Husserl, with respect to natural attitude, makes a crucial distinction between natural sciences and phenomenology, and this distinction provides an appropriate opportunity to enquire into the foundations of science from the phenomenological viewpoint. Here we consider mathematics and physics (as the ideal-type of natural science) from this viewpoint. We see that mathematics as the theory of manifolds, reconstructs the ideal world which is recognized as 'the scientific research field (especially in case of physics). Husserl's viewpoint in mathematics and natural sciences respectively tends to formalism and pragmatism.