[1.3.20] Aristotle on Passive and Active Intellect

Aristotle (384-322 BC) in De Anima distinguishes two aspects, roles of the incorporeal intellect (mind, see also [1.3.6], [1.3.7]) :

  • The passive intellect can potentially be anything by receiving that thing’s intelligible form.
  • The active intellect takes on the immaterial intelligible form through thinking.

The following OntoUML diagram shows Aristotle’s model of passive and active intellect:

Aristotle on passive and active intellect
ClassDescriptionRelations
MindIn De Anima III.4-5. “Aristotle gives an account of thinking (or intellect [mind]noêsis) that is modeled on his account of perception in Book II. Just as in perception, ‘that which perceives’ (to aisthêtikon) takes on sensible form (without matter), so in thinking ‘that which thinks’ (to noêtikon) takes on intelligible form (without matter). Similarly, just as in perception, the perceiver has the quality of the object potentially, but not actually, so, too, in understanding, the intellect is potentially (although not actually) each of its objects. […]
‘intellect understands all things’ (nous panta noei, 429a19). Not only can you think about the objects of perception (colors, odors, sounds, the son of Diares, etc.), but you can think about things that can’t be perceived at all (numbers, virtues, etc.), either intrinsically or coincidentally. You can think about anything. This universality of the objects of thought has several important consequences.

Intellect is ‘unmixed’
The first is that the intellect “must be unmixed,” i.e., must be pure potential (since it can think about anything, it must be only potentially that thing). So it has no nature of its own—if it did, it would be unable to think about that nature.

Intellect is separable, perception is bodily
‘It is unreasonable for intellect to be mixed with the body, since it would then acquire some quality (for instance, hot or cold) or even, like the perceiving part, have some organ, whereas in fact it has none. (42925-27)’
Since intellect does not have a bodily organ, it is separable from the body:
‘… intellect is separable, whereas the perceiving part requires a body. (429b5)'”
PassiveIntellect“Aristotle never actually uses the phrase nous pathêtikos (passive intellect), but the concept is clearly present in his account. We can reconstruct his argument as follows. It begins with the total passivity of an intellect that can ‘become all things.’
The passive intellect is potentially each of its objects, but not actually any of them. (429a16)
The passive intellect can think anything. (429a18)
Hence, the passive intellect is actually nothing until it thinks. (429a23)”
role of Mind
ActiveIntellect“The Active Intellect […] is something other than the passive intellect […] is the efficient cause of its thinking (i.e., of its taking on intelligible form). […]
Nous poiêtikos [active intellect] is thus not ‘mind’ but an aspect of the mind; an aspect of a person’s mental capacities. The characteristics that have led some to identify nous poiêtikos with God or with something divine are these. It is, Aristotle says:
‘separate, impassive, ever-active, immortal, eternal’
But these attributes can be construed more antiseptically. They are mostly features of the immateriality of nous poiêtikos. Being separate does not imply a possible pre- or post-embodiment existence: rather, it implies nothing more than irreducibility to anything material.”
role of Mind; in material relation with IntelligibleForm
IntelligibleFormThe active intellect, that which thinks’ (to noêtikon) takes on the immaterial intelligible form linked to the object of thought (noêton).
ThinkingThinking: “the active intellect makes things thinkable by making them actually thought-about.”relates IntelligibleForm with ActiveIntellect

Sources

First published: 1/7/2021
Updated: 8/12/2021

[1.3.6] Aristotle on the Soul and Mind

Aristotle (384-322 BC), in his work De Anima investigates the soul’s faculties and the relation between them. He sustains, that all living beings have soul, and constructs a hierarchical model of the types of souls: 

FacultyPlant’s soulAnimal soulHuman soul
Nutritionincludesincludesincludes
Reproductionincludesincludesincludes
Perceptionincludesincludes
Desireincludes
Imaginationincludes
Mind (intellect, nous)includes

“The reasons why this should be so are broadly teleological. In brief, every living creature as such grows, reaches maturity, and declines. Without a nutritive capacity, these activities would be impossible… So, Aristotle concludes, psychology must investigate not only perceiving and thinking, but also nutrition.”

The following UML Use Case diagram shows the main concepts in Aristotle’s philosophy of mind:

Aristotle on the soul and mind

Use cases:

FacultyUse CaseRelations
NUTRITIONUse NUTRITION (UC7): “Mind includes the non-human animal level sense-perception, which includes the plant level nutrition.”
REPRODUCTION Use REPRODUCTION (UC8): “… any creature with perception will also have the ability to take on nutrition and to reproduce
PERCEPTIONUse TASTE, TOUCH, SMELL, HEAR, SEE (UC1-UC5) perception to recieve sensible species: “Aristotle claims that [sense] perception is best understood on the model of hylomorphic change generally: just as a house changes from blue to white when acted upon by the agency of a painter applying paint, so ‘perception comes about with <an organ’s> being changed and affected… for it seems to be a kind of alteration’. So in line with his general account of alteration, Aristotle treats perception as a case of interaction between two suitable agents: objects capable of acting and capacities capable of being affected.”
Sensible species is the representation of the object in the sense-organs.
PERCEPTIONUse COMMON SENSE (koine aisthesis) to unify and monitor 5 senses (UC6)includes UC1-UC5, UC7, UC8
MIND (or intellect)Use MIND (intellect, nous) for knowing an understanding (UC9): Mind or intellect is a faculty posessed just by humans; it has 2 sub-types: Theoretical and Practical mind.
“Human minds do more than understand, however. It is equally essential to the human being to plan and deliberate, to ponder alternatives and strategize, and generally to chart courses of action.”
includes UC6, UC12, UC14
MIND (or intellect) Use THEORETICAL MIND (sophia): from experience grasps of first principles (ta próta); generate Knowledge (epistemê) (UC10)inherits from UC9
MIND (or intellect) Use PRACTICAL MIND (phronēsis) to initiate change (UC11): “desire and practical reason (De Anima iii 10, 433a17–19), though they do not work in isolation from one another. Rather, practical reason, broadly construed to incorporate the kind of image-processing present in non-human animals, is a source of movement when it focuses upon an object of desire as something desirable. So, practical reason and desire act corporately as the sources of purposive motion in all animals, both human and non-human (De Anima iii 10, 433a9–16), even though, ultimately, it is desire whose objects prick practical intellect and set it in motion (De Anima iii 10, 433a17–2).”inherits from UC9; includes UC15
MIND (or intellect) Use MEMORY for storing and recollection of images (UC13).
MIND (or intellect) Create Experience (empiria) (UC12):experience (empiria)—…a technical term in this connection, reflecting the point at which a single universal comes to take root in the mind” includes UC13
IMAGINATIONUse IMAGINATION (phantasia) to produce images (UC14): “Aristotle identifies imagination as ‘that in virtue of which an image occurs in us’, where this is evidently given a broad range of application to the activities involved in thoughts, dreams, and memories…”
Aristotle regards the images used in cognitive processes in two ways:
● as having its very form in the mind (conformity),
● a mental image in the mind that naturally resembles the object (resemblance). 
DESIREUse DESIRE (orektikon) to initiate motion (UC15): “Aristotle concludes, there is a faculty of desire whose activities and objects are primarily, if not autonomously or discretely, responsible for initiating end-directed motion in animals. What animals seek in action is some object of desire which is or seems to them to be good.”

Actors:

ACTORDESCRIPTIONRELATIONS
Object in External WorldAn object in the external world.UC1, UC2, UC3, UC4, UC5
User of the SoulA human person.uses UC10, UC11

Observations:

  • Aristotle in the analysis of the Soul uses the hylomorphic model (see in [1.3.5]) for explaining the unity of the body and soul, and the working mechanism of perception and mind.
  • All living things have Soul, as their Form. Hence the Human Soul encompasses the faculty of mind (reason), which includes the non-human animal level sense-perception, which includes the plant level nutrition. Mind, sense-perception, and nutrition are the differentia specifica in Aristotle’s 10-fold categorization (see in [1.3.2]).
  • The existence of the living things is teleological (see in [1.3.4]).

The following OntoUML diagram presents the main classes in Aristotle’s theory of soul:

Sources:

  • All citations and more about the topic in: Shields, Christopher, “Aristotle’s Psychology“, The Stanford Encyclopedia of Philosophy (Winter 2016 Edition), Edward N. Zalta (ed.)
  • Richard Sorabji, “Aristotle on demarcating the five senses”, Philosophical Review, 1971

First published: 11/4/2019
Updated: 16/4/2019: some use case relations changed
Updated: 27/4/2019: added 5 Senses and Common Sense
Updated: 14/7/2019: added reproduction
Updated: 10/8/2020
Updated: 8/6/2021
Updated: 30/11/2021 added OntoUML diagram