The perceptual contrast between being located inside vs. outside an enclosed space (area or volume) is used to represent a number of figurative contrasts. (Location is one of the five Concrete Organizing Notions of the MetaSelf model). Among these figurative meanings for a location are (a) Membership in a logical class or social class, (b) Situation or circumstance, (c) Role, (d) State, (e) Period of time.
(a) Membership and non-membership in a category, mathematical class, social group or class. We say something falls into a category or outside a category. The Latin prefixes in- and ex- are important linguistic markers. E.g., include/exclude.
The location that represents a class of members is like a space with one or more entrances or exits. Thus someone can have an "in" meaning that they know someone who can introduce them, or they have a quality that will engage the interest of the group or the person(s) who control admission to the group.
"Insider" and "outsider" are highly evocative terms. Insiders are supposed to be "in the know," which sounds positive, but they may also be seen as having an unfair advantage (Insider trading on the stock exchange). Outsiders are ambiguous, too, often being seen as being excluded and negative, but occasionally as having an objectivity or freedom not possesed by people who have a stake in their membership in a class or system. An outside observer of a family or business may be an "outside agitator" but may also make obervations and offer good advice because he or she is not so involved in the rewards and punishments of the system.
(b) Situation, position or circumstance. Being in a place (location) can be figurative for being in a situation or circumstance. We say "in the catbird seat" to mean being in an advantageous position. But, again, being in a place is not always positively toned. We also say "in a spot," "in a trap," and "in a fix." If someone finds a situation uncomfortable, they may want an "out," an excuse to leave.
(c) Role. If a situation (figurative position) is rather permanent, it can be seen as a role. A person can move in or out of a role, as if it were a space dedicated to a particular function or group of functions. Thus it seems quite natural to say, "When my mother died, my grandmother stepped into that role."
(d) State. Phrases that seem to suggest being in a place can stand for being in a state of some kind, as "in a coma," "in love," "in bankruptcy." Similarly, someone can be engaged in a process -- "in negotiations," "in transition," which often suggests figurative motion of some kind.
Within the law, outside the law. Within the rules, outside the rules. Within the bounds of polite society, out of bounds. The idea of a boundary appears to go back to the idea of binding things together, as if a string went around the outside of a parcel of land.
(e) Period of Time. A period of time is sometimes seen as a spatial volume in which one exists ("In the present day...," "In the future...") or through which one passes ("We will shortly be moving out of the twentieth century into the twenty first."). By contrast, time is sometimes pictured as moving while we are seen as standing still: "Your birthday has come and gone." Time passes by us, it flows like a stream or river. "In times gone by,..." As the song says, "Time goes by, so slowly..." The figurative motion in these cases allows us to characterize the future and the past in terms of the direction one is facing. "Looking forward to" means anticipation, "Looking back over" suggests remembering, reconsideration, or regret.
Inner/outer. Inward/outward. In literal space, the direction of motion going into or out of a space or location. Figurative motion is often implied by this contrast. For example, "the outward show of affection" suggests, if not actual affection radiating from a source inside a person, at least the appearance of affection coming off their surface. The person is supercially affectionate. Similarly, the line of sight of someone looking at the person is treated as figurative motion, although there is no motion outward from the self.
The contrast between someone's true personality and how one appears to others: "my inner nature" vs. "to outward appearances." The "inner child" is a way to name feelings, needs and potentials, which one may have repressed, putting them in the figurative space we call the "shadow" or the unconscious.
Phrases that counter this contrast:
Straddling, interconnected, bridging; on the edge, border, fence, or threshold.