Here's why it is highly improbably I would ever become a non-theist, why it seems the term is a negation not worthy for anyone to identify with, even those who do sincerely think the universe is purposeless.
#1 What counts in life is to define oneself by clear positive statements, not primarily by negative assertions of what one is not. The astrophysicist Neil deGrasse Tyson has a good example of this. In a lecture he explains why he doesn't call himself a non-theist:
“I don't play golf. Is there a word for non-golf players? Do non-golf players gather and strategize? Do non-skiers have a word and come together and talk about the fact that they don't ski. I don't--I can't do that. I can't gather around and talk about how much everybody in the room doesn't believe in God.” (http://www.haveabit.com/neil-degrasse-tyson/92001)
Such a good example of whimsical satire by Tyson! I used to play basketball every day, but eventually quit. Do I focus on the quitting, belong to ex-basketball.org;-)?
Seriously, while it is true, that there are life views and actions which are destructive that need to be opposed, we humans shouldn't define ourselves by our negatives—by not being or not doing.
Islam has slaughtered hundreds of thousands of innocent people in recent years, but do I strongly categorize myself, define who I am by saying, “I’m a Non-Muslim?” No.
So even though much of religion, theism, is delusionary and destructive why emphasize to others the negative, your whole identity as “not theist”?
Stand, instead, for what you are, for what is true.
#2 Speaking of “what is true…”: Ethics, aesthetics and seeking the ultimate meaning and purpose of existence is vastly important to me. In contrast, in the last 150 years nearly all of the non-theists, instead, have emphasized there are no standard ethics or universal aesthetics or object truth outside of the necessity (or chance) of natural selection, which they state is "without purpose or meaning."
According to biologist Richard Dawkins, altruism is likely a “misfiring of evolution.” (http://www.philosophicalinvestigations.co.uk/index.php/ethics/41-natural-law/452-extract-richard-dawkins-on-the-lust-to-be-nice?start=1)
In contrast, I’m intellectually convinced that ethics are as objective and real as math. Let’s say the human species is wiped out by a huge catastrophe. Would mathematics cease to be real in the cosmos? Would the natural regularities of nature such as gravity cease? No.
If there was an alien species on some distant planet on the far side of the Milky Way who was also conscious and rational and purposeful like humans, that species would have the same ethical standards—commitment to equality, honesty, fidelity, courage, compassion, justice, mercy, etc. and would oppose intolerance, persecution, rape, rapine, slaughter, and cruelty.
At least I sure hope so.
#3 Not only does such a view negate all universal ethics and aesthetics, many non-theists are so demeaning of what the human species is about.
For instance, the non-theist Sam Harris says human beings are “puppets,” that even each person’s sense of “I” is an illusion. He and two other non-theists commentators claim it’s “tumors all the way down,” meaning every human being has no more choice than a criminal who murders because a tumor is pressing down on his brain. (The Very Bad Wizards Interview #1: Episode 59 Tumors All the Way Down, samharris.org)
Other non-theists have characterized the human species as "bags of chemicals," "meat puppets," etc. Then there's Francis Crick's infamous description of the human species:
[Science has shown you that] "'you,' your joys and your sorrows, your memories and your ambitions, your sense of identity and free will, are in fact no more than the behaviour of a vast assembly of nerve cells and their associated molecules. as Lewis Carroll's Alice might have phrased it: 'You're nothing but a pack of neurons.'" (http://www.todayinsci.com/C/Crick_Francis/CrickFrancis-Quotations.htm)
Caution! This is not a denial that Harris’ (or Dawkins' or Crick's) hypotheses could be correct. I’m only pointing out that unless overwhelming evidence is found that humans are “puppets,” that our sense of “I” is an illusion, and that ethics are only evolutionary adaptions of a purposeless regularity in nature, then I will continue to hold the human species as valuable and creative and purposeful.
#4 Generally, nontheists are too sure there is no ultimate meaning to existence, adamantly sure. For this reason, Albert Einstein said he wasn't a non-theist.
He wrote, “I’m not an atheist…there are the fanatical atheists whose intolerance is the same as that of the religious fanatic, and it springs from the same source…They are creatures who can’t hear the music of the spheres.” (The Expanded Quotable Einstein, Princeton University Press, 200, p. 214)
#5 Furthermore, so many public nontheists are strident “in your face,” “know-it-all” arrogant, dismissive of anyone who disagrees with them, even rude, vulgar, and intolerant. Sounds pretty much like what non-theists accuse theists of being doesn't it?
(CAUTION: There’s no reason non-theists couldn't be more open and attentive. In fact, some fine non-theists are measured and considerate.)
In contrast, our goal in life could instead be-- to be courteous, tentative, open, tolerant, attentive, a good listener, decent, etc.
To sum up:
Theism (from Greek “theos” god) is “…the existence of one God viewed as the creative source of the human race and the world who transcends yet is immanent in the world.” (Merriam-Webster Dictionary)
Non-theism (from Latin “non” not) means “not” or “no” god.
That means in order for me to become a non-theist, I would have to agree there are no objective values (beyond,transcendent of the human brain and natural selection), no true universal ethics, no objective aesthetics, no ultimately real meaning and purpose for the cosmos. There would be no objective basis for equality and human rights, because there is no “equality” in the nature. Because in non-theism, of course, “human rights” are only a social construct, or worse are only an illusion/delusion caused by the determinism of the cosmos.
Since I am convinced by reason, experience, and emotion down to my inner marrow that equality, fidelity, honesty, and compassion are objectively true, and that slaughter and rape and torture and dishonesty are truly and universally wrong and that they cause untold suffering and pain and death, it would take a herculean change of my whole worldview for me to embrace the outlook that so many non-theists hold overtly.
Good and evil aren't relative.
Honesty or compassion are as real as 2+2=4 or the Theory of Gravity.
In the Light,