Spinoza's commitment to intelligibility is extremely ambitious in at least two respects. First, he insists that each thing is intelligible, there are no facts impervious to explanation. Second, he holds that these explanations are—in principle—graspable by us. Our minds are, of course, limited in some ways; there are limits to how many things we can fully grasp.

Spinoza (2008) - One: Spinoza's Understanding and Understanding Spinoza