Exactly my point! Defining a duck by saying it is a thing that looks and quacks like a duck and can be used to do duck things does not actually define a duck!
It's the difference between describing what something does and defining something. If I had asked 'what is light' then answers that would tell me how to measure its intensity, describing how it can illuminate things or be used as a laser would not be as defining as say, Maxwell's equations...
Thank you DaleSpam. Your references have underlined the fundamental problem. They all give mechanical definitions of work/energy (ie the observed effects of energy and how to calculate the amount) or define energy tautologically by saying that energy is different types of energy (a rhododendron...
Thank you mfb, but that seems like an almost Zen-like answer! The extrapolation is that matter is then also a model so all we are left with in the Universe is Space-Time and Observations, which I guess could be a neat marriage of Relativity and Quantum mechanics :-)
It does lead though to a...
We have many different ways of describing and quantifying 'energy' eg kinetic, potential etc. We also know that mass and energy are equivalent. We intuitively know what it does and we talk about it across many fora but my question is 'What is Energy?'. What is this characteristic of the universe...
The problem is almost one of semantics. We often consider this as a a photon being like a classical billiard ball when we all about acting as a particle and then like a wave on water when considering the wavelike action. The 'reality' (whatever that is) is that the concept that we have of a...
There are many quotations from the 19thC referring to the 'fact' that science was nearly complete except for a few minor bits to tidy up.
Is it possible then, that Dark Matter and Dark Energy are actually pointing to a 'new' physics where the Standard Model is a special-case subset of the...