such; the error results from a conclusion from the following major premise: “If dark grey passes regularly through all shades to white; the cause is _always_ the light, which strikes differently upon projections and depressions, _ergo_—.” (2.) “If there is no money in my safe, the cause is _always_ that my servant has got a key for it: _ergo_—.” (3.) “If a ray of sunlight, broken through a prism, _i.e._, bent up or down, appears as a coloured band instead of round and white as before, the cause must always be that light consists of homogeneous rays, differently coloured and refrangible to different degrees, which, when forced asunder on account of the difference of their refrangibility, give an elongated and variously-coloured spectrum: _ergo—bibamus!_”—It must be possible to trace every error to such a conclusion, drawn from a major premise which is often only falsely generalised, hypothetical, and founded on the assumption that some particular cause is that of a certain effect. Only certain mistakes in counting are to be excepted, and they are not really errors, but merely mistakes. The operation prescribed by the concepts of the numbers has not been carried out in pure intuition or perception, in counting, but some other operation instead of it. As regards the _content_ of the sciences generally, it is, in fact, always the relation of the phenomena of the world to each other, according to the principle of sufficient reason, under the guidance of the _why_, which has validity and meaning only through this principle. _Explanation_ is the establishment of this relation. Therefore explanation can never go further than to show two ideas standing to each other in the relation peculiar to that form of the principle of sufficient reason which reigns in the class to which they belong. If this is done we cannot further be asked the question, _why_: for the relation proved is that one which absolutely cannot be imagined as other than it is, _i.e._, it is the form of all knowledge. Therefore we do not ask why 2 + 2 = 4; or why the equality of the angles of a triangle determines the equality of the sides; or why its effect follows any given cause; or why the truth of the conclusion is evident from the truth of the premises. Every explanation which does not ultimately lead to a relation of which no “why” can further be demanded, stops at an accepted _qualitas occulta_; but this is the character of every original force of nature. Every explanation in natural science must ultimately end with such a _qualitas occulta_, and thus with complete obscurity. It must leave the inner nature of a stone just as much unexplained as that of a human being; it can give as little account of the weight, the cohesion, the chemical qualities, &c., of the former, as of the knowing and acting of the latter. Thus, for example, weight is a _qualitas occulta_, for it can be thought away, and does not proceed as a