h are such _materialiter_, _i. e._ which offend against our
_knowing_, may admit of many answers--involving more and less of
truth. But errors, which are such logically, _i. e._ which offend
against the form (or internal law) of our _thinking_, admit of only
one answer. Except by failing of any answer at all, Mr. Hazlitt and I
could not _but_ coincide: as long as we had the same propositions to
examine (which were not of our own choice, but pointed out to us _ab
extra_), and as long as we understood those propositions in the same
sense, no variety was possible except in the expression and manner of
our answers; and to that extent a variety exists. Any other must have
arisen from our understanding that proposition in a different sense.

[Footnote 29: 'Where the error must lie'--_i. e._ to furnish a
sufficient answer _ad hominem_: otherwise it will be seen that I do
not regard either of the two propositions as essential to Mr.
Malthus's theory: and therefore to overthrow those propositions is not
to answer that theory. But still, if an author will insist on
representing something as essential to his theory which is not so, and
challenges opposition to it,--it is allowable to meet him on his own
ground.]

My answer to Mr. Hazlitt therefore is--that in substance I think his
claim valid; and though it is most true that I was not aware of any
claim prior to my own, I now formally forego any claim on my own part
to the credit of whatsoever kind which shall ever arise from the two
objections to Mr. Malthus's logic in his _Essay on Population_. In
saying this, however, and acknowledging therefore a coincidence with
Mr. Hazlitt in those two arguments, I must be understood to mean a
coincidence only in what really belongs to them; meantime Mr. Hazlitt
has used two expressions in his letter to yourself which seem to
connect with those propositions other opinions from which I dissent:
that I may not therefore be supposed to extend my acquiescence in Mr.
Hazlitt's views to these points, I add two short notes upon them:
which however I have detached from this letter--as forming no proper
part of its business.--Believe me, my dear Sir, your faithful humble
servant. X.Y.Z.

1. Mr. Hazlitt represents Mr. Malthus's error in regard to the
different ratios of progression as a _mathematical_ error; but the
other error he calls _logical_. This may seem to lead to nothing
important: it is however not for any purpose of verbal cavil that I