Paul Schlyter wrote:
On Wed, 1 Nov 2017 14:22:37 -0000 (UTC), Mike Collins
wrote:


Left and right are subjective. From the

No, they are not. You cannot consider left to be right, or up, or
forward, just because you feel like doing so. Left and right are
objective, but they are in relation to one person's body. So left and
right are objective, and personal. Just like starboard and larboard
are objective and in relation to the body of not a person but a ship.


Port and starboard are defined by the forward motion of a ship, otherwise
the red or green lights would have to be exchanged every time a vessel
changed from forward to reverse.
Left and right are much more vague. When two people are facing each other
you need to qualify to avoid ambiguity by saying “My left” or “Your left”.

The unremarkable clunky software Oriel is using to show the zodiacal motion
of the sun (I wrote better software than that in the 80s on a BBC micro) is
oriented with North at the top. If south were at the top the constellations
would move in the opposite directions.
Left and right are not precise enough to describe the motions of celestial
objects if you want to apply the description to the whole of the Earth. I
actually found it disconcerting in New Zealand to be walking in the
direction I knew was north while my instinct told me I was walking south.