Are metaphors elliptical similes?

What is the relation between metaphors and similes? Aristotle's "comparison theory" holds that metaphors are elliptical similes: "Sam is a pig" is sim ply a short form of "Sam is like a pig." In contrast, it has been suggested that metaphors cannot be elliptical similes because metaphors are "stronge r" than similes. We know metaphors are stronger, it is argued because of ex amples involving corrections. such as "Peter is not just like a rock he is a rock." The argument from corrections can be challenged on logical and emp irical grounds. The ability to correct a simile with a metaphor does not en tail that metaphors are stronger than similes when used on their own. which is likely to be the most frequent case. Although four experiments indicate that when corrections are involved, metaphors are indeed stronger than sim iles in several respects, alas a further four experiments indicate that the se differences are largely eliminated when metaphors and similes are used o n their own. We note that this pattern of results is consistent with the co mparison theory, and we offer an explanation of the effects of corrections.