the role of hypothesis in Cartesian science

At first, it seems that in Cartesian science which seeks to master the world based on its rationalistic and ontological foundations, there is no room for hypothesis of any kind; because whatever appears before the modern reason, is so clear that needs not to any assumption. This view is both correct and incorrect. The Cartesian tree of knowledge has three parts within first two parts of which, i. e. metaphysics as its root and physics as its trunk, only reason is absolute sovereign, while its third part, i. e. the triad branches including medicine, mechanics, and morals cannot be established without hypotheses. The main role of hypothesis is making this tree to be fruitful in its three branches. Experience as the phase of fruit-gathering from this tree is impossible without hypothesis, and this is the very turning-point of which Descartes speaks as his practical philosophy which “makes us the lords and masters of the world”. Hypothesis, as the linkage between reason and experience, is of so irreplaceable role without which Cartesian scientist cannot be successful in bridging the gap between reason, from one hand, and sensation and imagination, from the other.