called ‘thinking’. Sometimes, surely, our thoughts can consist in a mixture
of sentences and mental images. Thus, when reasoning about some prac-
tical problem, I might entertain a mixed thought like the following: ‘If I put
this stool on the tablelike so[insert image], then by climbing on top of it I
shall be able to reach uplike that[insert image].’ (Note that we do not
mean to beg any questions about thelanguage in whichsuch a thought is
partly entertained. The non-imagistic components of the thought might
very well be expressed in Mentalese, for all that we mean to imply here.)
Moreover, sometimes our conscious thoughts can consistentirelyof im-
ages of objects (and not of images used as conventional symbols). The
thoughts of composers may sometimes consist entirely of auditory images,
as they manipulate images of melodies and chord patterns, trying out
diVerent possibilities until hitting upon something which satisWes them.
The thoughts of an engineer, or of someone trying to pack a set of suitcases
into the luggage compartment of a car, may consist entirely of visual
images of arrangements of objects. And someone’s thoughts as she tries to
Wnd her way round a room in the dark might consist simply in an evolving
image of the room’s layout in egocentric space, becoming updated in
accordance with her movements.
Our focus in this chapter, however, will be exclusively onpropositional
orfully conceptualthinking – that is, on the kind of thought whose content
may properly and correctly be described by means of a propositional
that-clause. Many of us feel intuitively that our imagistic thoughts are not
properly described in the that-clauses which we are forced to use if we want
to express them in language. For example, if I have been planning my route
from my home to the railway station by mapping it out in my head, using
an image of the layout of the city, then I would feel pretty lame to have to
describe that thought by saying, ‘I was thinking that I should start towards
the city centre, and then turn right.’ For this does not begin to approximate
to the richness of what I had actually thought. Moreover, as we pointed
out above, mental images cannot begin to capture the content of even a
relatively simple proposition such as, ‘All grass is green.’ This suggests that
there exist two distinct kinds of thinking – imagistic thinking, on the one
hand, and propositional thinking, on the other.
It can be disputed just how distinct these forms of thinking really are.
In particular, cognitive psychologists argue about whether visual images
are picture-like, carried by representations with the analog properties of
maps, or whether they are description-like, being subserved by complex
descriptions of their subject matter. This is the dispute betweenpictorial
anddescriptivisttheories of the nature of mental images. (See Tye, 1991,
for an account.) This is not a debate we propose to join. We shall con-
Wne our attention to those forms of thought which are
Preliminaries: thinking in images 193