A Cognitive Semantics Approach to Darwin’s Theory of Evolution

9 1. Theoretical Background: Cognitive Semantics storm as a recession)” (2007: 191). Similarly, a person’s affectionate disposition can be described in terms warm, but a warm blanket cannot be said to be affectionate. Another constraint on metaphorical mappings is called the I n v a r i a n c e P r i n c i p l e , which requires that metaphorical mappings preserve the cognitive topology (that is, the image– schema structure) of the source domain, in a way consistent with the inherent structure of the target domain. What the Invariance Principle does is guarantee that, for container schemas, interiors will be mapped onto interiors, exteriors onto exteriors, and boundaries onto boundaries; for path-schemas, sources will be mapped onto sources, goals onto goals, trajectories onto trajectories; and so on. (Lakoff 1993: 215) A consequence of the Invariance Principle is, as Lakoff further observes, that “image–schema structure inherent in the target domain cannot be violated, and that inherent target domain structure limits the possibilities for mappings automatically” (1993: 215). The limiting role of target domain structure is explored later in the context of metaphors of evolution. It is argued that scientific metaphors provide interesting data concerning how the Invariance Principle operates. While everyday domains such as life, love, time, economy, politics or actions are admittedly non-perceptual and vague, we nevertheless have some kind of experience with these, and that experience puts limitations on the possible mappings. For instance, to use Lakoff’s (1993) example, we can use the metaphor actions are transfers as in He gave me a kick, without inferring a transfer of possessions. In contrast to such common metaphors, target domains in science comprise concepts (e.g. atom structure, electricity, natural selection, etc.) which not only are abstract, but which also represent theoretical constructs. This means that when a theory is framed for the first time and/or is communicated to the general public, there is little knowledge of the structure of the target domain that could constrain metaphorical mappings. The Lakoffian Invariance Principle focuses on the preservation of image-schematic topology in metaphorical mappings. Krzeszowski (1997) suggests a modification of this term into the Axiological Invariance Principle to capture the fact that image schemas exhibit a plus–minus parameter, or axiological charge, which is preserved in metaphorical mappings. For example, the up–down schema, experientially grounded in the canonical form of the human body and its functioning, has a positive/plus value attached to up orientation and negative/minus value attached to down orientation. For