Between cold and heat, extremes that seem to exclude one another. How packing a bag in a snowy city, you simply cannot imagine the torrid blast that will greet you as you step off the plane at your destination with a suitcase full of useless boots and sweaters and not a single short-sleeved shift.
Between sensation and pain, which is no doubt some sort of continuum with a variable threshold, thoroughly tangible and highly specific for each entity. Whenever you cross it (it does move around quite a bit) there is no doubt: pain is pain, when it's being pain, and not the same as sensation.
Between being alone or being with others, or among them. Though the with/among difference is, from certain angles, invisible. Another facet in which the presence of others becomes profoundly internal, asserting itself even when you're alone. Conversely, the sense of being so deeply alone that neither one nor a thousand bodies could change it.
Between driving and not-driving as something you are doing or not. Between a state of being driver or non-driver; or between not knowing how versus knowing how but not at the moment doing it because you're vstaying home or taking a cab, or maybe riding a bike, even.
Between writing: carried out sometimes in your head day and night for months on end but traceless to those around you except perhaps for that air of distraction, suggesting a faint bitterness on your part; an act so expensive and brutal it separates (temporarily) body from mind. And not-writing, an act so simple it isn’t worth mentioning. The chasm erased with a stroke of the pen.