This article explores the intellectual life of Max Harold Fisch, the twentieth-century American scholar of Giambattista Vico and Charles S. Peirce. Fisch was a thinker with fundamental commitments to both history and philosophy. The claim here is that his life exemplifies a constitutive tension in the work of intellectual historians, who operate in the interstice between these two disciplines. What we learn is that intellectual historians may have a double investment both in the filigree of particular historical contexts and in the principles that emerge in and then detach from those contexts. The article explores this double investment by following it through five decades of Fisch’s intellectual labor between 1930 and 1980.