It is, indeed, scarcely possible to advance, even a step in intellectual physics, without the necessity of performing some sort of analysis, by which we reduce to simpler elements, some complex feeling that seems to us virtually to involve them. In the mind of man, all is in a state of constant and ever-varying complexity, and a single sentiment may be the slow result of innumerable feelings. There is not a single pleasure, or pain, or thought, or emotion, that may not,--by the influence of that associating principle, which is afterwards to come under our consideration,--be so connected with _other_ pleasures, or pains, or thoughts, or emotions, as to form with them, forever after, an union the most intimate. The complex, or seemingly complex, phenomena of thought, which result from the constant operation of this principle of the mind, it is the labour of the _intellectual inquirer_ to _analyze_, as it is the labour of the _chemist_ to reduce the compound bodies, on which he operates, however close and intimate their combination may be, to their constituent elements. The process, and the instruments by which the analyses are carried on, are, indeed, as different as matter is from mind,--cumbrous as matter, in the one case,--in the other, simple and spiritual as mind itself. The aggregates of matter we analyze by the use of other matter, adding substance after substance, and varying manipulation after manipulation;--the complex mental phenomena we analyze virtually by mere reflection; the same individual mind being the subject of analysis, the instrument of analysis, and the analysing inquirer.