Before turning to the reduction itself, it is useful to further contextualize Plotinus’s notion of ascent. Ἀνάβασις represents both a development of a prior philosophical tradition as well as a crucial solution to aporiai specific to Plotinus’s methodology. Thus, in order to arrive at a fuller account of ascent, it is necessary to situate it within both contexts.
With respect to the first, it is important to stress that noetic reduction is a development of ideas found in Parmenides, Plato, and Aristotle. While Plotinus may have been the first to systematize the notion of ἀνάβασις, its foundations for were laid much earlier. Most generally, Plotinian ascent is the product of tradition that believes in the intelligibility of being. Very roughly, this doctrine claims that mind and being stand in a special relation to one another, indeed that they are inseperable ‘moments’ for each other.
Appreciating Plotinus’s contribution to this tradition requires a brief summation of its development. The origin of this tradition is arguably Parmenides’s famous fragment “τὸ γὰρ αὐτὸ νοεῖν ἐστίν τε καὶ εἶναι.” By the time of Plato and Aristotle, this concept was developed along a variety of metaphysical, psychological, and ethical lines. Expressions of this insight are apparent in Plato’s notion of the Good that renders beings ‘knowable,’ Aristotle’s doctrine that material beings are intelligible in potency, and their shared view that language and thought are always of being.
For a more precise articulation of this doctrine, one should look ‘downstream’ in the tradition. A particularly pure distillation is found in the scholastic dictum ens et res et verum convertuntur. That is, the intelligibility of being amounts to saying that being, thinghood, and truth are convertible. Insofar as something is, it must also be something definite, a hoc aliquid or a τόδε τι. Insofar as being is definite, it must be proportioned to the mind. A being is a ‘this’ or a ‘that,’ but not both at the same time and in the same respect. Therefore, if being is definite, then it will eo ipso be oriented to judgement. This conversion thus entails that being is always and everywhere proportioned and oriented to the mind and its faculties.
Plotinus’s doctrine of ascent clearly stands in this Parmenidian tradition. More specifically, it is a development of Plato’s and Aristotle’s view that truth exists in the intellect. This proposition can be understood in two senses. First, truth exists in the mind insofar as it thinks propositions adequate to the way things are in the world. Since definite being is ordered to judgement, and as judgement must be true or false, it follows that truth and falsehood must exist in a mind whose judgements correctly display or correspond to things.
However, one might question how such judgement, especially true judgement is possible. On a moment’s reflection, such a phenomenon is indeed remarkable. How is it possible that mind correctly combines and separates terms so as to think or say something true? What is the condition for the possibility of true judgement?
The conditions for its possibility must explain how one knows to combine and separate these terms in accordance with their significations. It must explain how the mind combines things in accordance with the ‘what it is to be’ of each thing. Consider the following syllogism:
(1) All men are mortal things
(2) All mortal things are corruptible things
∴ All men are corruptible things
Unless I know the meaning of these terms (i.e men, mortal, and corruptible), then I would not be able to recognize the truth of either the deduction as a whole or propositions themselves. Such signs words may as well be written in a foreign language. Though intelligible in themselves, they could never be true for me.
The recognition of truth presupposes prior meaning. One must not only know how certain terms are used, as even a blind man could use words correctly with respect to color, but also the things signified by such words. For instance, one must grasp what is signified by the term ‘mortal,’ the mortality by which mortal things are mortal. Recognizing the truth of language presupposes that I understand the ‘what it is to be’ of each term in question.
This understanding leads to the second sense in which truth is in the intellect. This sense is not so much about propositions, but about how the mind grasps of the meaning of singular terms, concepts, and things. In a word, truth is present when the intellect grasps simples, what Aristotle calls ἁπλᾶ, ἀσύνθετα, and ἀδιαίρετα.
Grasping this sense of truth’s presence in the intellect requires distinguishing simples as they exist in the mind from the way they exist in speech. With respect to mind, simples are discrete, and immaterial concepts, what Aristotle calls νοήματα in III.6 of De Anima. Νοήματα are units that the mind synthesizes and divides when it makes judgements about states of affairs. Aristotle does not say much about such beings or their origin, apart from some obscure remarks in III.5 and his claim in the beginning of De Interpretatione that they are passions in the soul (παθήματα τῆς ψυχῆς), which are themselves likenesses of things in the world (ὁμοιώματα πραγμάτων). Taking what little he does say into account, one could say that a νόημα is a passion of the soul and a likeness of beings by which the mind judges things in the world.
Insofar as simples are present in speech, they exist as atomic nouns and verbs. Such things vary according to culture and history. Their mode of being is thus different from and dependent on τὰ παθήματα τῆς ψυχῆς. Simples in speech are ultimately signs of simple passions in the soul, which, like things themselves, do not differ by time and place.
Having made this distinction, one can see how truth exists in the intellect by means of simples by attending to Aristotle’s own examples. He gives the simples ‘man’ and ‘white.’ These exist either as ὀνόματα ἐν τῇ φωνῇ or as νοήματα ἐν τῇ ψυχῇ. As stated above, their modes of being are different insofar as simples in speech vary while simples qua passions do not.
Despite this difference, however, these simples are alike in an important respect. Neither is able to signify true or false states of affairs. ‘White’ and ‘man,’ when said or thought alone cannot be true nor false. By contrast, the proposition ‘the man is white’ must be one or the other.
Hence, if truth is present in the intellect through simples, it is not the truth of judgement (ὀρθότης). On the contrary, this sense of truth is itself presupposes and is founded upon some prior sense of truth, θιγγάνειν or the mind’s ability to touch the ‘what it is to be’ signified by means of simples. Both kinds of truth exist in the mind, though the latter is clearly more fundamental than the former.
The diffence between ὀρθότης and θιγγάνειν is most apparent in their contraries. According to the first sense, truth is opposed to falsehood. A judgment must be either correct or incorrect, true or false. According to the second, though, truth is opposed to ignorance. One either grasps the ‘what it is to be’ of some term or does not. The opposite of τὸ ἀληθές is thus not τὸ ψεῦδος but ἄγνοια.
Truth in the second sense presupposes that mind experiences (πάσχειν) and somehow becomes one with the beings in question. When Aristotle says that mind “becomes all things” (πάντα γενέσθαι), part of what this means is that mind receives the forms and grasps the ‘what it is to be’ of beings. It is this grasp that distinguishes a man who can see from a blind man insofar as they both say things about color. They may say the same thing (e.g. that yellow is lighter than brown), but only the latter recognizes the truth of the proposition. The blind man simply accepts it on authority. The difference between the two presupposes that truth exists in the intellect in a way beyond correct judgement. Truth must imply some contact with the world or a kind of suffering with respect to things that makes any subsequent judgement possible.
With this background in place, it seems that Plotinian ἀνάβασις presupposes and develops both senses of truth’s presence in mind. With respect to the first, reduction assumes the truth of discursive judgement. Unlike Aristotle, Plotinus is not overly vexed by the vegetable-like man (ὁ ὅμοιος φυτῷ) of Γ.4 who denies the possibility of discursive judgement (i.e. that one could even say something as simple as ‘this is that’). Rather, he usually assumes that there is some knowledge of being and that discursive judgements testify to this knowledge. Sometimes he even dismisses certain theories on the grounds that, if true, they would render thinking and knowing impossible. It is as if the ensuing skepticism and inability to know being were sufficient grounds for rejecting such views. This abrupt treatment suggests that, for Plotinus, some knowledge of beings should be taken for granted and that this knowledge has something to do with διάνοια.
When one inquires into how such judgement is possible, one reverts to and discovers an immaterial place of forms within the mind, what Aristotle approvingly calls the τόπος εἴδων. Reduction proceeds by examining the truth of things as it unfolds within this peculiar and immaterial place, this ἄτοπος τόπος in the soul. Once the truth of being becomes manifest and the mind moves from potency to act, Plotinus tries to lay bare the original conditions that made truth possible in the first place. These conditions are intelligible and immaterial ἐνέργειαι in whose life and being finite mind ultimately participates.