Thinking about it, your light source(outside) is the sun. If you take a measurement and go 5, 50 feet or 50 miles the distance hasn't really changed.
And you do not have to be near the subject, just in the same light. So, if you're at the rim of the grand canyon & take a reading, the exposure will be the same on both sides.
Assuming no clouds or shadows or solar eclipse or errant asteroid or something else like falling into a black hole just south of Dallas.( I know it's not nearby!)
When you're using an incident reading you're not reading reflected light, that's what a spot meter or reflected light meter does. Point the meter at the subject.
Incident reads the light falling on the subject.
The inverse square law is pertinent to (generally) a point light source. Flash, street light, spotlight table lamp. etc. Whether you use either kind of meter.