This is an illustration of a penguin or a rabbit. It depends upon how you choose to perceive it. Both animals are synthesized into one.
It is the same with us. We are both Optimists and Pessimists. The difference between the Optimist and the Pessimist is that the Optimist thinks that “This is the Best of all Possible worlds,” the odd thing is that the Pessimist agrees.
They are back to back facing in opposite directions, where the Pessimist is facing away from the Light and sees nothing but shadow, the Optimist is facing the Light and sees No shadow. If the Pessimists wish to become optimists then all that is required is to change the direction of their view.
I feel that this is borne out by the demonstrable fact that while it is possible to bring Light into a dark place and make it Bright, it is impossible to bring Dark into a Lighted place and make it totally Dark.
We choose to face the Light or face the Shadow. We are both the Light and the Dark.