Avenarius defines this dependence which I emphasised so often. If he is to give us a general theory, above all parties and including all, then here, as in the presupposition from which he starts, he must keep free from all dogmatic definitions. Hence he says: we know nothing of any mediation between “physical” and “psychical”; we accept no soul or reason, no consciousness, as a kind of spiritus rector—we know nothing of any transition from the physical to the psychical, but we also know nothing of any principle of parallelism between the two series of phenomena, nor of any causal connexion whatever. This all proceeds from special theory. What we know and have to determine is merely this: where “psychical values” are found these definite physiological states are also present, and differences in the physiological functions of organisms are accompanied by differences in the psychical values which are stated by the same individuals.
But to determine this it is quite enough to say: we have a relation between two terms such that if the one term alters, then the second alters also. This relation Avenarius describes, connecting it with the mathematical conception of function as a logical functional-relation.
By this conception of the logical functional-relation Avenarius is enabled to avoid completely the conception of causality, he has no further need of it; and this is the more advantageous because even causality itself conceals something dogmatic, something which is not to be found by pure description.
Here Avenarius agrees also with the well-known physicist and philosopher of Vienna, Ernst Mach. The latter, in his Prinzipien der Wärmelehre, says in an interesting chapter on Causality and Explanation (p. 433): “When we try to get rid of the traces of fetishism still adhering to the concept of cause, when we consider that as a rule no one cause can be assigned, but that a fact is generally determined by a whole system of conditions, then we are led to relinquish altogether the concept of cause. It is far better to regard the conceptually determining elements of a fact as mutually dependent, in exactly the same sense as does the mathematician, or geometrician.” And again on p. 435 he says: “Only the relation of the actual to the actual has any value, and this relation is exhausted by description”.
To Avenarius the important point was the methodological need, that just as we are able to think of the lower organised nervous systems as functioning without consciousness, so also we should be able to think of all human doing and
