reasoning, through the extension of spatial and physical laws to more complex situations. A primary tenet of this theory is that metaphors are matter of thought and not merely of language: hence, the term conceptual metaphor. The metaphor may seem to consist of words or other linguistic expressions that come from the terminology of the more concrete conceptual domain, but conceptual metaphors underlie a system of related metaphorical expressions that appear on the linguistic surface. Similarly, the mappings of a conceptual metaphor are themselves motivated by image schemas which are pre-linguistic schemas concerning space, time, moving, controlling, and other core elements of embodied human experience. Conceptual metaphors typically employ a more abstract concept as target and a more concrete or physical concept as their source. For instance, metaphors such as 'the days [the more abstract or target concept] ahead' or 'giving my time' rely on more concrete concepts, thus expressing time as a path into physical space, or as a substance that can be handled and offered as a gift. Different conceptual metaphors tend to be invoked when the speaker is trying to make a case for a certain point of view or course of action. For instance, one might associate "the days ahead" with leadership, whereas the phrase "giving my time" carries stronger connotations of bargaining. Selection of such metaphors tends to be directed by a subconscious or implicit habit in the mind of the person employing them. The principle of unidirectionality states that the metaphorical process typically goes from the more concrete to the more abstract, and not the other way around. Accordingly, abstract concepts are understood in terms of prototype concrete processes. The term "concrete," in this theory, has been further specified by Lakoff and Johnson as more closely related to the developmental, physical neural, and interactive body (see embodied philosophy). One manifestation of this view is found in the cognitive science of mathematics, where it is proposed that mathematics itself, the most widely accepted means of abstraction in the human community, is largely metaphorically constructed, and thereby reflects a cognitive bias unique to humans that uses embodied prototypical processes (e.g. counting, moving along a path) that are understood by all human beings through their experiences. Conduit metaphor The conduit metaphor is a dominant class of figurative expressions used when discussing communication itself (metalanguage). It operates whenever people speak or write as if they "insert" their mental