This paper reconstructs Venn’s algebraic logic and identifies some of the philosophical notions concerning the nature of symbolic knowledge underlying his work. We show that Venn, in facing philosophical problems associated with his algebraic logic, needs to articulate the symbolic knowledge notions of ecthetic function and of surrogative function. The paper explains those notions based on the systematization of the functions of symbolic knowledge that we find in the recent philosophical literature. This paper also situates Venn’s work within the 19th (...) Century efforts towards a symbolization of logic, and, through an analysis of a historical case, clarifies the notions of ecthetic function and of surrogative function. (shrink)

a single life-span. Philosophers, then, do not see more or know more, and they do not see less or know less. They aim to see less detail and more of the abstract. Their details, if you like, are abstractions. Walking on God’s earth as a pedestrian, as a farmer working his fields or as a passer-by, one’s picture of one’s surroundings is every bit as intelligent as that of the pilot riding the sky. The views of the field are radically (...) different, however. One sees only a specific field and in all lively detail: the exact pattern of the land, or even the exact outline of a given leaf, grasshopper, grain of sand even. Acquaintance with minute detail is not without its price: details may stand in the way of conjuring the big picture. It may be difficult to compare whichever field one happens to be in with far off fields, with respect to their size or shape or any other quality. One may wish to inquire if far off fields were already planted, harvested, or even if they exist. A pedestrian may find it hard or even impossible to do so. The pedestrian view contains fine points that the pilot’s map never would, but it does not necessarily contain more information, for it lacks the general context. After all, there are only so many items that one can observe and account for at a single glance, a single map, a single book, a single life-span. (shrink)