JargonFile/entries/logical.txt

logical

adj. [from the technical term logical device , wherein a physical device is
referred to by an arbitrary logical name] Having the role of. If a person
(say, Les Earnest at SAIL) who had long held a certain post left and were
replaced, the replacement would for a while be known as the logical Les
Earnest. (This does not imply any judgment on the replacement.) Compare
virtual. At Stanford, logical compass directions denote a coordinate system
relative to El Camino Real, in which logical north is always toward San
Francisco and logical south is always toward San Jose--in spite of the fact
that El Camino Real runs physical north/south near San Francisco, physical
east/west near San Jose, and along a curve everywhere in between. (The best
rule of thumb here is that, by definition, El Camino Real always runs
logical north-south.) In giving directions, one might say: To get to Rincon
Tarasco restaurant, get onto El Camino Bignum going logical north. Using the
word logical helps to prevent the recipient from worrying about that the
fact that the sun is setting almost directly in front of him. The concept is
reinforced by North American highways which are almost, but not quite,
consistently labeled with logical rather than physical directions. A similar
situation exists at MIT: Route 128 (famous for the electronics industry that
grew up along it) wraps roughly 3 quarters around Boston at a radius of 10
miles, terminating near the coastline at each end. It would be most precise
to describe the two directions along this highway as clockwise and
counterclockwise , but the road signs all say north and south ,
respectively. A hacker might describe these directions as logical north and
logical south , to indicate that they are conventional directions not
corresponding to the usual denotation for those words.