ad found an interval in which to execute what was still undone
of the original draft of the Third Book. In working out the logical
theory of those laws of nature which are not laws of Causation, nor
corollaries from such laws, I was led to recognize kinds as realities in
nature, and not mere distinctions for convenience; a light which I had
not obtained when the First Book was written, and which made it
necessary for me to modify and enlarge several chapters of that Book.
The Book on Language and Classification, and the chapter on the
Classification of Fallacies, were drafted in the autumn of the same
year; the remainder of the work, in the summer and autumn of 1840. From
April following to the end of 1841, my spare time was devoted to a
complete rewriting of the book from its commencement. It is in this way
that all my books have been composed. They were always written at least
twice over; a first draft of the entire work was completed to the very
end of the subject, then the whole begun again _de novo_; but
incorporating, in the second writing, all sentences and parts of
sentences of the old draft, which appeared as suitable to my purpose as
anything which I could write in lieu of them. I have found great
advantages in this system of double redaction. It combines, better than
any other mode of composition, the freshness and vigour of the first
conception, with the superior precision and completeness resulting from
prolonged thought. In my own case, moreover, I have found that the
patience necessary for a careful elaboration of the details of
composition and expression, costs much less effort after the entire
subject has been once gone through, and the substance of all that I find
to say has in some manner, however imperfect, been got upon paper. The
only thing which I am careful, in the first draft, to make as perfect as
I am able, is the arrangement. If that is bad, the whole thread on which
the ideas string themselves becomes twisted; thoughts placed in a wrong
connection are not expounded in a manner that suits the right, and a
first draft with this original vice is next to useless as a foundation
for the final treatment.

During the re-writing of the _Logic_, Dr. Whewell's _Philosophy of the
Inductive Sciences_ made its appearance; a circumstance fortunate for
me, as it gave me what I greatly desired, a full treatment of the
subject by an antagonist, and enabled me to present my ideas with
greater clearness and em