| Two fundamental views about the nature of visual mental images have played significant roles in both the history of philosophy and the history of psychology. The traditional, or imagist view, is that mental images are like inner pictures. Experiencing these inner pictures is understood to be something occurring in the absence of a physical stimulus, but is also acknowledged as something significantly like seeing actual objects. This often leads to attributing to mental images the actual properties of physical objects and to postulating an inner homunculus that can observe these properties. Recognition of these difficulties led to the descriptivist view, which holds that mental images are actually inner verbal descriptions. Descriptivists argue that mental images, like physical images or pictures, carry no meanings in and of themselves. They are therefore incapable of performing any of the functions in the mind traditionally assigned to them by imagists, such as bearing memory information or serving as abstract general ideas (e.g., as in Locke's philosophy).; I argue for a compromise position between the two views. After reviewing the history of mental imagery, I argue that having mental images is a complex family of states, each of which involves varying degrees of visual and intentional (or conceptual) content. At one end of the scale (after-images), mental images may have virtually no conceptual content; at the other end of the scale (thought images), images may serve as symbolic quasi-instantiative particulars in and through which we think. Although they obviously do not have the properties of physical objects, I maintain that phenomenological and linguistic analyses identify mental images as objects, and that there are no metaphysical bars to admitting mental objects as real entities. By means of contrast, I also investigate how two contemporary theories in cognitive science understand mental imagery. I suggest that the hypothesized computational states and procedures meant to reveal the nature of mental imagery lead to untenable views about the mind, and tell us very little about mental images. |
