Let us finally turn to the question of the identity of a musical work during a specified period in our historical time. This problem arises especially in longer periods that include a succession of different styles and even perhaps of fundamental ideals concerning musical and artistic aspirations. Old works live, that is, they are played and heard, in new musical epochs and while they are differently interpreted, they are, nevertheless, regarded as being the same as they were in the past, although they used to be played in different ways. In order to appreciate fully the difficulties arising when we wish to confirm our conviction regarding the identity of musical works that sometimes stay alive over a number of centuries, we first have to bring the problem into sharper focus. In the existing formulations of the problem of a musical work's identity, the term "musical work" remains ambiguous. Second, the formulation of the problem suggests two approaches that need to be clearly distinguished: a purely ontological or ontic formulation of the problem and an epistemological or an aesthetic formulation. Finally, we need to stress that the question can be variously formulated, depending upon the method of "fixing" a musical work.