On Sameness and Identity: A Psychological Study Being a Contribution to the Foundations of a Theory of Knowledge — Themes and Context

Six Kinds of Sameness

Fullerton's central project is to distinguish what he calls the 'several senses' of the word 'same.' The excerpts do not enumerate all six, but they reveal his method. He contrasts a 'sameness in the strict sense, with no element of duality' against looser forms that allow for change or multiplicity. The stick seen straight in air and bent in water is 'the same stick in sense third'—a sameness that embraces a series of experiences rather than a single unchanging identity.

This taxonomic approach is not merely linguistic. Fullerton argues that philosophical disputes—from ancient scepticism to medieval scholasticism—arise when thinkers unconsciously shift between these senses. The sceptic, for example, 'confounds the first kind of sameness with the third,' demanding a strict identity that no physical object can supply. Fullerton's remedy is to make the ambiguity explicit, so that each sense can be evaluated on its own terms.

Pyrrho and the Problem of the Real Stick

Fullerton devotes a substantial passage to Pyrrho the Sceptic, using him as a foil for his own position. Pyrrho, he writes, correctly sees that a stick seen near at hand and a stick seen at a distance are both 'experiences'—neither differs in kind from the other. But Pyrrho errs, Fullerton argues, by insisting on a 'real stick' that could be captured in a single experience. The real stick, Fullerton counters, 'may be the name of the whole series of experiences in their appropriate relations.'

This is a key move: Fullerton rejects the demand for a strict, undivided identity and instead locates sameness in the ordered grouping of experiences. He accuses Pyrrho of wanting 'a sameness in the strict sense, with no element of duality'—a demand that no physical object can meet. The battle, Fullerton concludes, is between 'stick as a single experience, and stick as a group of experiences.'

Universals and the Scholastic Labyrinth

Fullerton hesitates to enter the 'labyrinths of the scholastic philosophy,' but he does so briefly, treating the dispute over universals as 'at bottom, a quarrel concerning samenesses.' He sketches Plato's view that the universal is a real thing apart from individuals, and Aristotle's rejection of that separation. The excerpts break off before Fullerton gives his own resolution, but the context suggests he will apply his taxonomy of sameness to clarify what is at stake.

The passage is notable for its restraint: Fullerton does not claim to solve the medieval debate, only to reframe it. His language is careful—he speaks of 'the object of the general term or class name'—and he avoids taking sides. The reader is left to infer that Fullerton's six kinds of sameness might dissolve the dispute by showing that each side is using 'same' in a different sense.

Fullerton's book is not a general theory of knowledge but a targeted analysis of a single word. Readers should expect close reasoning, frequent reference to historical philosophers, and a method that proceeds by classification rather than argument. The excerpts suggest that Fullerton is more interested in clarifying confusion than in advancing a positive doctrine. Those who enjoy precision and the dissection of conceptual puzzles will find the work rewarding; those seeking a sweeping epistemology may be disappointed.

I’ve always treasured how Fullerton untangles the word "same," finding six quiet doors where most see one. It reminds me of that old ethics volume, wrestling with truth’s stubborn heart. Both books share a gentle patience, a willingness to sit with a question until it breathes. I often shelve them together—A Lie Never Justifiable: A Study in Ethics — A Reader’s Guide—two old friends whispering about the weight of a single honest word.