Immortality

The Daoist seeks immortality.
Yet the Daoist does believe that all that exists is natural. He does not believe in the supernatural.
And the Daoist accepts the fact that death is a natural part of life.
So how come the Daoist seeks immortality?

The Daoist doesn’t pursue immortality believing it is attainable.
He strives for immortality knowing that he will never attain it.
He does so nonetheless, because through this striving he achieves the greatest longevity he could ever achieve.