Updated: Jan 11, 2021
Before we talk more in detail about phrasal verbs, let's talk about space. Not Outer Space, but the space around you and me - the three-dimensional space we move in every day. Langacker (1986) theorized that "all grammatical units are symbolic"(p. 1) and relate to conceptualizations of the mind. For this reason, Space Grammar is also called Cognitive Grammar because it assumes that meaning is equated with conceptualization (Langacker, 1986)
Human beings have an amazing ability to combine two or more conceptualizations to form richer and more complete idea. Take these two fundamental concepts (Langacker, 1982): your sense of color, and the concept of a cat: [PURPLE] + [CAT]... and voila. You have likely just conceived a creature never before seen to man....except perhaps in the movies.
Phrasal verbs work in a similar way. Let's take a fairly concrete phrasal verb:
[MOVE] + [UP] = go in a vertically higher direction.
From there, our brains have figured out how to apply this concrete meaning to abstract ones through METAPHOR...more on this in another post.
Langacker, R. W. (1982). Space grammar, analysability, and the English passive. Language, 22-80. https://www.jstor.org/stable/413531
Langacker, R. W. (1986). An introduction to cognitive grammar. Cognitive science, 10(1), 1-40. https://doi.org/10.1016/S0364-0213(86)80007-6