ɪn ˈæɹɪstˌɑːɾəlz tˌɜːmɪnˈɑːlədʒi, "nˈætʃɚɹəl fɪlˈɑːsəfi" ɪz ɐ bɹˈæntʃ ʌv fɪlˈɑːsəfi ɛɡzˈæmɪnɪŋ ðə fɪnˈɑːmɪnə ʌvðə nˈætʃɚɹəl wˈɜːld, ænd ɪŋklˈuːdz fˈiːldz ðæt wʊd biː ɹᵻɡˈɑːɹdᵻd tədˈeɪ æz fˈɪzɪks, baɪˈɑːlədʒi ænd ˈʌðɚ nˈætʃɚɹəl sˈaɪənsᵻz.
In Aristotle's terminology, "natural philosophy" is a branch of philosophy examining the phenomena of the natural world, and includes fields that would be regarded today as physics, biology and other natural sciences.