True science consists in systematically examining all possible cases. Exact political economy has not achieved this until now. It does not even encompass all actual cases. This is one of the reason why exact theory finds itself in opposition to the historical school and why it does not have an awful lot to say to those economists who occupy themselves with issues of practical interest, theories of crisis, cartels and trusts.

The motivationless theory of goods [transfers] can bridge the gulf between history and exact research by securing the important continuity of the research, being linked to both.

The attempt to construct a fundamental taxonomy of the sciences encounters great difficulties. For instance, logicians and mathematicians disagree among themselves about the objects of their respective research; there is no agreement on the relation of theoretical physics to empirical knowledge and to mathematics. The so-called social sciences are particularly difficult to classify. They have not been demarcated by systematic considerations. In Duhem and Poincarè, general considerations are not only exemplified, but the origins of the concepts and of the problems are traced right from the initial observation of facts if at all possible.

I do not think the line of division runs between people with secular and those with transcendental creeds, but rather between people with a centralized and dominating zeal which may possibly lead to self-sacrifice and the sacrifice of others, without tolerance in principle, and people who are tolerant on principle, having perhaps some transcendental creed, or because they, as empiricists, see the multiplicity of all arguing.

The universal jargon, in the sense explained above, is the same for the child and for the adult. It is the same for a Robinson Crusoe as for a human society. If Robinson wants to join what is in a protocol of yesterday with what is in his protocol today, that is, if he wants to make use of language at all, he must make use of the ‘intersubjective’ language. The Robinson of yesterday and the Robinson of today stand precisely in the same relation in which Robinson stands to Friday.

The fiction of an ideal language composed of pure atomic statements is as metaphysical as the fiction of Laplace's 'spirit'. Scientific language, with its ever growing equipment of systematic symbol formations, can by no means be regarded as an approximation to such an ideal language.

In the interest of scientific work, more and more formulations in the unified language of unified science are becoming increasingly precise. No term of unified science, however, is free from imprecision, since all terms are based on terms that are essential for protocol statements, whose imprecision must be immediately obvious to everyone.

Only one language comes into question from the start, and that is the physicalist. One can learn the physicalist language from earliest childhood. If someone makes predictions and wants to check them himself, he must count on changes in the system of his senses, he must use clocks and rulers, in short, the person supposedly in isolation already makes use of the ‘intersensual’ and ‘intersubjective’ language. The forecaster of yesterday and the controller of today are, so to speak, two persons.

Carnap, who has so far probably advanced the work of the Vienna Circle the most towards empiricism, made an attempt to create a constitutive constructive system; in this he distinguished two languages: a ‘monologizing’ (phenomenalist) one and an ‘intersubjective’ (physicalist) one. He tries to deduce the physical one from the phenomenalist.

At first the Vienna Circle analysed ‘physics’ in a narrower sense almost exclusively; now psychology, biology,sociology. The task of this movement is unified science and nothing less.