has a 'tendency' to preserve the desirable mean. The phrase, then, can only have a distinct meaning when the conflicting forces represent two independent or really separable forces. To use an illustration given by Malthus, we might say that a man had a 'tendency' to grow upwards; but was restrained by a weight on his head. The man has the 'tendency,' because we may regard the weight as a separable accident. When both forces are of the essence, the separate 'tendencies' correspond merely to our way of analysing the fact. But if one can be properly regarded as relatively accidental, the 'tendency' means the way in which the other will manifest itself in actual cases. In 1829, Senior put this point to Malthus.[227] What, he asked, do you understand by a 'tendency' when you admit that the tendency is normally overbalanced by others? Malthus explains his meaning to be that every nation suffers from evils 'specifically arising from the pressure of population against food.' The wages of the labourer in old countries have never been sufficient to enable him to maintain a large family at ease. There is overcrowding, we may say, in England now as there was in England at the Conquest; though food has increased in a greater proportion than population; and the pressure has therefore taken a milder form. This, again, is proved by the fact that, whenever a relaxation of the pressure has occurred, when plagues have diminished population, or improvements in agriculture increased their supply of food, the gap has been at once filled up. The people have not taken advantage of the temporary relaxation of the check to preserve the new equilibrium, but have taken out the improvement by a multiplication of numbers. The statement then appears to be that at any given time the population is in excess. Men would be better off if they were less numerous. But, on the other hand, the tendency to multiply does not represent a constant force, an irresistible instinct which will always bring men down to the same level, but something which, in fact, may vary materially. Malthus admits, in fact, that the 'elasticity' is continually changing; and therefore repudiates the interpretation which seemed to make all improvement hopeless. Why, then, distinguish the 'check' as something apart from the instinct? If, in any case, we accept this explanation, does not the theory become a 'truism,' or at least a commonplace, inoffensive but hardly instructive? Does it amount to more than the obvious statement that prudence and foresight are desirable and are unfortunately scarce? III. MORAL RESTRAINT