The article explores the semantics-pragmatics relations concerning metaphor interpretation in natural languages. We deal with the historical roots of metaphor founded in Aristotle, who emphasized that metaphor interpretation requires theknowledge of the external world. We present two formal semantics approaches to metaphor developed by Joseph Stern and Emma Borg. They both claim that successful metaphor interpretation needs the knowledge of extra-linguistic factors to supplement semantic knowledge. In conclusion, we define which of these two approaches is more consistent with Aristotle's view. The first part of the article is concerned with Stern's approach. He suggests a theory of metaphor developed in accordance with Kaplan's semantics, where we distinguish two levels of meaning, i. e. the character of the expression and the presupposing of the character - content distinction. The formal semantic theory of metaphor aims to define the rules for meaning assignment for metaphoric utterances. However, these formal rules only provide a universal form of interpretation for metaphoric utterances and do not explain the actual process of interpretation. In order to explain this process, we need to supplement semantics with pragmatic knowledge. The second part of the article deals with Borg's approach, which also presupposes that semantics is not enough to understand metaphor. In addition to semantic knowledge, one requires psychological knowledge, i. e. the knowledge of the structural relationships between concepts that reflect the structural relationships in the external world. Having psychological knowledge is what allows us to interpret metaphorical utterances. We argue that the main similarity between the two presented approaches lies in the fact that they both admit that having semantic knowledge is not enough for a successful interpretation of metaphor. The difference between the approaches is that Stern states that we need to add pragmatic knowledge, while Borg argues that we need the psychological one. We agree that Aristotle accepts isomorphism between language, thought, and the external world. Based on the fact that Borg implicitly accepts the weaker version of isomorphism, i. e. between thought and the external world, and Stern does not, we conclude that Borg's approach is more consistent with Aristotle's view.