Hello, my question(s) is: could emotions, concepts and physical things that are

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Hello, my question(s) is: could emotions, concepts and physical things that are opposite to each other, exist without each other? For example, if there were no such thing as hot, then could cold exist? What about joy and sorrow? Could we identify one without the other? Do they require our awareness of them, for them to exist? Obviously this isn't the case with some things, like gravity.