The studies of philosophy, therefore, and philosophy itself, are aids in treating of the truth. For instance, the cloak was once a fleece; then it was shorn, and became warp and woof; and then it was woven. Accordingly the soul must be prepared and variously exercised, if it would become in the highest degree good. For there is the scientific and the practical element in truth; and the latter flows from the speculative; and there is need of great practice, and exercise, and experience.