Now two lines of criticism suggest themselves. In the first place, the concluding sentence of the quotation is a _non-sequitur_. If there be a definite, absolute quantity of energy, then its distribution among objects can give absolute quantities of value. Reservoirs connected by pipes may among them contain a definite quantity of water, and increase in the volume of water in one may be at the expense of all the others. But still the amount of water in each is an absolute amount. This criticism, I may note, Professor Seligman concurs in. Conceding that a definite amount of value may exist in each object, he holds that there is, none the less, a relativity about value in the sense that increase in the value of one item can only come from a decrease in the value of another, and _vice versa_. The other line of criticism calls attention to the identification of "energy of valuation" with "nervous energy." That the two are identical would be maintained only by the crudest materialism. The one is a physical force; the other is a psychical force. While nervous energy and energy of valuation may be connected, the nature of the connection is surely not so well known as to justify the assumption that definite limitation in the one implies a precisely corresponding limitation in the other.[194] There is no justification--at least in the present state of psychological knowledge--for holding that the law of the "conservation of energy" applies to psychical energy.[195] Some concrete illustrations will make clearer the difficulties of the doctrine, as applied to economic life. Assume a group of men on board a whaling vessel, who suddenly discover that they will be obliged to spend the winter in the ice-zone, instead of reaching home in the fall as they had planned. Will not the value of everything in their store of provisions be increased? Will not their whole stock of wealth have a greater value? But this, Professor Seligman objects, is because they are in a situation such that opportunity for reproduction is lacking, and he raises the question as to whether the same situation is possible in economic life on a large scale, where wealth is being constantly produced. Well, assume that a crop failure on a large scale occurs. Will not the value of the total existing supply of the articles in which there is a failure be raised? And will not other competing articles of food have their values increased also? But, Professor Seligman would retort, these increases would be at the expense of the values of the half-grown fields of grain, and at the expense of articles other than food. Granted: but what evidence is there of exact equivalence? And further, assume that half of every existing stock of commodities, of every sort, were suddenly wiped out. Would the sum total of values remain the same? Only on the assumption that the social value curve for this totality of commodities is a rectangular hyperbola.[196] That this