Re: Defining "physical"


"Paul Holbach" <paulholbachDELETETHENAME@xxxxxxxxxx> wrote in message
news:1194193674.175563.109580@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On 3 Nov., 16:20, "Dirk Van de moortel"
<dirkvandemoor...@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

Ask a physicist. He will tell you that if you can measure it,
it is physical.

"The properties of a physical system are represented by the values of
physical quantities: temperature, electric field, stress, etc. Crudely
speaking, a physical quantity is anything that can be measured. A
physical quantity is defined by prescribing the experimental procedure
that will measure it."

(Tarantola, Albert. /Elements for Physics: Quantities, Qualities, and
Intrinsic Theories/. Berlin: Springer, 2006. p. 105)

"PHYSICAL QUANTITY:
A physical property characterizing some aspect of Nature that can be
measured."
(www.ac.wwu.edu/~vawter/PhysicsNet/ProblemSolving/PhysQuantities.html)

All physical quantities are physical properties, but are all physical
properties physical quantities?
For example, the property of having a location in spacetime is
arguably a physical property, but not a physical quantity. There is no
such thing as the magnitude of a location (or position), which could
be measured.

Furthermore, psychologists measure intelligence, but intelligence can
hardly be called a physical property.

This means that the definition of "physical property" as "measurable
property" is inadequate.

One of my favorite quotes which I largely adhere to is

"Physical concepts are free creations of the human mind, and are not,
however it may seem, uniquely determined by the external world." - Albert
Einstein

Pete


.

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