Let that which stood in front go behind, let that which was behind advance to the front, let bigots, fools, unclean persons, offer new propositions, let the old propositions be postponed.

Use a gyroscope to demonstrate how, over time, we become fixed in our ways, personalities, and, as a mature person, psychologically resistant to change. With EFFORT, however, we can make changes. We are not today exactly what we were yesterday. We are almost imperceptibly different. We do change with time and we can control to an extent the direction of the changes.

They must change who would be constant in happiness and wisdom.

That things are changed, and that nothing really perishes, and that the sum of matter remains exactly the same, is sufficiently certain.