The truth value of this assumption—which underlies Euclidean geometry and serves as a useful model in everyday measurement—is a matter of philosophical speculation, and may or may not reflect the changing realities of "space" and "distance" on the atomic level (approximately the scale of a nanometer).
ðə tɹˈuːθ vˈæljuː ʌv ðɪs ɐsˈʌmpʃən—wˌɪtʃ ˌʌndɚlˈaɪz juːklˈɪdiːən dʒiˈɑːmətɹi ænd sˈɜːvz æz ɐ jˈuːsfəl mˈɑːdəl ɪn ˈɛvɹɪdˌeɪ mˈɛʒɚmənt—ɪz ɐ mˈæɾɚɹ ʌv fˌɪləsˈɑːfɪkəl spˌɛkjʊlˈeɪʃən, ænd mˈeɪ ɔːɹ mˈeɪ nˌɑːt ɹᵻflˈɛkt ðə tʃˈeɪndʒɪŋ ɹɪˈælᵻɾiz ʌv "spˈeɪs" ænd "dˈɪstəns" ɔnðɪ ɐtˈɑːmɪk lˈɛvəl ɐpɹˈɑːksɪmətli ðə skˈeɪl əvə nˌænoʊmˈiːɾɚ.