are based upon pure conceptions, and uninfluenced by any empirical
element, or any peculiar intuition leading to determinate
experience, renders this completeness not only practicable, but also
necessary.

Tecum habita, et noris quam sit tibi curta supellex.
-- Persius. Satirae iv. 52.

Such a system of pure speculative reason I hope to be able to
publish under the title of Metaphysic of Nature*. The content of this
work (which will not be half so long) will be very much richer than
that of the present Critique, which has to discover the sources of
this cognition and expose the conditions of its possibility, and at
the same time to clear and level a fit foundation for the scientific
edifice. In the present work, I look for the patient hearing and the
impartiality of a judge; in the other, for the good-will and
assistance of a co-labourer. For, however complete the list of
principles for this system may be in the Critique, the correctness
of the system requires that no deduced conceptions should be absent.
These cannot be presented a priori, but must be gradually
discovered; and, while the synthesis of conceptions has been fully
exhausted in the Critique, it is necessary that, in the proposed work,
the same should be the case with their analysis. But this will be
rather an amusement than a labour.

[*Footnote: In contradistinction to the Metaphysic of Ethics. This
work was never published.]