An atheist assigns himself to life without ultimate purpose. I won't try to answer as if I represented all atheist on the world. That would be an error, we are diverse to the extreme. On my case, I'm Bright, but there are several guys out there who have no trouble in believing in karma or other things. If you use "ultimate" in the sense beyond my mere criteria. You are right, I don't believe in an ultimate purpose per se. I'm as anybody are born free. I choose my purpose. Based on my criteria. Does it work as well as your "ultimate" purpose? I have to assume I have some benefits of choosing what to do with my life, versus discovering what other people believe is best for me. Yes, I will make mistakes and I might redefine what I want of life. I would choose being responsible of my destiny anytime above being told what to think or do. (And remember believers also do this all the time, just they say they understand better their religion. I understand better the world.) Please let's be succint. Some put responsibility on themselves, some don't. I choose the first.
On the feeling that there must be something more to existence. Could you please give anything that supports your idea? For you might be common sense. For me, it doesn't. You see, universe is a great enticing place to exist, so I don't dream of living in another one. I love to discover it. If I'm suppressing a feeling, could you please show me a study of how mankind is hardwired to desire something more beyond what exist? How can you really desire that if you don't even know all that exists?? Your common sense isn't a proof of anything, common sense is just the knowledge of what your subjective experience has told you it works to believe in that.
The atheist must also suppress the demands of logic. That's a harsh assertion. It's really an argument in pro of ID. Sorry, evolution is enough to understand how complexity arises. Though I would be really interested in listening how you believe that such a complex god could arise ex nihilo, while an encyclopedia, a simple thing compared with deities is such a problem.
Yet, ironically, the atheist has to believe in miracles without believing in God. First mobile argument. I love it. Unfortunately there's a concept that I've discovered is really hard for many to understand, chance. And this isn't just for Christians, it's for almost anybody. It's against our common sense. Our brain is hardwired to detect patterns. Please see a cloud and tell me what you see. Anyway, not every phenomena has a cause. Period. We are used to that, but there's nothing in logic that tell us that everything has to have a cause. It's like asking, where does a circle starts? Or with numbers, we know 2 is the first prime, what is before that one?? It just don't follow that way.
An atheist must also suppress all notions of morality. Uhm? Are you proclaiming that just because I understand how morality comes to be, I won't fine pleasure to call myself a honest man? I'm not above morality, just because I like it. I understand it and use it. It's a good tool. I willingly prevent myself from many things. Yeah, that sound completely immoral. Yes, I could rob and know that property is a constructed social norm. So what? I won't do it, because I care for society, for my people, for me. Again, believers also are able to do bad things, so once again it seems we are in mostly the same situation, not one of them being more moral. So, which one would you prefer to trust? A man whose morality comes from within, a careful realization of what world they want to be part, of a man whose ideas come from an outside construct? I choose the man who wants to be true to himself, ie the first.
In fact, the atheist must conclude that evil is an illusion. Yes, evil is an illusion. So what? That doesn't make me tolerate every attitude towards the world. Again it doesn't follow that I'll perceive murders as just people with bad manners. Though it might help me to understand a bit more his/her mind. What a shock. Maybe to you it's okay to stress how alien that mind must be. How impossible to you it is to commit such atrocious act. To me, it's not enough, have you heard about compassion? Why does this guy/girl murders? I must be really immoral to try to discern humanity in every person.
The atheist must also live with the arrogance of his position. I could say that many have touch this point before, but here I go. We can't prove the inexistence of anything. Ranging from pink invisible unicorns to whatever comes to your mind. Yet, we can assert that with the knowledge we have, up to this point, it's extremely implausible it's existence. So to be pragmatic, I'll act under the premise that there isn't one or many of these. I'm only convinced to the extreme that your idea of God is vague, so it is useless to me. And you are right, it is hard to be seen in good light when you oppose a belief so many have. I'm one of many who believe we shouldn't tolerate any idea, just because someone can have it. Each idea should be judged under their merits and vices. Please notice my remark that each idea has to pass a criteria. Let no one be fool, I'm against blind believing.
The atheist must also deny the validity of historical proof. Sorry, which proof? I'm really interested on any proof of Jesus' historicity. Could you point me to a roman slaughter of infants? A belem star? Anything besides the bible, I hope you can understand I don't believe in a biased book. The good news is that Romans and Jews where great in keeping records, so it shouldn't be such a problem. If in the mean time you found proofs of a great flood, ten plagues, a day in history where the sun stayed more than a day, or any of those miracles, let me know.
Finally, the atheist must admit that human beings are not importantly different from other animals. True. I'm sorry that you find repulsive the idea that every living being in this world is linked by a family tree. Have to correct you, evolution isn't just a random process. It's an algorithm. So successful that we sometimes copy it. It can err, but in general it is enough for life to survive. BTW, because it sometimes gets stuck in local maximums, that's why we know we aren't designed by an all-known engineer. I would tell you that you should look more closely to other animals, maybe you'll find a pleasant surprise. That animals understand camaraderie, self sacrifice for the benefit of others, among other things.
Always remember that the atheist's problem with belief in God is not the absence of evidence but the suppression of it. Can't discuss with you the last point. To put it bluntly, it's just what your book says and years ago I discovered that an appeal to authority is a plain fallacy. To my knowledge every child born needs to de indoctrinate to "understand" your god idea. That sounds totally opposite to your texts.
And that's it. If someone has a comment, let me hear about it.