For classical philosophers, the Euclidean axiomatic model represented the ideal framework for constructing deductive scientific systems. Avicenna adopted this model in developing a structured propositional system for metaphysics. Yet several scholars have denied the possibility of such a system, arguing that applying an axiomatic structure to metaphysics is fundamentally misguided. This article addresses the central question of how, and under what conditions of possibility, Avicenna was able to construct a deductive propositional system for metaphysics. The issue is significant because it concerns the very grounds upon which the first systematic and deductive formulation of metaphysics could emerge. Using a descriptive–analytical approach, the study first examines the architecture of Avicenna’s metaphysical system—its components and its internal order—and then explores the conditions that enable its realization. According to Avicenna’s scientology, a metaphysics grounded in the lemma (a priori) method should rely solely on common principles, while a metaphysics proceeding through posterior reasoning (Inni) may draw upon additional axioms. Although Avicenna considers the lemma-based approach possible in itself, its practical difficulty and pedagogical considerations lead him to integrate the posterior method as well. Consequently, metaphysics assumes an “axiom–postulate” hybrid structure. The findings show that Avicenna’s metaphysical system becomes possible only through this combined methodological framework, supported by his ontology of emanation and his epistemology of intellection.
Keywords: Avicenna, Metaphysics, Axiomatic Structure, Propositional System, Burhan-e-Limmi, Burhan-e-Inni, Ontology.
Introduction
In the classical tradition, the deductive rigor found in Euclidean geometry and Archimedean statics was considered the gold standard for scientific knowledge. Aristotle laid the logical foundations for this axiomatic method in his Posterior Analytics, but it was Avicenna who, through his innovative synthesis, founded the first comprehensive propositional system for metaphysics. Avicenna sought to transform metaphysics from a collection of scattered insights into a “Demonstrative Science” (Al-Ilm al-Burhani) that follows a strict hierarchical order.However, the validity of such a system has been challenged by modern thinkers. Paul Foulquié argued that a purely a priori metaphysics is impossible because it relies on the unproven assumption of the identity between thought and being. Similarly, Nicolai Hartmann claimed that ancient ontology failed because it attempted to deduce the “scaffold of existence” from a few abstract concepts, leading to a circular logic. This article investigates the tension between Avicenna’s systematic ambition and these critiques. It aims to clarify the internal logic that allowed Avicenna to believe that metaphysics—the science of the “First Principles”—could be structured as a deductive system comparable to geometry.
Materials & Methods
The methodology of this research is descriptive-analytical, focusing on the internal logic of Avicenna’s seminal works, primarily the Kitab al-Shifa (The Book of Healing), specifically the sections on Burhan (Demonstration) and Ilahiyyat (Metaphysics).
The analytical framework is based on two primary pillars:
-Structural Components: Analyzing the “Mabadi” (Principles) and “Masa’il” (Issues/Problems) that constitute a demonstrative science.
-Structural Order: Investigating the “Arrangement” of propositions, distinguishing between the a priori path (from cause to effect) and the a posteriori path (from effect to cause).
The study also employs a comparative approach by juxtaposing Avicenna’s methodology with the critiques of Paul Foulquié and Nicolai Hartmann to identify the specific ontological and epistemological “conditions of possibility” that sustain the Sinavin system.
Discussion & Result:
1. The Components: Principles and Issues
In Avicenna’s “Scientology,” every demonstrative science consists of Mabadi (starting points) and Masa’il (propositions to be proven). The Mabadi are further divided into:

Axioms (Common Notions): Self-evident truths requiring no proof in any science.
Postulates: Propositions that are not self-evident but are proven in a higher or lower science.

A significant problem arises: Metaphysics is the “Highest Science” (Al-Ilm al-A’la). If it is the highest, it cannot borrow postulates from a “higher” science. This implies that a pure metaphysics should rely solely on axioms. However, Avicenna’s Ilahiyyat clearly utilizes findings from physics (such as the existence of motion or the first mover) and mathematics.
2. The Hybrid Solution: Limmi vs. Inni: The article finds that Avicenna distinguishes between two modes of the science:

The Limmi Path (A Priori): This is metaphysics “in itself.” It moves from the cause (The First Principle) to the effects (creation). While logically possible, Avicenna admits this is extremely difficult for the human intellect.
The Inni Path (A Posteriori/Instructional): For “educational purposes” and due to human intellectual limitations, we must begin with what is “better known to us” (sensible effects) to reach what is “better known by nature” (the First Cause).

Thus, Avicenna’s actual system is an “Axiomatic-Postulate” hybrid. He uses results from natural sciences (Inni) as postulates to build the metaphysical structure, while maintaining that in essence, the science remains deductive.
3. Addressing the Critics:The results indicate that Avicenna provides a robust response to modern skepticism.

Against Foulquié: While Foulquié rejects the union of thought and being as an “idealist” trap, Avicenna’s realism is based on “Essential Union.” The Active Intellect (Aql al-Fa’al) provides the same “Forms” to both the external world and the human mind. Therefore, the deductive order of the mind is not an imposition but a reflection of reality.
Against Hartmann: Hartmann’s critique of “apriorism” is answered by Avicenna’s distinction between the “Order of Existence” and the “Order of Instruction.” Avicenna acknowledges that we start from “secondary data” (the Inni method), but he insists that the goal of the scientist is to eventually reorganize that knowledge into a Limmi (causal) structure.

4. The Ontological Condition: The Theory of Emanation:The ultimate condition of possibility for this system is the Theory of Emanation (Sudur). Because existence itself flows in a strictly ordered, hierarchical descent from the One to the many, a propositional system that mirrors this descent is not only possible but necessary. The “Order” of the system is the “Order” of Being.
Conclusion:
Avicenna successfully constructed a deductive propositional system for metaphysics by navigating the tension between pure logic and human pedagogical needs. The research concludes that the Sinavin system is not a “pure” axiomatic system in the modern mathematical sense, but a sophisticated hybrid. It functions through the integration of Limmi and Inni methods.This construction is made possible by two specific philosophical doctrines:
- Ontologically: The hierarchical nature of reality (Emanation) provides the blueprint for the propositional hierarchy.
- Epistemologically: The mind’s ability to “re-trace” the path of existence—moving from effects back to causes and then re-deducing the effects from those causes—allows for a system that is both grounded in reality and strictly deductive. Avicenna’s metaphysics is, therefore, a “parallelism” between the structure of the mind and the structure of the cosmos.