We refrain at this point from discussing how far a science which aspires to a spiritual understanding of nature, including material processes, needs a revival - in modern form - of the old conception of levity. In our present context it suffices to realize that we understand man's earlier view of nature, and with it the one still held by van Helmont, only by admitting levity equally with gravity into his world-picture. For the four elements, in particular, this meant that the two upper ones were regarded as representing Levity, the two lower ones Gravity.