[4.12.3] Robert Kilwardby on Syllogistic Form and Matter

Robert Kilwardby (ca. 1215–1279 AD), in his commentary to Aristotle’s “Prior Analytics commentary,” enriches the Arostotelian logic (see [1.3.9]) with a few new perspectives:

  • He applies the theory of four causes (see [1.3.4]) on syllogism and concludes that syllogisms, like any other objects, have material, formal, efficient, and final causes.
  • Syllogisms have matter (the premises and terms) and form (the mood and figure), thus presenting a hylomorphic structure (see [1.3.5])

The following  OntoUML diagram presents the main elements of Kilwarby’s hylomorphic syllogism:

Kilwardby on syllogistic matter and form
ClassDescriptionRelations
Syllogism“A syllogism is composed of form as well as matter.23 In elaborating
on this idea, Kilwardby applies the Aristotelian doctrine of causes to the syllogism.” (Thom, 2013)
A syllogism is an “inference with two premises, each of which is a categorical sentence, having exactly one term in common, and having as conclusion a categorical sentence the terms of which are just those two terms not shared by the premises”. (Smith, 2018)
Not all the triplets of two premises and one conclusion of the required structure are syllogisms, only just those who lead to a valid inference, listed in the moods.
E.g. P1: All man are mortal. P2: Socrates is man, C: Socrates is mortal.
has Form; has Matter; relates 2 Premises with 1 Conclusion; produces KnowledgeOrBelief
PropositionPropositions (assertion, apophanseis) are sentences with a specific structure: “every such sentence must have the same structure: it must contain a subject and a predicate and must either affirm or deny the predicate of the subject.” (Smith, 2018)
Term“Subjects and predicates of assertions are terms (horos) which can be either individual, e.g. Socrates, or universal, e.g. human. Subjects may be individual or universal, but predicates can only be universals.”(Smith, 2018)shared part of Proposition
PremiseA possible role of an Proposition, relative to a Syllogism is Premise (protasis).
E.g. P1: All man are mortal. P2: Socrates is man.
in material relation with Conclusion; role of Proposition
MajorPremise“The major premise occupies a determining role, since it is ‘contracted’ by the minor premise to produce the conclusion. Because of this relation between major and minor premise, Kilwardby reasons, the minor should not be counted along with the major; and so, he says, the Aristotelian definition of the syllogism rightly names oratio (in the singular) as its genus, not orationes.” (Thom, 2013)
E.g. P1: All man are mortal.
subkind of Premise
MinorPremise“The major premise occupies a determining role, since it is ‘contracted’ by the minor premise to produce the conclusion. (Thom, 2013)
E.g. P2: Socrates is man.
subkind of Premise
ConclusionA possible role of an Proposition, relative to an Syllogism is Conclusion (sumperasma).
E.g. C: Socrates is mortal.
role of Proposition
Figure“The middle term must be either subject or predicate of each premise, and this can occur in three ways: the middle term can be the subject of one premise and the predicate of the other, the predicate of both premises, or the subject of both premises. Aristotle refers to these term arrangements as figures (schêmata)”. (Smith, 2018)
There are 3 Figures.
characterizes Syllogism
MoodMood characterizes a syllogism, and is prooved with a Proof. There are 14 Moods, 4 for the First figure, 4 for the Second figure, and 6 fot the Third figure.characterizes Syllogism
MatterThe matter of the syllogism “consists of two propositions (the
major and minor premises) and three terms. It is worth noting that on Kilwardby’s account, the syllogism is materially constituted by two propositions, not three. The conclusion is not part of the syllogism; therefore, the syllogism is not a type of consequence. The syllogism’s two premises, however, possessa unity thanks to the fact that they aim at a single conclusion.” (Thom, 2013)
E.g. matter in this example:
Major premise: All man are mortal.
Minor PremiseSocrates is man
Terms: man, mortal, Socrates
is MaterialCause; generalizes Premise and Term
Form“A syllogism’s form is the figure and mood as shown respectively by the relative position of the terms in the premises and by the premises’ quality and quantity; this is indicated by Aristotle when he says that in the syllogism certain things are posited (positis).”is FormalCause; generalizes Mood and Figure
Knowledge
OrBelief
“The demonstrative and dialectical syllogism also have a final cause, namely, the production respectively of knowledge or belief.” (Thom, 2013)is FinalCause
HumanHumanproduces Syllogism; is EfficientCause
Cause“Aristotle places the following crucial condition on proper knowledge: we think we have knowledge of a thing only when we have grasped its cause (aitia).” (Falcon, 2019)
MaterialCause“The material cause: ‘that out of which’, e.g., the bronze of a statue. […]
The bronze enters in the explanation of the production of the statue as the material cause. Note that the bronze is not only the material out of which the statue is made; it is also the subject of change, that is, the thing that undergoes the change and results in a statue. The bronze is melted and poured in order to acquire a new shape, the shape of the statue.” (Falcon, 2019)
subkind of Cause
FinalCause“The final cause: ‘the end, that for the sake of which a thing is done’, e.g., health is the end of walking, losing weight, purging, drugs, and surgical tools.” (Falcon, 2019)subkind of Cause
EfficientCause“the actual syllogisms that people produce have efficient causes.” (Thom, 2013))
“The efficient cause: ‘the primary source of the change or rest’, e.g., the artisan, the art of bronze-casting the statue, the man who gives advice, the father of the child.” (Falcon, 2019)
subkind of Cause
FormalCauseFormal cause, or the expression of what it is”, e.g., the shape of a statue. […]
The bronze is melted and poured in order to acquire a new shape, the shape of the statue. This shape enters in the explanation of the production of the statue as the formal cause.” (Falcon, 2019)
subkind of Cause

Sources

  • Thom, Paul, “Robert Kilwardby on the Syllogistic Form”, A Companion to the Philosophy of Robert Kilwardby, Christopher Henrik Lagerlund and Paul Thom (ed), Brill, 2013
  • Falcon, Andrea, “Aristotle on Causality“, The Stanford Encyclopedia of Philosophy (Spring 2019 Edition), Edward N. Zalta (ed.)
  • Smith, Robin, “Aristotle’s Logic“, The Stanford Encyclopedia of Philosophy (Winter 2018 Edition), Edward N. Zalta (ed.)
  • Silva, José Filipe, “Robert Kilwardby“, The Stanford Encyclopedia of Philosophy (Winter 2016 Edition), Edward N. Zalta (ed.)

First published: 11/2/2021

[4.12.2] Robert Kilwardby on Active Sense Perception and Cognition

Robert Kilwardby (ca. 1215–1279 AD), in De spiritu fantastico discusses the structure of the human soul and the process which leads from sense perception to cognition:

  • He sustains that the human soul is a composite of three forms: the vegetative (common in all living beings), sensitive (present in animals and humans), and intellective (specific to humans) (see also [4.12.1])
  • The powers of the sensitive soul are common sense, sensitive memory, while intellectual memory, intellect, and will are the intellective soul’s powers.
  • There is no knowledge of sensible objects without prior use of the senses, because the soul is completely empty before sensation.
  • The object present to the sense organ generates sensible species in the medium, which then changes the sense organ. For example, in the case of sight, the medium must be transparent, there must be light, and the object should be in the front of the eye.
  • The sense organ passively receives the sensible species from the objects of the surrounding environment, while the sensitive soul actively directs the attention on some of the sensible species; this is when perception occurs. Soul, through the act of attention, acts upon and controls the sense organ and not vice-versa.
  • Imagination creates images even than the object is not present; intellect abstracts universals from many images.

The following UML Use Case diagram presents Kilwarby’s model of the human soul:

Kilwardby on sense perception and cognition
PowerRelated use caseRelations
Sense organSENSE organ is passively impressed by the sensible species of the object: “The affection of the sense organ (affectio organi) by the sensible species irradiated from the sensible object (ab obiecto sensibili). The result of this motion is the impression of the sensible species in the sense organ.” (Silva, 2013)
Common sense(Common sense) percepts likenesses of sensible species and apprehends the present object: “The soul involves itself with the species received in the sense organ (conuoluendo se cum illa), which results in the production by the soul of an image or likeness (similitudo) of the sensible species. According to Kilwardby, the sensory soul forms the image by natural instinct (instinctu naturali). Perception is possible due to the soul’s intentional state with respect to the affection of the organ. When human beings sleep, the sense organs continue to be impressed by the species from sense objects; however, this impression, without the attention of the soul, does not give rise to any act of perception. The sensory soul turns upon itself and sees itself as being similar (reflectendo aciei uidet se talem) to the species of the sensible object. When the soul turns its eye upon itself, the soul sees the sensible object through the image made by itself in and from itself. […]
The object is the necessary occasion and the causa sine qua non (otherwise there would be nothing to be perceived) but not the sufficient cause of perception (DSF 103; 123). The efficient cause per se of perception is the immaterial soul—the division into sensory faculties is instrumental to the process and in most of this part of the treatise Kilwardby talks of the operations of the sensory soul (which he also calls the ‘incorporeal sensitive spirit’) as a unified entity. spiritus sensitivus thing. The image in the soul is not the same as the one in the sense organ.” (Silva, 2013)
includes “SENSE organ is passively impressed by the sensible species of the object
SENSITIVE SOULSENSITIVE SOUL is intentionally attentive to objectincludes “(Common sense) percepts likenesses of sensible species and apprehends the present object
Sensory memory(Sensory memory) retains images: “Kilwardby argues that the power of memory is responsible for receiving the images of objects of knowledge by natural assimilation, for preserving the images of sensible objects, and for making them available for the powers of imagination” (Silva, 2016)includes “(Common sense) percepts likenesses of sensible species and apprehends the present object
Imagination(Imagination) creates images when object is not presentincludes “(Sensory memory) retains images
Intellectual memory(Intellectual memory) retains images: “Kilwardby argues that the power of memory is responsible for receiving the images of objects of knowledge by natural assimilation, for preserving the images of sensible objects, and for making them available for […] intellect” (Silva, 2016)includes “(Imagination) creates images when object is not present
IntellectIntellect abstracts universals as the common part of the multitude of images: “The universal is reached by the intellect considering that which is common (the ratio uniuersalis or ratio commune) to the multitude of images (or likenesses or phantasms or species) of sensible things (corporalia) retained by memory, without the particular circumstances of the images. […]
Scientific knowledge is certain and necessary because it is about what always is (De ortu scientiarum 47, 437–38). There is no science of individual sensible things existing here and now (hic et nunc), but only of universals. However, there is a continuity between the knowledge of images of particular objects in imagination and universals abstracted from them (the cognition of the former is directed to the cognition of the latter).” (Silva, 2013)
includes “(Intellectual memory) retains imagest
WillWill initiates action

Sources

  • Silva, José Filipe, “Robert Kilwardby“, The Stanford Encyclopedia of Philosophy (Winter 2016 Edition), Edward N. Zalta (ed.)
  • Silva, José Filipe, “Robert Kilwardby on the Theory of the Soul and Epistemology”, A Companion to the Philosophy of Robert Kilwardby, Christopher Henrik Lagerlund and Paul Thom (ed), Brill, 2013
  • J.F. Silva & J. Toivanen, “The Active Nature of the Soul,” Vivarium 48 (2010): 245–278.

First published: 4/2/2021
Updated: 14/3/2021