"The time of a man's life is as a point; the substance of it ..." — Marcus Aurelius quote meaning

The time of a man's life is as a point; the substance of it ever flowing, the sense obscure; and the whole composition of the body tending to corruption. His soul is restless, fortune uncertain, and fame doubtful; to be brief, as a stream so are all things belonging to the body; as a dream, or as a smoke, so are all that belong unto the soul. Our life is a warfare, and a mere pilgrimage. Fame after life is no better than oblivion. What is it then that will adhere and follow? Only one thing, philosophy. And philosophy doth consist in this, for a man to preserve that spirit which is within him, from all manner of contumelies and injuries, and above all pains or pleasures; never to do anything either rashly, or feignedly, or hypocritically: only to depend from himself, and his own proper actions: all things that happen unto him to embrace contentendly, as coming from Him from whom he himself also came; and above all things, with all meekness and a calm cheerfulness, to expect death, as being nothing else but the resolution of those elements, of which every creature is composed. And if the elements themselves suffer nothing by their perpetual conversion of one into another, that dissolution, and alteration, which is so common unto all, why should it be feared by any? Is not this according to nature? But nothing that is according to nature can be evil.