The most consequential thing about Mercury in a chart is where it stands with respect to the Sun, because it can never stand far. Mercury's greatest elongation keeps it within about twenty eight degrees of the Sun, so it is always in the Sun's sign or one of the two adjacent, and often inside the Sun's beams.
The tradition builds a whole vocabulary on that fact. Mercury rising before the Sun is oriental, the morning star condition, and is read as a mind that runs ahead of the will, quick to formulate. Mercury setting after the Sun is occidental, the evening star condition, and is read as a mind that follows and reflects. Mercury within about eight and a half degrees of the Sun is combust and held to be badly weakened, its light swallowed. Mercury within about seventeen minutes of arc of the Sun's body is cazimi, in the heart of the Sun, and is held to be at its strongest of all.
Those two extremes sit less than a degree apart in the sky and opposite in judgement, which makes them a good test of whether a reader is following the tradition or improvising. There is no smooth gradient here. The doctrine holds that a planet destroyed by proximity is exalted by absolute proximity, and the authorities state it that way without softening it.
Sect enters again. Mercury takes the sect of whichever side of the Sun it falls on, so the same degree in a day chart and a night chart is not the same placement, and a description of intelligence that ignores this is describing half of what the technique claims to see.