Events

E. B. Holt’s dissertation, The Motor Element in Vision, earned him the PhD in 1901 for empirical
research he conducted at Harvard’s psychology laboratory under Hugo Münsterberg. Later
published in polished form as “Eye-Movement and Central Anaesthesia” (Langfeld 1946), the
work seeks to explain why visual awareness is suppressed during voluntary eye movement (more
precisely, during what today would be called voluntary saccades; Holt 1903). A pointed
illustration of this phenomenon had already been documented in the psychological literature by
the late 19th century: it is difficult, under normal conditions, to see your own eyeball move in a
mirror. Holt’s dissertation project is to experimentally isolate this phenomenon and then explain
why it occurs.

In this talk, I shall examine Holt’s experimental work, which is interesting for several reasons.
Holt is a founding member of the New Realists, and an important influence (along with James)
on Russell’s neutral monism. Although philosophers often think of New Realism and Russellian
monism as quite conceptual, we will find that these movements have at least one important root
in experimental psychology. In particular, I will show that Holt’s philosophical thinking about
the relationship between consciousness and the body (as exemplified in later works like Holt
1912, 1914) took early shape in the context of his experimental work. Second, Holt’s
interpretation of his own experiments explicitly appealed to Münsterberg’s “action theory” of
consciousness, which is a step more radical than James’s better-known work. In James’s catch-
phrase, “consciousness is motor,” the “is” is the is of predication, not identity (Klein 2025); but
Münsterberg argued that contents become conscious in virtue of stimuli getting connected in the
right way with motor discharge. Hence Holt’s experimental work can be understood as an
important step in the radicalization of philosophical and psychological views associated with
James’s early work on mind, moving such functionalist thinking down the path towards
behaviorism.