Step-by-step explanation:
We can infer the meaning of this quote by considering the context of the statement. For example, a few lines before this quote, we are told by Alexis de Tocqueville,
"He who has set his heart exclusively on the pursuit of worldly welfare is always in a hurry, for he has but a limited time at his disposal to reach, to grasp, and to enjoy it."
Hence, what the quote means is that man (i.e Gatsby), has an insatiable desire to enjoy what life can offer with the fear of dying in mind; despite the good things he already has.