After the process of degradation had begun, after the primitive type had given place to the bi-sexual human race, and a species was thus formed, further degradation would be inevitable under the same causes which produced the first one. The female part of mankind would go on bringing forth new males and new females, and to each one at birth there would come from its peculiar star an immortal soul, for I do not understand that Plato's women were supposed not to be constructed, in this respect, upon the same plan as the men. But each of these newly arrived immortal souls would be placed in a mortal body in contact and conflict with the two mortal souls of appetite, disturbance, and mutiny against the divine laws of reason. Each new human being would then be exposed to further debasement, by which his or her human organs and human form would undergo transformation into a lower type of animal life. Accordingly, we find that Plato, in perfect consistency with his theory, supposes that birds are a degraded birth or formation derived from one peculiar mode of degeneracy in man, hair being transmuted into feathers and wings. If we inquire from what kind of men the birds were formed, and how they came to be assigned to the air, we shall best learn from the words employed by Mr. Grote to express Plato's idea: "Birds were formed from the harmless but light, airy, and superficial men, who, though carrying their minds aloft to the study of cosmical phenomena, studied them by visual observation and not by reason, foolishly imagining that they had discovered the way of reaching truth."[18]