If a heavy cannon ball (H) and a light musket ball (L) are attached to form a compound object (H+L), the compound must fall faster than the cannon ball alone because it is heavier (H+L > H).

What we term the “intuition–based account” of thought experiments comes in a naturalistic version (see Brendel 2004; Gendler 2007), and in a Platonic version (see Brown 1991a [2011]). We begin with a discussion of the latter. Brown holds that in a few special cases we do go well beyond the old empirical data to acquire a priori knowledge of nature (see also Koyré 1968). Galileo showed that all bodies fall at the same speed with a brilliant thought experiment that started by destroying the then r