If we compare together scientific statement or address, popular address, and fine language, it is seen directly that all three express the idea with an equal faithfulness as regards the matter, and consequently that all three help us to acquire knowledge, but that as regards the mode and degree of this knowledge a very marked difference exists between them. The writer who uses the language of the beautiful rather represents the matter of which he treats as _possible_ and _desirable_ than indulges in attempts to convince us of its reality, and still less of its necessity. His thought does in fact only present itself as an arbitrary creation of the imagination, which is never qualified, in itself, to guarantee the reality of what it represents. No doubt the popular writer leads us to believe that the matter _really_ is as he describes it, but does not require anything more firm; for, though he may make the truth of a proposition credible to our feelings, he does not make it absolutely certain. Now, feeling may always teach us what _is_, but not what _must be_. The philosophical writer raises this belief to a conviction, for he proves by undeniable reasons that the matter is _necessarily_ so. Starting from the principle that we have just established, it will not be difficult to assign its proper part and sphere to each of the three forms of diction. Generally it may be laid down as a rule that preference ought to be given to the scientific style whenever the chief consideration is not only the result, but also the proofs. But when the result merely is of the most essential importance the advantage must be given to popular elocution and fine language. But it may be asked in _what cases_ ought popular elocution to rise to a fine, a noble style? This depends on the degree of interest in the reader, or which you wish to excite in his mind.