Ibn Sina: How to Tell a Blueprint from a Barn and Not Confuse Thought with Brain

"His essence exists."

Ibn Sina, The Book of Healing, "On the Soul," I.1, 15.17–16.17, thought experiment; English translation by Peter Adamson, Fedor Benevich, p. 148. English back-rendering of the author's Russian text based on Adamson and Benevich; not to be passed off as the verbatim wording of the English scholarly source. This is merely what the hypothetical participant affirms about himself within the thought experiment, not a laboratory report.

What This Article Is About

The human mind loves confusing a grand architectural plan with an actual building. We swoon over blueprints of palaces, utterly oblivious to the fact that right now there is only a muddy puddle on the ground and an empty pocket. A thousand years ago, Ibn Sina (known to the West as Avicenna) was already systematically sorting out: what a thing is in its essence, and whether it exists in reality at all. In this article, stripped of academic unction, we dissect the distinction between essence and existence, between the possible and the necessary, and then examine his famous "Flying Man" thought experiment. Along the way, we will clarify why this experiment is a rigorous philosophical probe into self-awareness rather than a sensory-deprivation tank or an fMRI machine. Our mundane example of a house blueprint is a strictly limited analogy intended for ordinary intuition, not an ironclad proof of metaphysics. We also compare Avicenna with Descartes, Thomas Aquinas, and the Buddhist canon to demonstrate that sharing sonorous philosophical terms does not mean arriving at the same conclusions.

I. What It Is — And Whether It Is

Essence is the answer to the question "what kind of thing is this?", while existence answers "is it actually there in reality?". In Ibn Sina, this is a metaphysical distinction—analyzed in detail by Amos Bertolacci—that strictly separates mental existence (in the mind) from external existence (outside thought, not merely physical).

Suppose a blueprint for a lavish mansion lies right before you. You can argue for hours about ceiling heights and tile patterns, but you will not shelter from the rain under that piece of paper: the doorknob on the drawn door simply does not exist. The blueprint exists on paper, the concept exists in your head, while the house itself does not exist in the physical world at all. Our house analogy is intuitive and visual, but it remains a strictly limited example, not a rigorous proof of Avicenna's entire metaphysical system.

In daily life, the average mind commits this error constantly: a startup founder drafts a slide deck and proudly declares, "We have built a platform!". No, you have built a PDF file; an actual platform requires servers, developers, and capital. Similarly, a romantic declares, "I am the kind of person who always supports loved ones." That is merely an attractive self-description inside your head; whether such support exists in reality is demonstrated only when you actually have to haul someone else's heavy couch up five flights of stairs.

II. The Possible Is Not a Trivial Fluke

When Avicenna speaks of the "possible," he does not mean a minor accident or casual mishap. The "possible in itself" is that whose essence does not guarantee its own necessary arrival into being. If it has come into being, an external cause was at work, rendering it "necessary through another." All of this is fundamentally distinct from the "necessary in itself."

The ordinary mind's primary trap is confusing subjective psychological certainty with modal necessity. You perceive a tree outside the window with absolute certainty, but the fact of your reliable observation does not make the tree modally necessary in itself: had a fierce storm struck five years ago, that sapling would never have survived. When, after a botched meeting, a self-styled intellectual shrugs, "Well, it couldn't have gone any other way!", they are simply indulging in hindsight rationalization. A message was delayed, an address was mixed up—yes, under those conditions the meeting fell through. But causality is neither an indulgence for laziness nor an instruction for inaction, nor does causality settle the entire philosophical problem of free will! Your own actions are an integral part of the causal chain, so shifting personal passivity onto the fatalistic "determination of all things" will not hold up.

III. The Necessary Ground Is Not a Gigantic Physical Object

In inquiring into the First Cause, Avicenna is not trying to squeeze yet another colossal super-object—like a hovering cosmic monolith—into the universe. He asks: why is there a world of dependent, contingent things at all, and where does the chain of dependence terminate? As Dimitri Gutas demonstrates in his overview of Ibn Sina's philosophy, this is a rigorous logical system, not poetic ecstasy.

Take note, however: designating something as a "ground that requires no ground" is merely a verbal definition. The definition of a ground in no way proves the actual existence of that ground in external reality! Legitimate philosophical objections remain entirely valid: why must a chain of causes terminate anywhere at all, and are we shifting the meaning of the word "cause" midway through the argument? When modern life coaches proclaim that "the foundation of business is trust," they are merely juggling metaphors. Human trust fluctuates with market conditions, and equating it to necessary being is a cheap rhetorical trick.

IV. The Soul Is Not Equivalent to a List of Pleasant Qualities

For a contemporary person, "soul" suggests warmth, emotional depth, or a burst of compassion. For Ibn Sina, it is strictly a technical term of historical rational psychology and epistemology. It is a systematic inquiry into the soul and its faculties of perception and intellect within a historical framework—not a functional list, not a synonym for moral goodness, and not a modern neurobiological model.

As Alfred Ivry explains, the soul's faculties were examined as an ordered hierarchy. When a guitarist beats their chest insisting, "I poured my soul into that solo," a physiologist calmly records muscular contractions and neural impulses. Describing bodily conditions does not invalidate the subjective experience of music, but an ecstatic experience does not prove the existence of an independent immaterial substance. The descriptions simply serve different analytical purposes.

V. The Man Who Senses No Body

We arrive at the centerpiece: the "Flying Man." Imagine a human being mentally created all at once, without any prior personal history or memories. He hovers suspended in air, his eyes shut, his ears hearing nothing, his limbs outstretched so that no part of his body touches another.

Halt! Peter Adamson and Fedor Benevich specifically emphasize that this is a conceivability thought experiment, not a clinical sensory-deprivation log or an empirical laboratory report of brain shutdown. Avicenna posits that the suspended subject would still affirm self-awareness: "I am!"—even while knowing nothing of his own hands, heart, or liver; this assumed self-awareness is Avicenna's postulate within the thought experiment, not an empirically verified fact.

Does this establish that the soul can exist without a body? Adamson and Benevich closely examine the controversial conditions governing epistemic access to essence. We can formulate a bridging condition: "whatever is essential to my being must necessarily appear within my immediate self-awareness." Let this be stated clearly three times over: this bridging formula is merely our heuristic check of the logical transition; it is NOT a quotation from Avicenna, NOT a definitive historical reconstruction, and NOT an established fact. The absence of bodily awareness does not prove that the body is unnecessary for consciousness to exist (just as an audience member in the dark perceives the stage while being oblivious to the spotlights without which the performance is impossible). At the same time, bodily conditions do not constitute the whole answer or exhaust immediate self-awareness.

VI. Knowing Oneself Is Not Knowing Everything About Oneself

The fact that you are aware of your own presence right now ("I exist") does not mean that you exhaustively comprehend who you are or why you make foolish choices. Immediate access to experience is fundamentally not identical to knowing the underlying causes of that state.

In the scholarly conversation between Peter Adamson and Jari Kaukua, the subtle complexity of this self-awareness is parsed. In ordinary life, people conflate distinct categories into an indiscriminate tangle:

Experience: "I feel hurt and aggrieved" (an immediate subjective fact).
Description: "I am upset."
Causal Hypothesis: "He orchestrated this deliberately to humiliate me!".
Norm: "Therefore, I must retaliate."

Experience, description, causal hypothesis, and norm are fundamentally distinct! A causal hypothesis requires verification; you cannot reliably deduce the internal motives of another person from your own hurt feelings. Passing off your personal resentment as infallible mind-reading of others' motives is a classic maneuver of an injured ego.

VII. Imagination Is No Substitute for Empirical Observation

A thought experiment tests the conceptual consistency of ideas, but it cannot substitute for actual empirical observation. As Jon McGinnis points out, Ibn Sina's physics and natural philosophy rested upon the broader scientific framework of his era, not upon an isolated thought image.

If an IT department invents an idealized customer who studiously reads five pages of documentation before clicking a button, the system design will look flawless on paper. But that mental model does not reveal what actual users will notice or how they will behave. A thought model is useful for catching internal logical inconsistencies, but asserting that it has proven how real people behave in reality is professional self-sabotage.

VIII. Understanding Requires a Bridging Step

Memorizing clever terms like "essence" and "existence" is trivial; grasping the logical step connecting them is entirely different. In Avicenna's logical treatises, examined by Riccardo Strobino, demonstration depends on rigorous middle terms and inferential links, not on appeals to authority.

Someone catches a catchphrase: "Relationships are built on trust!"—and promptly deduces: "Therefore, reviewing a partner's financial reports is an insult." A vital bridging step has been skipped: why does transparency destroy trust rather than protect it? To avoid embarrassment, apply this test: identify one reliable fact, one bridging step of reasoning, and one essential unknown. For instance: a colleague did not open the email (fact); therefore, they missed the conference call (hypothetical bridging step); but whether they had other reasons or are even alive and well remains unknown.

IX. One Self-Awareness and Several Philosophical Agendas

When philosophers invoke the "I," they are often addressing completely different problems without any mutual coordination:

Ibn Sina vs. Descartes: In Avicenna's On the Soul, bodily sensations are mentally stripped away from the flying man. In Descartes' Part IV of the Discourse on Method, the foundation is radical methodical doubt directed at all sensory input, dreams, and mathematical truths. The conditions of doubt and the conditions of sensory isolation are completely different, and no direct historical influence of Avicenna on Descartes is established here.
Ibn Sina vs. Buddhism: In the Buddhist discourse SN 22.59, the five aggregates (form, feeling, perception, fabrications, consciousness) are systematically analyzed to show that none of them can be identified as a permanent self. This is neither ego psychology nor the same experiential realization, nor is it an empirical confirmation of Avicenna's metaphysics of the soul; its liberating purpose concerns non-appropriation of the aggregates as a self, not the demonstration of a substantial soul.
Ibn Sina vs. Thomas Aquinas: Aquinas's Third Way proceeds from physical corruption and generation—things naturally come into being and perish in time. Avicenna's modal framework is different: a thing is considered according to its essence as possible in itself.
Ibn Sina vs. Spinoza: In Spinoza, substance and modes are distinct, and necessity has its own philosophical account; his total necessity is not identical to Avicenna's nuanced modal system of possibility and caused necessity.

X. Between a Clear Concept and an Open Question

Ibn Sina does not peddle cheap panaceas of omniscience. His thought is anchored in the strict discipline of limits: essence in the intellect does not guarantee external existence in the world; the empirical observability of a fact does not make it an ultimate necessity; and the immediate intuition "I exist" does not unravel the biological mechanisms of the brain.

Wisdom does not lie in memorizing dogma and patronizingly patting your interlocutor on the back. It begins with the humility to state: "Here is a formal definition; here is a mental image; this premise I understand, but that inferential leap is not yet proven to me." Distinguishing the blueprint from the actual barn might help frame the next question with far greater precision.

Practical Exercise

This exercise is strictly voluntary, offers no medical diagnoses, makes no promises of nirvana, and requires no commitment to medieval metaphysics. Select any current commitment, project, or interpersonal friction, and break it down across these dimensions:

Description vs. Actual Presence: Write down the precise phrasing of your project or promise. Separately list what already exists in reality and what is still merely conceived. The description is not the execution.
Condition vs. Habit: Isolate what is indispensable for the task to work (the necessary condition), and separate it from mere ritual habits. You can outline a project in an expensive leather notebook or on a greasy napkin; the leather notebook is merely a habit.
One Transition + The Unknown: If anxiety strikes, isolate the raw fact: "I feel a tightness in my throat." Make exactly one bridging step: "This may be connected to the upcoming meeting." And immediately articulate the unknown: "The cause of this sensation remains hypothetical; what the other person will say and how the meeting will unfold is entirely unknown to me."

Key Quotation

"I think, therefore I am."

René Descartes, Discourse on the Method, IV; English translation by John Veitch. English back-rendering of the author's Russian text based on Veitch; not to be passed off as the verbatim wording of the English scholarly source. Cited to compare the nature of self-certification while preserving the fundamental divergence in the exploratory objectives of the two thinkers.

Cross-Traditional Connections

These are analytical comparisons drawn by the authors of this article: historical influence is not asserted where direct textual evidence is lacking.

Subject	Positions and Sources	Basis of Comparison	Where the Boundary Lies
Essence and Actual Presence	Ibn Sina: Metaphysics — Spinoza, Ethics I, Definitions and Prop. 29	Examining the structure of a thing in relation to the ground of its being.	The modalities are not identical: Spinoza's modes and geometric necessity are distinct from Avicenna's contingent, possible being.
Possible and Necessary	Avicenna: Possible in Itself — Thomas Aquinas, Summa Theologiae I q.2 a.3	Investigating whether finite, contingent entities suffice to account for the world.	Aquinas's Third Way departs from temporal generation and corruption, rather than Avicenna's pure modal analysis of essences.
Self-Certification	Flying Man, On the Soul I.1 — Descartes, Discourse on the Method IV	Affirming the immediate presence of the thinking "I" without sensory reliance.	Descartes employs radical universal doubt, whereas Avicenna employs sensory suspension; no direct historical influence is established here.
Self-Knowledge vs. Appropriation	Flying Man — Buddhist Canon: SN 22.59	The experience of self requires separate investigation.	Avicenna seeks the substantial soul; the sutta instructs non-appropriation of the aggregates as an enduring self. Their aims and conclusions are not identical.
Certainty and Demonstration	Avicenna: Reconstruction of the Argument — Al-Ghazali, §§6–24	Distinguishing the psychological feeling of certainty from the demonstrative power of logic.	Al-Ghazali's skeptical crisis and resolution via divine light is a religious testimony, not an extension of Avicenna's thought experiment.

Primary Sources and References

Primary texts, canonical writings, and scholarly commentaries are distinguished in their respective descriptions. A section heading does not transform a reference commentary into a primary text.

Amos Bertolacci. Ibn Sina’s Metaphysics. Stanford Encyclopedia of Philosophy. Essence/existence, possible/necessary.
Dimitri Gutas. Ibn Sina. Stanford Encyclopedia of Philosophy. Systematic context of philosophy and epistemology.
Alfred Ivry. Arabic and Islamic Psychology and Philosophy of Mind. Stanford Encyclopedia of Philosophy. Historical philosophical psychology.
Peter Adamson, Fedor Benevich. The Thought Experimental Method: Avicenna’s Flying Man Argument. Journal of the American Philosophical Association, 2018. Translation of the passage in "On the Soul," premises, and objections.
Peter Adamson, Jari Kaukua. Journal of the History of Philosophy podcast transcript. Johns Hopkins University Press. Conversation on self-awareness and experience in Avicenna.
Jon McGinnis. Ibn Sina’s Natural Philosophy. Stanford Encyclopedia of Philosophy. Context of natural philosophy and physics.
Riccardo Strobino. Ibn Sina’s Logic. Stanford Encyclopedia of Philosophy. Concepts, definitions, and demonstrative proof.
René Descartes. Discourse on the Method, IV; English translation by John Veitch. Primary text: doubt and self-certification of the thinking subject. Text and referenced section.
Thomas Aquinas. Summa Theologiae, I, q.2, a.3, the Third Way. Primary text: possible and necessary; New Advent English edition. Text and referenced section.
SN 22.59, Pañcavaggi / Anattalakkhaṇa Sutta; translated by Thanissaro Bhikkhu. Primary Buddhist text: impermanence of the five aggregates and their non-appropriation as self. Text and referenced section.
Spinoza. Ethics, I, Definitions III–V and Propositions 15, 18, 29; English translation by R. H. M. Elwes. Primary text: substance, modes, immanent cause, and necessity. Text and referenced section.
Al-Ghazali. Al-Munqidh min al-Ḍalāl / Deliverance from Error; English translation by Richard J. McCarthy. Primary text: certainty, logic, knowledge of the path, and realization; selected §§6–24, 37–45, 80–85. Text and referenced section.

About the Authors

Andrey Zarinsh — author and founder of the United Wisdom project. He explores themes of inner transformation, the unity of traditions, intercultural dialogue, and contemporary spiritual discipline. Instagram: @andrey.zarinsh.

Maria Evilkut — co-author at United Wisdom. Alongside her research work, she strives to test these ideas in practice and observe how principles of unity and mutual understanding operate in real life between people and cultures. Instagram: @ilkutki.