And I cannot help again reminding the reader of a distinction which, it appears to me, ought particularly to be attended to in the present question: I mean, the essential difference there is between an unlimited improvement and an improvement the limit of which cannot be ascertained.

The former is an improvement not applicable to man under the present laws of his nature.

The latter, undoubtedly, is applicable.
The real perfectibility of man may be illustrated, as I have mentioned before, by the perfectibility of a plant.

The object of the enterprising florist is, as I conceive, to unite size, symmetry, and beauty of colour.

It would surely be presumptuous in the most successful improver to affirm, that he possessed a carnation in which these qualities existed in the greatest possible state of perfection.
However beautiful his flower may be, other care, other soil, or other suns, might produce one still more beautiful.
Yet, although he may be aware of the absurdity of supposing that he has reached perfection, and though he may know by what means he attained that degree of beauty in the flower which he at present possesses, yet he cannot be sure that by pursuing similar means, rather increased in strength, he will obtain a more beautiful blossom.