How mental systems believe.

Is there a difference between believing and merely understanding an idea?Descartes thought so. He considered the acceptance and rejection of an idea to be alternative outcomes of an effortful assessment process that occurs subsequent to the automatic comprehension of that idea. This article examined Spinozas alternative suggestion that (a) the acceptance of an idea is part of the automatic comprehension of that idea and (b) the rejection of an idea occurs subsequent to, and more effortfully than, its acceptance. ideas is quite similar to the mental representation of physical objects: People believe in the ideas they comprehend, as quickly and automatically as they believe in the objects they see. Research in social and cognitive psychology suggests that Spinozas model may be a more accurate account of human belief than is that of Descartes. Though Truth and Falsehood bee Neare twins, yet Truth a little elder is.--John Donne, 1635/1930, p. 129 Everyone knows that understanding is one thing and believing is another, that people can consider ideas without considering them so, and that one must have an idea before one can determine its merit. Everyone knows the difference.., between supposing a proposition and acquiescing in its truth (James, 1890, p. 283). Nonetheless, this article suggests that what everyone knows may be, at least in part, wrong. It will be argued that the comprehension and acceptance of ideas are not clearly separable psychological acts, but rather that comprehension includes acceptance of that which is comprehended.