Aristotle implies that in a vacuum the speed of fall would become infinite, and concludes from this apparent absurdity that a vacuum is not possible.
ˈæɹɪstˌɑːɾəl ɪmplˈaɪz ðæt ɪn ɐ vˈækjuːm ðə spˈiːd ʌv fˈɔːl wʊd bɪkˌʌm ˈɪnfɪnət, ænd kəŋklˈuːdz fɹʌm ðɪs ɐpˈæɹənt ɐbsˈɜːdᵻɾi ðˌæɾə vˈækjuːm ɪz nˌɑːt pˈɑːsᵻbəl.