Aristotle disagreed with Plato on this point, arguing that all universals are instantiated at some period of time, and that there are no universals that are unattached to existing things.
ˈæɹɪstˌɑːɾəl dˌɪsɐɡɹˈiːd wɪð plˈɑːɾoʊ ˌɔn ðɪs pˈɔɪnt, ˈɑːɹɡjuːɪŋ ðæt ˈɔːl jˌuːnɪvˈɜːsəlz ɑːɹ ɪnstˈænʃɪˌeɪɾᵻd æt sˌʌm pˈiəɹɪəd ʌv tˈaɪm, ænd ðæt ðɛɹˌɑːɹ nˈoʊ jˌuːnɪvˈɜːsəlz ðæt ɑːɹ ʌnɐtˈætʃt tʊ ɛɡzˈɪstɪŋ θˈɪŋz.