Alongside with his philosophical studies, Ibn Sina has dealt with nature in order to gain a firm knowledge of nature and discovering scientific rules which govern it. Ibn Sina's view of nature, as a stage in infinite orders of existence which in a longitudinal order (on the basis of cause and effect) reaches to necessary by-itself, has been a major factor that his study of nature to have a religious tinge. Although as a experimental scholar he has used the method of induction and objective observation, but metaphysical principles in peripatetic philosophy has been a dominant element is his mind, and in different stages experimental method has played its own role. Therefore Ibn Sina's study of nature is not merely a result of method of induction and objective observation, but by completing the method of induction through rational argument he has produced certain propositions and has discovered scientific laws. He repeatedly points to sensual perception and imperfect induction and insists on the necessity of benefiting from intellect for supplementing this understanding and attainment of certainty. The aim of this article is to examine the method of Ibn Sina in knowing nature; for this purposed I have made use of what he has propose in his logical and philosophical (epistemology) discussions about empirical science or experimental method as a means of obtaining definitive knowledge concerning nature.
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