… is from page 44 of Hayek’s The Trend of Economic Thinking (Vol. 3 of Hayek’s Collected Works); the quotation comes specifically from Hayek’s 1933 essay after which this volume is named:
The reason why I think that too deliberate striving for immediate usefulness is so likely to corrupt the intellectual integrity of the economist is that immediate usefulness depends almost entirely on influence, and influence is gained most easily by concessions to popular prejudice and adherence to existing political groups. I seriously believe that any such striving for popularity – at least til you have very definitely settled your own convictions, is fatal to the economist and that above anything he must have the courage to be unpopular.
