There's an argument that says that without God, life has no meaning. Some of us actually embrace this as a great liberation. If life has no meaning we are free to imbue it with any meaning we wish. This, however, doesn't satisfy those whose faith demands meaning imposed from above. If you deny that life has intrinsic meaning, they say, and maintain that meaning imposed by God is a myth, inventing meaning in its place is surely equally mythical.
For me, this misunderstands the kind of thing that 'meaning' -- in this context -- is. Meaning in life is not, as some would have it, a kind of goal, or purpose, or ideal end target. To say that life has meaning does not necessarily imbue it with externally imposed direction or intention, and neither does inventing your own meaning. Life just is. What you do with it is your affair.
Meaning in life is not so much a property that it possesses, more a declaration of those who live it.
In a hypothetical conversation between three umpires about strikes in baseball, Umpire 1 says, "I call 'em as they are." Umpire 2 says, "I call 'em as I see 'em." Umpire 3 says "They ain't nothin' till I call 'em." This illustrates the difference between attempting to perceive something that's already there, and acknowledging that some properties don't actually exist at all. Umpire 3 is not claiming flawless perception of objective reality as Umpire 1 is, nor is he admitting imperfect perception of reality, as Umpire 2 is. Umpire 3 is saying that this particular reality doesn't exist until he says it does. That, after all, is his job.
(Incidentally I put some of this worldview speculation into my very first published short story, "The Journey of Jonathan Cave" -- initially published on line at Alien Q, subsequently read on my podcast The Rev Up Review, then re-recorded for publication in Mur Lafferty's audio anthology Voices: New Media Fiction, available for free at Podiobooks.com.)
The concept of 'meaning' in life is a bit like the concept of evolution. Saying 'survival of the fittest' is not to say that the overall grand purpose of evolution is to weed out those less fit. Evolution doesn't have a grand purpose. It just is. If it does tend to weed out those less fit to survive and reproduce in prevailing environmental conditions, this says nothing about whether it's a good or bad thing. Morality doesn't come into it. It's simply the way the mechanism of evolution works.
Your life has no meaning until you say it does. That's your job.