Ma`rifat Falsafi

Definition of "knowledge" is one of the most important and at the same time the most challenging problems in the history of "epistemology". Farabi -heavily influenced by Plato's epistemological system, especially in the treatises "Theaetetus", "Meno", "Republic", "Euthyphro" and "Phaedo"- considers the possible and desired knowledge as "certain knowledge" in the field of worldview and theoretical and non-evident propositions. His definition of "certain knowledge" or "logical certainty in its most specific sense" includes the four pillars of "firm, true and stable belief". Almost all Muslim philosophers, logicians and epistemologists, including the ancients, the late ones and the contemporaries, have embraced the above definition and made their efforts to confirm and complete it. Leaving out the term "truth", however, Avicenna apparently turned to present a "tripartite definition" of knowledge. Regarding the absence of the term "truth" in Avicenna's definition of "knowledge", two hypotheses can generally be imagined: renunciation and deviation, or his adherence to the celebrated definition. Researchers of philosophy and epistemology have accepted the second hypothesis and have proposed at least two interpretations and justifications in order to prove their claim. In their research and by accepting the second hypothesis, the authors have critically repudiated the arguments for other authors presenting a third and novel interpretation. Having cited four evidences from Avicenna's own works, the authors have vindicated the main claim (i.e. Avicenna's commitment and adherence to the Quadruple definition of Farabi and celebrated philosophers and the fact that Avicenna's omission of the term "truth" in the definition of knowledge is merely a matter of formality).