"10" is the representation of a data; "0xA" is another representation of the same data.
Not being able to touch something doesn't make it an abstraction. Light is not an abstraction, a contract is not an abstraction. 10 is not an abstraction, it is an ordinal [1].
"Isomorphism" is an abstraction. It doesn't name a particular data or value, but a class of functions that share common properties. A function template or functions written in a dynamically typed language can describe a particular group of isomorphism.
> Light is not an abstraction, a contract is not an abstraction. 10 is not an abstraction, it is an ordinal [1].
It seems to me that all of those things very much are abstractions. They are not the utmost level of abstraction, but they are abstractions!
(Actually "a contract," which at first I thought was the clearest win, I'm now not sure about. On reflection, it seems like a concretization, turning abstract ideas of trust and reliability into concrete conditions under which the contract has or has not been met.)
"10" is the representation of a data; "0xA" is another representation of the same data.
Not being able to touch something doesn't make it an abstraction. Light is not an abstraction, a contract is not an abstraction. 10 is not an abstraction, it is an ordinal [1].
"Isomorphism" is an abstraction. It doesn't name a particular data or value, but a class of functions that share common properties. A function template or functions written in a dynamically typed language can describe a particular group of isomorphism.
[1] https://en.wikipedia.org/wiki/Set-theoretic_definition_of_na...