Malthus puts it, he is right in calling it a case of arithmetical progression: and his error is in putting that case as a logical counterpart to his other case. 2. Mr. Hazlitt says--'This, Mr. Editor, is the writer whom "our full senate call all-in-all sufficient."'--And why not? I ask. Mr. Hazlitt's inference is--that, because two propositions in Mr. Malthus's Essay are overthrown, and because these two are propositions to which Mr. Malthus ascribes a false importance, in relation to his theory, therefore that theory is overthrown. But, if an architect, under some fancied weakness of a bridge which is really strong and self-supported, chooses to apply needless props, I shall not injure the bridge by showing these to be rotten props and knocking them away. What is the real strength and the real use of Mr. Malthus's theory of population, cannot well be shown, except in treating of Political Economy. But as to the influence of his logical errors upon that theory, I contend that it is none at all. It is one error to affirm a different law of increase for man and for his food: it is a second error to affirm of a perfect state an attribute of imperfection: but in my judgment it is a third error, as great as either of the others, to suppose that these two errors can at all affect the Malthusian doctrine of Population. Let Mr. Malthus say what he will, the first of those errors is not the true foundation of that doctrine; the second of those errors does not contain its true application.