I formulate my research question as "Is the claim of naturalists justified that the discussion of the "possibility of meaningful life" is dependent on scientific achievements, especially modern physics?". In this regard, two concepts are distinguished from each other: one is "the meaning of the life of Humans (homo sapiens)" in the universe (in short, "the meaning of life") and the other is "meaning in the life of any specific human" (in short, "meaning in life"). Then, based on the two mentioned concepts, the two corresponding challenges, which the naturalists have raised for the purposefulness of the world and the meaning of human life, are described and investigated: the first issue is related to the findings and models of modern cosmology regarding the history and destiny of the universe, and the second issue is related to the determinism/indeterminism controversy in physics, especially quantum mechanics. In this article, the claim of naturalists to deny the possiility of meaning of life (the first concept) is examined and criticized in detail, then it is shown that, contrary to the claim of naturalists, the defense of the possibility of meaning in life (the second concept) in no way requires the indeterministic interpretation of quantum mechanics and its extension to the macroscopic world. While criticizing and rejecting negative approaches to the issue of meaning in life in the deterministic world, positive approaches in this regard are described and examined.