We are evolving along two lines, the mental and moral, and a little consideration of the matter will make clear two important points--that we have much to learn and that the physical plane is wonderfully arranged for our instruction. We have conditions here for developing mentality that do not exist on higher planes. The absolute necessity of procuring food is an example. Death is the penalty for failure to obtain it. Hunger was the earliest spur to action at the lowest level of evolution and even now at our high point of attainment it is one of the chief factors of racial activity. In providing the necessities of life and in gratifying our multitude of desires mentality is developed. Business and professional life rests upon these physical plane necessities and, engaged in solving the problems of civilization, the race evolves intellect. Such problems do not, of course, exist on higher planes. While the mentality is thus being pushed along in evolution by our material necessities, the heart qualities are developed by the family ties in a way that could not be done elsewhere. In the nature of things the entrance of the soul to the physical plane is attended with helplessness. From the beginning it must have material necessities or die, and yet it can do nothing in its new infant body. Again, as a rule, long before it leaves the physical plane old age has once more rendered it helpless. Thus every human being must depend on the assistance of others at two critical periods of each incarnation. The help it receives, in infancy and old age, it pays back to the race, in the care of both the helpless young and the helpless old, when it is in the vigor of mature physical life. It is obvious that such experience develops the qualities of sympathy and compassion as no phase of business life could. The relationship of parent and child, husband and wife, evolves the heart qualities in a way that would be impossible in the totally different environment of higher planes. Naturally enough, each plane has a specific work to do in the soul's evolution. We can no more learn in the highest planes the lessons the material world is designed to teach us than a pupil can acquire a knowledge of mathematics from his lessons in geography. Hence the necessity for a periodical return to this life until its experiences have developed in us the qualities we lack. Not only has each plane its special adaptability to particular needs of the soul in its evolution, but the two kinds of physical bodies--masculine and feminine--through which the soul functions, afford special advantages for acquiring the lessons of life. The soul on its home plane is, of course, sexless. Sex, as we know it, is a differentiation arising from the soul's expression on lower planes. All characteristics of the soul itself, like intelligence, love, or devotion, are common to both sexes.