Quote Originally Posted by Staurm
Abstract models, mathematics (although arguably that WAS there in the first place), atoms, particles, waves, photons, viruses, strings, dimensions, time dilation, spatial contraction, 3 dimensional probability density functions, black holes, galaxies, dark matter, light.
Atoms are observable.
Atoms are particles, therefore "particles" are observable.
Waves are observable.
Photos are observable.
Viruses are observable.
String theory is a theory.
Dimensions are observable (at least the 3 we're able to discern, plus time if you count it as a dimension)
Time dilation is observable and confirmed
Black holes can be inferred to exist. Just because we can't see them (by definition, since they also trap light), doesn't mean they exist. Like air, we can't see it yet we breathe, and it's measurable.
Dark matter is a theory but there is very strong evidence it exists.
Light is observable

I'm not sure what your point was tho..