Abstract
Avicenna, beside his theoretical discussions about experimentation, practically applied his experimental method to natural sciences studies such as medicine, biology, and meteorology. His theoretical discussions subsume propositions concerning the conditions under which experimental knowledge is attained, the components of this knowledge and its functions. Some of these propositions are as follows: necessity of recurrent observations for acquiring experimental knowledge, certainty plus conditional universality of such knowledge, and its role as demonstrative premises. Investigating the application of his theory in natural sciences propound two new features which were not elaborated in the theoretical discussions: fallibility of experimental knowledge and necessity of systematic observation. This research, using the analytic method and referring to both philosophical and scientific works of Avicenna, clarifies that a comprehensive definition of experimentation is dependent on considering extracted points from practical application of experimental knowledge, beside its theoretical components