If it had not been so, all beings of the universe would have been alike, being the manifestation of the One and only Being. The difference of likeness among the races during different periods, and the difference of the features and natures among children of the same parents shows that the cause of all difference has been time and space. There is a greater resemblance between twin born children owing to their birth taking place so near together. Yet in this case the difference has the same cause. Germs, insects, birds, and beasts resemble each other much more closely than human beings, birds more so than beasts, and germs more so than insects, because so many of them are born at the same time.