The human mind constructs an understanding of its sensory experiences by
fashioning a MODEL consisting of "objects" (Aristotle's "substances") and
their "properties" (Aristotle's "accidents").
So my major comment is that it is all "subjective". I take your question
"to exist or not to exist" to be concerned, not directly with external
reality, but with the physicist's MODEL of reality. We construct and define
into existence the objects, and their properties, comprising that model.
Consider how different must be the "reality models" of a congenitally blind
person vs. those of a sighted person. (Try to conceive a non-visual concept
of the "shape" of an object. Consider how the congenitally sightless
observer might puzzle over our distinction of the "reality" of matter vs.
field, etc.)
Bob Sciamanda
Physics, Edinboro Univ of PA (Em)
-----Original Message-----
From: Ludwik Kowalski
Sent: Saturday, February 02, 2013 7:14 PM
To: phys-L new
Subject: [Phys-L] To exist or not to exist
The short essay below was inspired by recent exposures. Comments will be
appreciated.
Our material world is made of physical objects; anything that has a certain
mass, and occupies a certain volume in space, is an object. Some objects,
such a stars and galaxies are very large, others, like electrons and
molecules, are very small. Collections of objects, such as airplanes, cell
phones and molecules, are also objects. The same is true for a certain
amount of water, or air, and for living creatures. To avoid confusion,
objects are named. Existence of objects is recognized by using our senses,
directly or indirectly, for example, with glasses, telescopes, microscopes,
Geiger counters, antennas, etc.
But not all names used by physicist refer to objects; some concepts, such as
force and acceleration, were invented to describe and understand behavior of
objects. Does kinetic energy exist in the same way as a moving car? I do not
think so. Energy, like force and acceleration, is a physical quantity
invented to describe and understand objects. Such theoretical quantities
exist in our mind; they do not exist objectively, like physical objects in
our material world.
Theoretical reality is subjective; physical reality is objective. It is not
difficult to imagine a planet on which material world phenomena have been
successfully described, and understood, in terms of theoretical concepts
that are different from ours. Many misunderstandings would be avoided if the
verb 'to exist' were always qualified. To "exist subjectively" is not the
same thing as to "exist objectively." Do you agree?