Is darkness a non-physical property?

DaveC426913 said:
No. The sky is blue due primarily to Rayleigh scattering - the tendency for bluer light to scatter more than red light due to the atmosphere. That scattering means that light that would otherwise go over our head, gets redirected toward us, and, since it's blue, it means we see a bluer sky.



From one narrow perspective, if that's the way you choose to interpret it.
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I don't think I said the top quote.

The bottom perspective is the LCH definition
 
TheVat said:
This might be one of those chats where phenomenology collides with scientific tries at objective description. Darkness seems to be phenomenal (something brains derive from perceptual inputs), but we try to take it beyond this abstraction and determine objective absences of, say, visible light, thus defining a phenomenon by its opposite. (we do this with "cold," too)

I could say for example that "scaryness" is a quantifiable, controllable, repeatable property of horror movies. We could measure galvanic skin response, pulse and perspiration during different movie scenes, correlate this with reported experiences of viewers being scared, and come up with a dataset of physiological changes that is then put under the phenomenal umbrella of scaryness. But when we're packing up the equipment and heading home, we can admit that scaryness, as an abstract way of speaking about scenes in fright flicks, remains in the phenomenological sphere and is not a more objective set of physical properties like, say, cinema projector photons passing through rectangular frames of film emulsion and bouncing off a phosphor screen 24 X/sec. into human eyes where they strike visual pigment molecules and trigger electrochemical signals through the optic nerve etc.

I think it's easy to get into what philosophers call category errors.

Category mistake - Wikipedia

en.wikipedia.org en.wikipedia.org

We don't find a chemist who will separate out all the compounds in paint and then produce one on a little sample tray and say "here is the darkness!" (or if she does, then we take it as metaphor, not a literal substance with the unique property of darkness)
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A chemist might talk of a high molar extinction coefficient, though. And I suppose a physicist might quantify how far from being a black body a given object is.

It seems to me we need to distinguish between darkness as an entity , which I think was the sense in which it was used in the OP, and darkness as a (relative) property of an object or environment. The latter seems to be what DaveC426913 has in mind and I’d agree that can be quantified scientifically, e.g. as I have indicated. The former, though, is more of a literary term, or a perception of human sensibility, and doesn’t have scientific meaning, other than absence of visible EM radiation.

Would that be fair?
 
DaveC426913 said:
Right. Because, as the argument has been going, it is a property of thing, not a thing itself.
You can't reduce a rock to say "here is the mass".

So I do not see how it is a category error.
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I was driving toward a semantic observation about what we mean when we say darkness (in a certain context, yes), as opposed to referring to more concrete properties like wavelength or molar absorptivity. Possibly I'm not really conveying my point well, so I will take a breather.
 
I would think that, in this case, darkness means the absence of visible light. But visible light is only a small portion of the EM spectrum and is variable by species.

By any measure I'd think that an absence of EM radiation is not a "property" of anything.
 
Morse code
Back in the day, between the dits and dah's, there was a ‘nothing’ of very great importance.
 
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