How do the themes/story of the old woman contribute to the overall message in Voltaire's Candide?

In 's
novel, , the three themes that stand out in the old woman's tale for me
are:

• one cannot depend that things will always stay the same:
  being rich and famous one day does not necessarily guarantee that this will not
  change
• even though we may believe our troubles are awful, there is always
  someone with difficulties worse than our own
• even when we hate our lives
  and think it would be better to be dead, we still hold on to life; while there is life, there is
  still hope

Voltaire wrote Candide in the
form of a  (a form of ) directed toward Gottfried Wilhelm von Leibnitz and his philosophy on
optimismwe see this in Pangloss' teachings and attitude which continually return to his belief
that in every situation, "this best of all possible worlds." In other words,
everything is as it should be.

My sense is that more than having an
unshakable belief that things are always for the best no matter the circumstances, I imagine
that Voltaire believed a realistic approach to life was more valuable. This is not to say that
people should not have an appreciation for positive things in their life, but one need not
appreciate difficulties and hardships, seeing them as positive parts of our
human existence.

Because Voltaire is making fun of optimism under every
circumstance, I believe the old woman's story, and the themes found there, encourage the reader
to feel positive when appropriate, and sad when a situation dictates it. Bad things happen, but
this is not something we must accept without resistance or feeling.

The ideas
that things can change at any time, there are always other people with problems worse than our
own, and regardless of our heartaches, life is still valuable are realistic concepts that follow
the advice that the old woman shares: she is not silly enough to believe that watching her
mother murdered was "the best of all possible worlds." And this is exactly what
Voltaire was trying to share with his audience. The author uses the character of the old woman
to allow us to feel honestly about the things that fill our life: thankful when things are good,
and hopeful when things go awry.