle's intent, particularly the question whether he considered the active intellect to be an aspect of the human soul or an entity existing independently of man. ^[29]

Post-Aristotelian usage[ edit ]

New meanings of energeia or energy [ edit ]

Already in Aristotle's own works, the concept of a distinction between energeia and dunamis was used in many ways, for example to describe the way striking metaphors work, ^[30] or human happiness. Polybius about 150 BC, in his work the Histories uses Aristotle's word energeia in both an Aristotelian way and also to describe the "clarity and vividness" of things. ^[31] DiodorusSiculus in 60-30 BC used the term in a very similar way to Polybius. HoweverDiodorus uses the term to denote qualities unique to individuals. Using the term in ways that could translated as 'vigor' or ' energy ' (in a more modern sense); for society, 'practice' or 'custom'; for a thing, 'operation' or 'working'; like vigor in action. ^[32]

Platonism and neoplatonism [ edit ]

Already in Plato it is found implicitly the notion of potency and act in his cosmological presentation of becoming (kin ē sis) and forces (dunamis), ^[33] linked to the ordering intellect, mainly in the description of the Demiurge and the "Receptacle" in his Timaeus. ^{[34] [35]} It has also been associated to the dyad of Plato's unwritten doctrines, ^[36] and is involved in the question of being and non-being since from the pre-socratics, ^[37] as in Heraclitus 's mobilism and Parmenides ' immobilism. The mythological concept of primordial Chaos is also classically associated with a disordered prime matter (see also prima materia), which, being passive and full of potentialities, would be ordered in actual forms, as can be seen in Neoplatonism, especially in Plutarch, Plotinus, and among the Church Fathers, ^[37] and the subsequent medieval and Renaissance philosophy, as in Ramon Lllull 's Book of Chaos ^[38] and John Milton 's Paradise Lost. ^[39]

Plotinus was a late classical pagan philosopher and theologian whose monotheistic re-workings of Plato and Aristotle were influential amongst early Christian theologians. In his Enneads he sought to reconcile ideas of Aristotle and Plato together with a form of monotheism, that used three fundamental metaphysical principles, which were conceived of in terms consistent with Aristotle's energeia/dunamis dichotomy, and one interpretation of his concept of the Active Intellect (discussed above):-

• The Monad or "the One" sometimes also described as " the Good ". Thisisthe dunamis orpossibilityofexistence.
• The Intellect, or Intelligence, or, to use the Greek term, Nous, which is described as God, or a Demiurge. It thinks its own contents, which are thoughts, equated to the Platonic ideas or forms (eide). The thinking of this Intellect is the highest activity of life. The actualization of this thinking is the being of the forms. This Intellect is the first principle or foundation of existence. The One is prior to it, but not in the sense that a normal cause is prior to an effect, but instead Intellect is called an emanation of the One. The One is the possibility of this foundation of existence.
• Soul or, to use the Greek term, psyche. The soul is also an energeia: it acts upon or actualizes its own thoughts and creates "a separate, material cosmos that is the living image of the spiritual or noetic Cosmos contained as a unified thought within the Intelligence".

This was based largely upon Plotinus' reading of Plato, but also incorporated many Aristotelian concepts, including the unmoved mover as energeia. ^[40]

New Testament usage [ edit ]

Other than incorporation of Neoplatonic into Christendom by early Christian theologians such as St. Augustine, the concepts of dunamis and ergon (the morphological root of energeia ^[41]) are frequently used in the original Greek New Testament. ^[42] Dunamis is used 116 times ^[43] and ergon is used 161 times, ^[44] usually with the meaning 'power/ability' and 'act/work', respectively.

Essence-energies debate in medieval Christian theology [ edit ]