"If you draw a giraffe, you must draw him with a long neck. If, in your bold creative way, you hold yourself free to draw a giraffe with a short neck, you will really find that you are not free to draw a giraffe. ... You can free things from alien or accidental laws, but not from the laws of their own nature." G.K.Chesterton in Orthodoxy.
That man has a soul is generally accepted by most common folk - even writers and artists - though we may quibble over exactly what this soulishness means. For this article I would like to set forth a definition that most would accept - a throbbing ache for fulfillment. We seem to be born with a longing for meaning and significance. Most of us eventually discover that meaning and significance are not found in the physical pleasures or acquisitions of life. In the words of Ravi Zacharias, "The loneliest moment in life is when you have just experienced what you thought would deliver the ultimate, and it has let you down." (from Can Man Live Without God)
But where do we look to satisfy this soulishness? That's the issue.
The Christian view is that the soul is a God implanted compass to draw us outside of ourselves pointing us to look to something higher and greater. That's all I will say about this view because I want to focus on several atheistic/humanistic approaches.
The first view I call the honest view. I will use famous 20th century atheist Bertrand Russell as it's proponent. His remark that life must be lived in a state of "unyielding despair" both states that there is no higher purpose or meaning to look to and correctly analyzes the life result of that belief - despair, with no hope and no way out. In short, Russell says there is a yearning but no ultimate fulfillment for life. There is no meaning.
"We are here because one odd group of fishes had a peculiar fin anatomy that could transform into legs for terrestrial creatures; because comets struck the earth and wiped out dinosaurs, thereby giving mammals a chance not otherwise available (so thank your lucky stars in a literal sense); because the earth never froze entirely during an ice age; because a small and tenuous species, arising in Africa a quarter of a million years ago, has managed, so far, to survive by hook and by crook."We may yearn for a 'higher' answer—but none exists. This explanation, though superficially troubling, if not terrifying, is ultimately liberating and exhilarating" Stephen Jay Gould
The second I call get over it. A proponent of this view was the late Stephen Jay Gould. As shown above, his view says man can be liberated and exhilarated (his notion of the soul's fulfillment) if we just face the facts squarely and get on with it. Interestingly enough, though, his language gives him away - "This explanation, though superficially troubling, if not terrifying, is ultimately liberating and exhilarating." If man is just a cosmic accident, why should there be anything to trouble or terrify? Man's soulishness becomes a cosmic joke played by blind chance.
"The feeling of awed wonder that science can give us is one of the highest experiences of which the human psyche is capable. It is a deep aesthetic passion to rank with the finest that music and poetry can deliver. It is truly one of the things that make life worth living and it does so, if anything, more effectively if it convinces us that the time we have for living is quite finite." Richard Dawkins, Unweaving the Rainbow: Science, Delusion and the Appetite for Wonder
Richard Dawkins is an example of the third view which I call counterfeit. Dawkins seems to agree that the things that give meaning to life are not the physical but the ethereal experiences of awe and wonder from science, music, poetry, etc. From his evolutionary/atheistic perspective, however, Dawkins is amazed at what the mind of man can conceive rather than that man's mind can conceive at all. It's like those who look at the amazing pictures from the Hubble space telescope and only marvel at man's accomplishment of building and placing such a great and powerful instrument.
Conclusion. Yes, it is fearful to contemplate the vastness of empty space teaming with billions and billions of stars. How small and insignificant this makes man -- if the measure is man alone. No further can the atheist/humanist go. Left with the honest assessment of unyielding despair, or the get over it bravado of the superficially troubling, if not terrifying truth of accidental and meaningless existence, or the counterfeit of looking low to the creature for awe and wonder, these all draw a giraffe with a short neck - man with a much diminished soul - in short, inviting man to suicide.
"Do not free a camel of the burden of his hump; you may be freeing him from being a camel. Do not go about as a demagogue, encouraging triangles to break out of the prison of their three sides. If a triangle breaks out of its three sides, its life comes to a lamentable end." G.K. Chesterton