Question: I'm looking to find some resources to read about the following:  

When we talk about a general concept (the word pencil in "a pencil is made of wood"), we actually have a mental image of a **particular** object in our mind (a particular pencil with a particular color in the example).

I'm looking to read about this and similar issues. I don't even know what topic to look into. I've looked a bit on Frege's work but I didn't find what I was looking for. I'd appreciate suggestions.

Answer: 
The interval of a second is currently defined as exactly 9 192 631 770 cycles of a Caesium atomic clock. Furthermore the definition has changed several times.

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> <https://en.wikipedia.org/wiki/Second>
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From this we see that: 1. The interval of a second is completely arbitrarily chosen. 2. Scientists take great care to construct high precision *relative* time scales. This brings us to how Science sees the *time dimension*: 

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> <https://en.wikipedia.org/wiki/Spacetime>
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Relativity theory tells us that time is integral to the fabric of "Reality". That is, any measurements an *Observer* makes must be done in *four dimensions*. 
Now we can say that: 1. Scientifically speaking a time interval can only be said to be real when observed, with an appropriate *external* time scale. But, 2. An Observer independant Spacetime interval underlies Special relativity.

From 1. we would say that indeed there are no time elapsed between A and B. However from 2. there is a mathematical abstraction that could correlate to and independent spacetime.

But wait there is more: 

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> <https://en.wikipedia.org/wiki/Quantum_nonlocality>  
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> <https://en.wikipedia.org/wiki/Quantum_entanglement>
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Taking Quantum and Relativity together we also find, 1. not only an isolated system for A and B, but the whole universe must be without events in order to have a truly Timeless interval. However it is unclear whether the previous sentence is *even valid* because of a) the large areas of discord between Quantum and Relativity theories and b) the different interpretations of Relativity, and especially Quantum, theory.

**Philosophic implications**

There are no consensus among philosophers-of-science about the true nature of time. But from a Physics standpoint Time does not exist independently of Space, and some would add Observers.
It depends.

If nothing is changing because in fact there is nothing there then it's right to say that no time is passing because there is nothing there including time. 

If nothing is changing because everything is actually in stasis but could potentially change then time is passing.

If nothing is changing because everything is actually in stasis and cannot even in principle change then time is not passing because time is the potential for change.

If nothing significant is changing then time is still passing.