[3.2.3] Al-Farabi on Knowledge and Certitude

An important concept related to knowledge in al- Fārābī’s (872-950 AD)(and arabic) philosophy is certitude (al-yaqīn): “‘Certitude’ is identified as the cognitive state produced in the knower by her employment of demonstrative methods, in contrast to the inferior logical arts of dialectic, rhetoric, poetics, and sophistry, which produce cognitive states that approximate the certitude of demonstration in varying degrees. “Certitude” thus functions as a technical term in Arabic accounts of demonstration, to a large extent displacing the traditional identification of the end of demonstration as the production of “knowledge” or “science” (‘ilm, equivalent to the Greek epistēmē).”

Al-Fārābī writes about the notion of absolute certainty in his Book of Demonstration (Kitāb al-burhān) and the second is the Book on the Conditions of Certitude (Kitāb Šara’iṭ al-yaqīn). Here Al-Farabi names six, more and more restrictive criteria, the fulfillment of which lead to absolute certitude. These can be conceptualized as the differentia in the 10-fold Aristotelian categorization scheme [1.3.2].

The six criteria are:

  • second order knowledge criteria: (C1) S believes that p; (C2) p is true; (C3) S knows that p is true;
  • certitude criteria: (C4) it is impossible that p not be true; (C5) there is no time at which p can be false; (C6) conditions 1-5 hold essentially, not accidentally;

The process of getting to absolute certitude is shown in the UML Activity Diagram below, where S is the subject and p is the proposition:

Al-Farabi on knowledge and certidude

By the end of this process the potentiality in Material Intellect becomes actualized in the Actual Intellect by grasping absolute certitude (see [32] also).


First published: 24/07/2019

[3.2.2] Al-Farabi on Soul and Intellect

Al-Farabi’s (872-950 AD) views on the human soul and intellect can be found spread through some of its works: The Political Regime (Kitāb al-siyāsa al-madaniyya), The Principles and Opinions of the People of the Virtuous City (Mabādi’ ārā’ ahl al-madīnah al-fāḍilah), and The Treatise on the Intellect (Risālah fi’l-‘aql).

His thoughts about the human soul:

  • are heavily influenced by Aristotle’s views on soul [1.3.6], and its theory of hylomorphism (material intellect – actual intellect – form) [1.3.5], [1.3.7];
  • can be understood in the light of his cosmology [3.2.1];
  • explain prophecy, as a phenomenon.

The following UML Use Case diagram presents al-Farabi’s view on the human soul:

al-Farabi on the soul
FacultyRelated Use Case
NUTRITIONUse NUTRITION: to feed the human body. Nutrition is a faculty present in all living bodies, namely plants, non-rational animals and rational animals.
REPRODUCTIONUse REPRODUCTION: to create new human bodies. Reproduction is a faculty present in all living bodies, namely plants, non-rational animals and rational animals.
PERCEPTION Use TASTE, TOUCH, SMELL, HEAR, SEE perception: are shared by non-rational and rational animals.
APPETITEExperience desire/aversion through APPETITIVE faculty: “through which humans and animals experience desire or aversion towards the objects they perceive through the senses”
IMAGINATIONUse IMAGINATION to retain and combine sensations/perceptions; prophecy: “… its function is to retain sense impressions when they are no longer perceived as external stimuli, and also to combine, compose, and even reproduce, those impressions. Following the Aristotelian account, al-Fārābī thinks that the imaginative faculty is intermediate between the sensitive and rational faculties…
The highest rank of perfection that the imaginative faculty can achieve is precisely when an individual attains prophecy or awareness of present or future events, as well as the capacity to see glorious or divine beings. This can be achieved by means of present and future particulars and the transcendent intelligibles of divine beings, both granted by the active intellect.”
Imagination works both in the waking and the sleeping sate of the soul.
HUMAN INTELLECT (RATIONAL)Material Intellect rules other faculties & functions; has potential to abstract forms: “In The Treatise on the Intellect al-Fārābī refers to the material intellect (νοῦς ὑλικὸς, a Greek term coined by Alexander) as a soul or part of the soul, or one of the faculties of the soul, or something that is in potency to abstract the forms from their matter and turning these into forms for itself”
HUMAN INTELLECT (RATIONAL)Use Theoretical rationality to comprehend unalterable things: “In its theoretical aspect, the rational faculty allows humans to attain the knowledge of things that are in a certain way and cannot be otherwise; that is, humans are not able to act upon them or alter them. For example, we cannot do anything to alter the fact that three is an odd number and four an even number.”
HUMAN INTELLECT (RATIONAL)Use Practical rationality to alter things: “in its practical aspect, the rational faculty deals with those things humans can act upon and alter. In this practical dimension, the rational faculty involves skills and calculation. Skills refer to acquired abilities for practicing activities such as carpentry, farming, medicine, or sailing, while calculation is related to those situations where we need to deliberate about something we want to do, when we want to do it, whether it is possible to do it and, if possible, how it should be done.”
HUMAN INTELLECT (RATIONAL)Actual Intellect grasps Forms of external objects: “In The Treatise on the Intellect al-Fārābī refers to the material intellect (νοῦς ὑλικὸς, a Greek term coined by Alexander)… that is in potency to abstract the forms from their matter and turning these into forms for itself. When these forms are abstracted, they become intelligibles or forms for the material intellect. It can be rightly said that for al-Fārābī the material intellect is like the matter where the abstracted forms come to be, where the material intellect itself becomes the abstracted forms, just as the imprinted object leaves its mark on a piece of wax.
Before a form of the objects outside the soul has been abstracted, the material intellect is just in potency to receive those forms or potential intelligibles; but when these latter come to be in the material intellect, the material intellect becomes an actual intellect, and the potential intelligibles are actualized.”
HUMAN INTELLECT (RATIONAL)Acquired Intellect grasps forms of higher, supralunary things, with the help of Active Intellect: “Since the actual intellect becomes itself the actual intelligibles, then they are one and the same thing: what is understood is not different from the intellect itself, since the actual intelligible has become the form of the actual intellect. If other intelligibles come to be in the actual intellect, they will also be actualized. As a consequence, the actual intellect will be able to understand on its own and not by means of forms in matter outside from itself. When this stage of intellection is attained, the actual intellect becomes the so-called ‘acquired’ intellect.”


First published: 18/07/2019