.....Bahá'u'lláh has announced that no
matter how far the world of humanity
may advance in material civilization,
it is nevertheless in need of spiritual
virtues and the bounties of God. The
spirit of man is not illumined and
quickened through material sources.
It is not resuscitated by investigating
phenomena of the world of matter. The
spirit of man is in need of the protection
of the Holy Spirit. Just as he advances
by progressive stages from the mere
physical world of being into the intellectual
realm, so must he develop upward in
moral attributes and spiritual graces.....

           ~ Abdu'l-Baha
                The Promulgation of Universal Peace
                p. 288