We commonly think of metaphor as something like analogy. We are trying to explain something to someone and we say this something new is very much like this other something you are familiar with.
This is one form of metaphor but there is another metaphor that is automatic and unconscious. The child playing with objects has an experience of collecting objects in a pile. This experience results in a neurological network that we might identify as grouping. This neurological structure that contains some sort of logic related to this activity serves as a primary metaphor.
The child has various experiences resulting from playing with objects. These experiences result in mental spaces with neural structures that contain the logic resulting from the experience. When the child then begins to count perhaps on her fingers these mental spaces containing the experiences automatically map to a new mental space and become the logic and inference patterns to make it possible for the child to count because counting contains similar operations.
Primary metaphors are the contents of mental spaces developed in experience and the contents then pass to another mental space to become the bases for a new concept. The contents of space A is mapped to space B to then be the foundation for the new concept at space B. This mapping is automatic and unconscious.
Many years ago, before