Fourth is the issue of ultimacy, where God as envisioned by the theologian admittedly fits nicely. However, should there be no God; the universe, life, perhaps even humanity, may serve as ultimate, not to mention immaterial concepts such as Being, beauty, creativity, or science. Moreover these possibilities are immanent while the divine is elusive and intangible. Meaning seems more secure when one’s ultimate concern is readily apparent rather than hidden or questionable.
On the other hand, theology-based expressions of the meaningful life are easily countered by secular versions of them or by adoption by the agnostic or atheist. Tolstoy may be correct that meaning for him was belonging to a community of persons with simple faith in the Christian God, but the same is likely true for a community of humanists such as the one created by Epicurus in Athens. Thomas A. Kempis may find powerful worth in imitating the life of Christ, but we would expect this with imitating the life of many great individuals. Centuries before Christ, Democritus said “One should be or imitate a great man.”
We have already seen in this site’s section called Suffering that human suffering does not negate human meaning.. In particular Viktor Frankl having suffered immensely in a concentration camp found being worthy of one’s suffering can instantiate meaning in one’s life. With all due respect to Paul Tillich, it seems to me self-transcendence and the conquest of finitude and ambiguity is possible without religious symbols; in fact, the concept of Being seems more tangible to me than Christian religious symbols, and his powerful presentation in The Courage to Be can be embraced without adding a deity beyond Being itself. Last Unamuno might himself admit, that acting so as to merit eternity and the approval of the divine is not contingent on there being a divine being at all.
Two final points- first the opacity of God’s will, purpose, and expectation of humans assures us we can never be certain we have achieved a divinely-approved meaningful life. Second, formal religions take this even farther; their truth by authority will always be suspect, inevitably leading to a personal internal conflict of reason and dogma. A salient example is the Holy War, the killing of innocent non-believers at the urging of ecclesiastics in the name of God.
In summary there are reasonable counter-arguments to the necessity of God in the struggle to find meaning. Belief in God may affect how one chooses to find meaning and the role one plays, but it may well turn out that the meaningful life is more tenuous for believers. Now we must confront the opposite issue, that of nihilism – that there is and can be no meaning of life.