Skepticism is thus a resting-place for human reason, where it can reflect upon its dogmatic wanderings and make survey of the region in which it find… - Immanuel Kant

Es ist Gut.

The character of the species, as it is indicated by the experience of all ages and all peoples, is this: that taken collectively (the human race as one whole), it is a multitude of persons, existing successively and side by side, who cannot do without associating peacefully and yet cannot avoid constantly offending one another.

Newton... (after having remarked that geometry only requires two of the mechanical actions which it postulates, namely, to describe a straight line and a circle) says: geometry is proud of being able to achieve so much while taking so little from extraneous sources. One might say of metaphysics, on the other hand: it stands astonished, that with so much offered it by pure mathematics it can effect so little. In the meantime, this little is something which mathematics indispensably requires in its application to natural science, which, inasmuch as it must here necessarily borrow from metaphysics, need not be ashamed to allow itself to be seen in company with the latter.