184. Degrees are of two kinds-degrees of height and degrees of breadth. A knowledge of degrees is, so to speak, the key to laying open the causes of things and entering into them. Without that knowledge, scarcely anything of causation can be known; for without it the objects and subjects of both worlds appear so of a piece as to have nothing in them beyond whatever is visible to the eye. And yet relatively to the elements which lie within, what is visible to the eye is as one compared to several thousands, indeed to tens of thousands. The interior elements which are not apparent can by no means be revealed unless one knows degrees. For outward elements give way to interior ones and through these to inmost ones through degrees-not through continuous degrees, but through discrete degrees.  Continuous degrees is the term we use for diminutions or decreases in a progression from coarser to finer, or from denser to rarer; or rather they are as the increments or increases in a progression from finer to coarser, or from rarer to denser, precisely as is the case in the progression of light to dark or of heat to cold. Discrete degrees, on the other hand, are completely different. They are like prior, subsequent and last elements, or like end, cause and effect. We call these discrete degrees, because the prior element exists in itself, the subsequent element in itself, and the last element in itself, but yet taken together they form a single entity.  The atmospheres from the highest to the lowest or from the sun to the earth, called ethers and airs, are distinguished into degrees of this kind. They are also comparable to simple substances, aggregates of these, and still further aggregates of these again, which taken together are called a composite. These latter degrees are discrete, because they are distinctly constituted, and they are what we mean by degrees of height. Those other degrees, however, are continuous, because they grow by continuous increments, and they are what we mean by degrees of breadth.