 Without challenging these existing explanations involving Peirce’s EG, in this entry we would like to bring in one overlooked but crucial aspect of Peirce’s journey to EG so that our story may fill in part of the puzzle of Peirce’s overall philosophy. Peirce’s mission for a new logic started with how to represent relations, which led him to invent quantifiers and bound variables, as we discussed in the previous section. The same commitment, that is, to represent relations in a logical system, we claim, was a main motivation behind Peirce’s search for a new kind of sign systems—iconic representation of relations. Peirce’s work on Euler/Venn diagrams provides us with another piece of evidence to support our claim that the main motivation behind EG was to represent relations. While improving Venn systems, Peirce realizes that the following defect cannot be eliminated: