Seeing an object, keeping its image in mind, and recognizing what it means to you are different activities. Ibn Sina, known in Latin as Avicenna, developed an account of those differences. His work combines questions about perception with a larger question: what kind of thing is the self? (Gutas, “Ibn Sina,” §4).
His answer belongs to medieval philosophy. Understanding it requires keeping its unfamiliar parts alongside the ones that sound recognizable.
A life across several cities
Avicenna was born in Afshana, near Bukhara. His exact birth year is Unknown: the scholar Dimitri Gutas places it around 970, possibly earlier, rather than treating 980 as settled. He worked as a physician and adviser under several rulers, lived in places including Hamadan and Isfahan, and died in Hamadan in 1037 (Gutas, §1.1).
Our fullest life account combines Avicenna’s own account with a continuation by his companion and student al-Juzjani (Gutas, §1.1). It is an important source, but its presentation of intellectual achievement needs interpretation.
Avicenna also exchanged questions and answers with al-Biruni. That documented correspondence is a firmer description of their relationship than calling al-Biruni his teacher (Bosworth, “Biruni,” p. 1).
A “Healing” that is not a medical handbook
The Book of Healing, or al-Shifa, is an extensive work of philosophy and science. Its subjects include logic, natural philosophy, mathematics and metaphysics. Mathematics includes music, alongside arithmetic, geometry and astronomy. The discussion of soul belongs within natural philosophy (Gutas, §1.2).
It is distinct from Avicenna’s medical Canon. The titles should not be merged, and the Healing should not be read as a collection of treatments. Here we follow its questions about sensing and thinking.
Five jobs inside perception
Avicenna distinguishes the familiar external senses from internal senses. In a standard account, these perform five different jobs (Rahman, “Avicenna: Psychology,” pp. 2–3):
- Common sense brings together information from the external senses. Here the phrase means coordination, not everyday good judgment.
- Retentive imagination preserves an image after its object is absent.
- Combining imagination puts images together or separates them. An imagined golden mountain illustrates a combination.
- Estimation, or wahm, grasps a significance that is not simply a visible shape or color.
- Memory retains the meanings grasped through estimation.
These are Documented features of his historical account. The English names vary across translations, and “imagination” can refer to more than one job. Keeping an image is different from rearranging it.
The list is also more careful than calling the fifth faculty “intentions.” The meanings or “intentions” are what the faculty retains, not the faculty itself (Ivry, §4).
Why a sheep matters
The sheep and wolf provide a famous example. In Avicenna’s account, seeing the wolf’s appearance differs from grasping it as dangerous. He uses estimation to explain that second activity (Hasse, §5.1).
This is an example within his theory, not a controlled animal experiment. It separates the object’s sensory appearance from its significance for a perceiver. “Intention” in this context should not be read simply as a conscious plan.
Avicenna associates internal faculties with regions of the brain’s ventricles. Yet he also argues that the rational soul is immaterial. Those claims coexist in his system; attention to bodily organs does not mean he rejects an immaterial soul (Ivry, §4).
The floating person
A passage in the Healing asks the reader to imagine a person created all at once, suspended without sensory contact and with limbs apart. Avicenna proposes that this person would affirm their own existence without affirming awareness of their bodily parts (Soul I.1, paragraph 7).
The scenario is a thought experiment: an imagined case used in an argument. It was not a recorded experiment involving a real person. It directs attention to self-awareness and to Avicenna’s proposed distinction between self and body; it does not by itself establish a modern scientific finding.
Translation also brought disagreement
In twelfth-century Toledo, Dominicus Gundisalvi and Avendauth translated Avicenna’s work on the soul into Latin. Later readers adopted, revised and challenged its distinctions (Hasse, §§1 and 5).
Averroes and Thomas Aquinas, for example, differed from Avicenna over how estimation applies to human beings (Hasse, §5.1). Influence therefore includes disagreement. It does not mean later philosophers simply copied one complete model.
How we know
What survives: Avicenna’s works, translations, and the combined autobiographical and biographical account.
Whose voices are missing: These philosophical passages do not tell us how ordinary people described their own thinking or experienced care.
What is uncertain: His exact birth year, some details of composition, and how technical terms line up across Arabic, Latin and English.
Then vs. now
The distinctions between receiving, retaining and interpreting information make Avicenna’s questions readable today. Their place inside a theory of soul and intellect is equally important. Similar-sounding terms do not establish that he discovered current brain systems or that modern psychology followed a single path from his books.