java This cannot be referenced from a static context cannot be referenced from a static context

Question

i tried to abstract my code a little bit and i got over a error i dont know to handle

public interface Manager<T extends Member> {
    Set<T> member = new HashSet<>();

    default Member getMember(String name){
        for(T m : member){
            if(m.getName().equalsIgnoreCase(name)){
                return m;
            }
        }
        return null;
    }
}

now when i hover over the T in Set i get "Manager.this cannot be referenced from a static context". i really have no clue why.