In lieu of the various requests which the anxiety of authorship addresses to the unknown reader, I advance but this one; that he will either pass over the following chapter altogether, or read the whole connectedly. The fairest part of the most beautiful body will appear deformed and monstrous, if dissevered from its place in the organic whole. Nay, on delicate subjects, where a seemingly trifling difference of more or less may constitute a difference in kind, even a faithful display of the main and supporting ideas, if yet they are separated from the forms by which they are at once clothed and modified, may perchance present a skeleton indeed; but a skeleton to alarm and deter. Though I might find numerous precedents, I shall not desire the reader to strip his mind of all prejudices, nor to keep all prior systems out of view during his examination of the present. For in truth, such requests appear to me not much unlike the advice given to hypochondriacal patients in Dr. Buchan’s domestic medicine; videlicet, to preserve themselves uniformly tranquil and in good spirits. Till I had discovered the art of destroying the memory a parte post, without injury to its future operations, and without detriment to the judgment, I should suppress the request as premature; and therefore, however much I may wish to be read with an unprejudiced mind, I do not presume to state it as a necessary condition. The extent of my daring is to suggest one criterion, by which it may be rationally conjectured beforehand, whether or no a reader would lose his time, and perhaps his temper, in the perusal of this, or any other treatise constructed on similar principles. But it would be cruelly misinterpreted, as implying the least disrespect either for the moral or intellectual qualities of the individuals thereby precluded. The criterion is this: if a man receives as fundamental facts, and therefore of course indemonstrable and incapable of further analysis, the general notions of matter, spirit, soul, body, action, passiveness, time, space, cause and effect, consciousness, perception, memory and habit; if he feels his mind completely at rest concerning all these, and is satisfied, if only he can analyse all other notions into some one or more of these supposed elements with plausible subordination and apt arrangement: to such a mind I would as courteously as possible convey the hint, that for him the chapter was not written. Vir bonus es, doctus, prudens; ast haud tibi spiro.