In earlier times, identity was mostly a function of social relationships. This seemed to be a lot more concrete than abstract concept of identity that is popular in industrial societies.
Here are some other things that might inform/create identity besides political opinions shared on twitter: race, religion, ethnicity, nationality, gender, occupation, consumption preferences, skills, activities, appearance.
All of these are ideas to some degree, but some are more concrete than others. But ultimately, identity itself is an idea and I don't think it can be fully separated from other constructs of the mind.
If you ask me about my identity the first thing that comes to my mind is the life I've lived. The things I got to experience, my failures, my accomplishments, the choices I made.
Here are some other things that might inform/create identity besides political opinions shared on twitter: race, religion, ethnicity, nationality, gender, occupation, consumption preferences, skills, activities, appearance.
All of these are ideas to some degree, but some are more concrete than others. But ultimately, identity itself is an idea and I don't think it can be fully separated from other constructs of the mind.