 Resemblance theories of depiction differ from one another in significant ways. But they agree on the following crucial point: the fundamental difference between pictorial and linguistic representation consists in the fact that the former depends on resemblances between representations and the objects they represent, whereas the latter does not. It is widely agreed that linguistic representation depends on conventions that create the vocabulary of a language and the semantically significant structures in which the elements of its vocabulary are combined. But the contribution words and structures make to the meaning of a sentence are hardly ever explained by resemblance. If there are exceptions, such as onomatopoeia, they confirm the rule.