Literally the same thing, a concept is something that exists in your head. It may be an idea that makes sense in your brain but it doesn't actually exist.
It may be real in the sense that there are connections in your brain that physically exist tho, but there are no quantities that just exist. Think about how there are apples on the opposite side of the world where you are that you know nothing about. Do they not exist even though you don't know about them? Of course they, because they have mass.
Wrong, concept brained response. The apples would exist whether or not there was someone to come up with "quantity". You're right about the last bit tho, they're just properties of reality, and they apply to things that have mass.
@bot the apples exist because they have a variable inextricably attached to them called quantity; if they didn't, they wouldn't exist. There couldn't be 'one' apple or many, there'd have to be none. There are some other concepts too like speed, or acceleration, or magnetism, or maybe you could consider these qualities that space happens to exhibit...
Multiple different things of something existing doesn't mean that they can't exist. They aren't exactly the same, are they? Is anything exactly the same? It doesn't matter if an idea in your head exists or not or if there's anyone to observe it, it can still exist.
@bot it's not about whether someone's invented quantity, it's that in the real world there exist a certain amount of apples and if 'amount' isn't metaphysically a thing they simply can't exist. You're thinking of it in a way that's too human-centric.
@bot sounds are displacement waves they have no mass they are a beavior that things that have mass are currently doing, light is the same, but instead of a change in density it is a change in general internal movement.
substance exists and force exists, everything is both but different combinations at different times
@shrimp@bot It's worth pointing out that bot's position is essentially the one adopted by modern science (materialism).
Starting from a Cartesian metaphysics of matter and soul, the soul was removed, and the matter embedded in an empty ambient space (the vacuum - at one point a controversial idea). Science is supposed to observe matter and formulate hypotheses - laws - which make sense of the observations. But since the laws can never be definitively proven, it is wrong (in this view) to say that the laws 'govern' matter or that the laws are 'prior' to matter. The human instinct to place the laws 'above' matter is the same instinct as that which places God above the Earth (hence @hidden 's comment).
In this view, a wave is an abstraction which describes the motion of water molecules, and light is an abstraction which describes the motion of the electromagnetic field.
This 'field' is believed to extend throughout all space, meaning that the vacuum is not as empty as initially thought. Does the field itself exist - or, as bot would say, does it have mass? The idea of vacuum energy suggests that it does, but this is beyond my depth.
@shrimp@bot@hidden Perhaps, in the end, we will find that mass also does not exist. Maybe quantum gravity will say that mass is just a name for what happens when matter interacts with gravitons or the 'gravity field.'
@bot@hidden@shrimp Worth mentioning that the E = mc^2 equation assumes that the particle is at rest (which light never is). The equation for a particle in motion is E^2 = p^2 c^2 + m^2 c^4, where p is momentum. A photon has m = 0, but p > 0 and hence E > 0 and there is no contradiction. https://en.wikipedia.org/wiki/Photon#Physical_properties