The problemMental imagery, the process by which people conjure and think with images not immediately drawn from their senses, has been a point of contention in the field of cognitive science for some time. The question, in its most general sense, is whether or not people use mental images as a way of thinking about problems and arriving at solutions. As in many areas of cognitive science, philosophers, psychologists, and thinkers have wrestled with how the mind works with images for thousands of years, and there is still no firm consensus on the topic. More recently, scientific experiments have managed to shed a lot of light on how the brain works and the ways in which it is functionally divided. More and more is being learned about the detailed workings of the mind, and this has allowed for greater precision and scrutiny of theories advanced about the use of mental imagery as an element of human cognition. As a result, the question of mental imagery has increasingly shifted from a question of feasibility to a question of implementation and pervasiveness of this form of thinking. How does the brain deal with what we would call mental images? How similar to a perceptual image is a mental image? These are the questions that are posed today by modern theories of mental images. Alternatives The first theory to be examined is that there is no mental image to speak of, that mental image plays no role in human cognition, and that, regardless of the underlying postulated explanatory mechanism, humans do not make use of mental images. The second theory is that humans think only through mental images, to the exclusion of all other forms of thought. Like the first, this theory adopts a......center of paper thinking and coherence. M.-L. Dalla Chiara et al (eds.), Logic and scientific methods. Dordrecht: Kluwer, 413-427. Retrieved November 21, 2008, from http://cogsci.uwaterloo.ca/Articles/Pages/%7FAbducing.htmlGanis, G., Thompson, WL & Kosslyn, S.M. (2004) Brain areas underlying visual mental imagery and visual perception : an fMRI study [electronic version]. Cognitive Brain Research 20:226-241Pylyshyn, ZW (2002) Mental imagery: in search of a theory [Electronic version]. Behavioral and Brain Sciences 25:157–238Marr, D. & Nishihara, H.K. (1978) Representation and recognition of the spatial organization of three-dimensional shapes [Electronic version]. Proc. R.Soc. London. B. 200:269-294Kosslyn, SM & Thompson, WL (2003) When is the early visual cortex activated during visual mental imagery? [Electronic version] Psychological bulletins vol. 129, n. 5:723-746