Logical Investigations to simply say—as is common with Rickert, and with contemporary logic generally—that what Husserl provides in his Logical Investigations is an emendation of Bolzano.68
* * *
Bolzano himself was determined in an essential way by Leibniz; Husserl was as well, and directly—not only via a detour through Bolzano. The connections with Leibniz that Husserl expressed himself on (Logical Investigations vol. 1, §60), concern less the doctrine of truths-in-themselves than another essential element of contemporary philosophy.
With the above, we have shown the roots of the distinction between real and ideal being in thinking, as well as the doctrine of the true proposition as validity. We also looked at the consequences the doctrine of validity has for the development of value philosophy. Moreover, we have already anticipated certain questions of the critique, which according to the arrangement of this course, were reserved for §10. But it only seems that way, for in fact we are not yet prepared to make a critique of—and hence, to take a fundamental stance on—the critique of psychologism. The reason for this is that we have not yet clarified Husserl’s critique of psychologism in [88] its positive core. Rather, we have intentionally sketched out psychologism and Husserl’s critique of it only in the form and to the degree that Husserl laid it out in the first volume of the Logical Investigations and that his contemporaries understood it then and still understand it today. That is, we sketched it out in the form that this critique has taken positively, e.g., in the logic of validity and value.
But we have by no means gone to the core, to the sense in which Husserl wanted these critical affirmations to be understood. Husserl’s critique of psychologism is a critique of psychology—and it intrinsically must be that, if it is to become something positive and not merely an identification and demonstration of errors. It is a critique of psychology in the sense that in place of the function and role that psychology ascribes to itself, a new kind of research is introduced: phenomenology. The fact that the critique of psychologism is really a critique of psychology also shows that, yes, the problems that psychologism claims to answer are conceded and affirmed to be legitimate—but with the proviso that psychology, in both its former and present conditions, is shown to be incapable of solving these questions, or even of asking them in a meaningful way.
This meaning of the critique of psychology is no more understood
68. [Here (Moser, p. 181) Heidegger ends his lecture of Monday, 23 November 1925, to be followed by that of Tuesday, 24 November, which opened with a 1000word summary that is omitted in GA 21.]