For some natures, changing their opinions is just as much a requirement of cleanliness as changing their clothes: for others, however, it is merely a requirement of vanity.
The alchemists spent years in their laboratories, observing the fire that purified the metals. They spent so much time close to the fire that gradually they gave up the vanities of the world. They discovered that the purification of the metals had led to a purification of themselves.
The most vulnerable and yet most unconquerable of things is human vanity; nay, through being wounded its strength increases and can grow to giant proportions.
For it is a matter of daily observation that people take the greatest pleasure in that which satisfies their vanity; and vanity cannot be satisfied without comparison with others.
The strongest knowledge (that of the total freedom of the human will) is nonetheless the poorest in successes: for it always has the strongest opponent, human vanity.
Some have lavish garments, carry sharp swords, and feast on food and drink. They possess more than they can spend. This is called the vanity of robbers. It is certainly not the Way.