For my part I hold firmly to the economic notion of the hedonistic guide, to utility-ophelimity, to final utility, and even to the explanation (economic) of interest on capital as arising from the different degrees of utility possessed by present and future goods. But this does not satisfy the desire for a _sociological_, so to speak, elucidation of interest on capital; and this elucidation, with others of the same kind, can only be obtained from the comparative considerations put before us by Marx.[38] III CONCERNING THE LIMITATION OF THE MATERIALISTIC THEORY OF HISTORY _Historical materialism a canon of historical interpretation: Canon does not imply anticipation of results: Question as to how Marx and Engels understood it: Difficulty of ascertaining correctly and method of doing so: How Marxians understand it: Their metaphysical tendency: Instances of confusion of concepts in their writings: Historical materialism has not a special philosophy immanent within it._ Historical materialism if it is to express something critically acceptable, can, as I have had occasion to state elsewhere,[39] be neither a new _a priori_ notion of the philosophy of history, nor a new method of historical thought; it must be simply a _canon_ of historical interpretation. This canon recommends that attention be directed to the so-called economic basis of society, in order that the forms and mutations of the latter may be better understood. The concept canon ought not to raise difficulty, especially when it is remembered that _it implies no anticipation of results_, but only an aid in seeking for them; and is entirely of empirical origin. When the critic of the text of Dante's _Comedia_ uses Witte's well-known canon, which runs: '_the difficult reading is to be preferred to the easy one_,' he is quite aware that he possesses a mere instrument, which may be useful to him in many cases, useless in others, and whose correct and advantageous employment depends entirely on his caution. In like manner and with like meaning it must be said that historical materialism is a mere _canon_; although it be in truth a canon _most rich in suggestion_. But was it in this way that Marx and Engels understood it? and is it in this way that Marx's followers usually understand it?