Malthus argues about human life, as Hume argues about miracles. ‘It will be said, perhaps, that the reason why plants and animals cannot increase indefinitely in size, is, that they would fall by their own weight. I answer, how do we know this but from experience? from experience of the degree of strength with which these bodies are formed. I know that a carnation, long before it reached the size of a cabbage, would not be supported by its stalk; but I only know this from my experience of the weakness, and want of tenacity in the materials of a carnation stalk. There are many substances in nature, of the same size, that would support as large a head as a cabbage. ‘The reasons of the mortality of plants are at present perfectly unknown to us. No man can say why such a plant is annual, another biennial, and another endures for ages. The whole affair in all these cases, in plants, animals, and in the human race, is an affair of experience; and I only conclude that man is mortal, because the invariable experience of all ages has proved the mortality of those materials of which his visible body is made. ‘What can we reason but from what we know.’ This is making use of words without ideas. It is endeavouring to confound two things essentially distinct, because the same lax expression may be applied to them both. It is an attempt to deprive men of their understanding, and leave them nothing but the use of their senses, by a trick of language. Does it follow because all our knowledge may be traced in some way to something which may be called _experience_, that all our conclusions are nothing but an affair of memory? Does Mr. Malthus know of only one sort of experience? Is there not a blind and a rational experience? Is it not one thing merely to know a fact, or a number of facts, and another to know the _reason_ of them? Or if our philosopher is determined to intrench himself behind a word, is there not a knowledge founded on the experience of certain positive results, (which often extends no further than those results) and a knowledge founded on the experience of certain general principles or laws, to which all particular effects are subject? Mr. Malthus seems to insinuate that the knowledge of the general law or principle adds nothing to the knowledge of the fact, because both are equally an affair of experience. He might as well assert that a ligature of iron would not strengthen a deal plank, because they are both held together by the same law of cohesion. The fact expresses nothing more than the actual co-existence of certain things in certain circumstances, and while all those circumstances continue, no doubt the same consequences will follow. But we know that they are hardly ever the same, and the question is, which of them is necessary to produce the effect talked of. This the _reason_ points out, that is, it points out a relation between certain things, which has been found to hold not merely in the given circumstances, but