Granted that this also is only interpretation--and you will be eager enough to make this objection ?--well, so much the better.
23.

All psychology hitherto has run aground on moral prejudices and timidities, it has not dared to launch out into the depths.

In so far as it is allowable to recognize in that which has hitherto been written, evidence of that which has hitherto been kept silent, it seems as if nobody had yet harboured the notion of psychology as the Morphology and DEVELOPMENT-DOCTRINE OF THE WILL TO POWER, as I conceive of it.
The power of moral prejudices has penetrated deeply into the most intellectual world, the world apparently most indifferent and unprejudiced, and has obviously operated in an injurious, obstructive, blinding, and distorting manner.

A proper physio-psychology has to contend with unconscious antagonism in the heart of the investigator, it has "the heart" against it even a doctrine of the reciprocal conditionalness of the "good" and the "bad" impulses, causes (as refined immorality) distress and aversion in a still strong and manly conscience--still more so, a doctrine of the derivation of all good impulses from bad ones.

If, however, a person should regard even the emotions of hatred, envy, covetousness, and imperiousness as life-conditioning emotions, as factors which must be present, fundamentally and essentially, in the general economy of life (which must, therefore, be further developed if life is to be further developed), he will suffer from such a view of things as from sea-sickness.