Human beings are “the highest specialized organism of visible creation”

If we look with a perceiving eye upon the world of creation, we find that all existing things may be classified as follows: first, mineral -- that is to say, matter or substance appearing in various forms of composition; second, vegetable -- possessing the virtues of the mineral plus the power of augmentation or growth, indicating a degree higher and more specialized than the mineral; third, animal -- possessing the attributes of the mineral and vegetable plus the power of sense perception; fourth, human -- the highest specialized organism of visible creation, embodying the qualities of the mineral, vegetable and animal plus an ideal endowment absolutely absent in the lower kingdoms -- the power of intellectual investigation into the mysteries of outer phenomena. The outcome of this intellectual endowment is science, which is especially characteristic of man. (‘Abdu’l-Baha, The Promulgation of Universal Peace, p. 29)