The logical outworkings of atheism lead to a belief system that he [Dawkins] is unable to live by. Its radical materialism destroys the notions of right, wrong and justice- indeed the reality of any concept or idea relating to values and standards...Standards of good and evil are not material - they are something beyond the natural, physical world and therefore, if Dawkins is right, they cannot exist. When Dawkins says that theism is a force for evil he is denying his own assertion about the fundamental nature of existence. (Reading on a Kindle so I cannot give a specific page but this is from the last few paragraphs of Chapter two.)
Barns is clear, but wrong. Notions and standards of good, evil and justice are immaterial but that does not mean they do not exist or are without value. Imaginary numbers are immaterial but have great value in math. Good and evil are tougher to explain, but justice is inherently about math, measurements and balance. There are plenty of philosophical frameworks that attempt to rationalize and codify the concepts of good and evil, usually involving easy-to-understand but hard-to-actually-use criteria like 'acts that maximize happiness' or 'acts that deliberately inflict suffering'.
This is dodging Barn's point and the point of this essay. Measurable or not, material or not, can our instinctive understanding of good and evil come from a source other than God?
Yes, they can.
Let me give two explanations, one somewhat more theoretical and the other more currently practical, although still under investigation. The two can be seen as 'Distant Past' and 'Modern Example predicted by Distant Past' or as independent of one another.
First, explanations for altruistic behavior come from Dawkins' own The Selfish Gene (Wikipedia) and from Game Theory. From the Wikipedia article on The Selfish Gene:
"In describing genes as being "selfish", the author does not intend (as he states unequivocally) to imply that they are driven by any motives or will, but merely that their effects can be accurately described as if they were. The contention is that the genes that get passed on are the ones whose consequences serve their own implicit interests (to continue being replicated), not necessarily those of the organism, much less any larger level.
This view explains altruism at the individual level in nature, especially in kinship relationships: when an individual sacrifices its own life to protect the lives of kin, it is acting in the interest of its own genes. Some people find this metaphor entirely clear, while others find it confusing, misleading or simply redundant to ascribe mental attributes to something that is mindless. For example, Andrew Brown has written:
"Selfish", when applied to genes, doesn't mean "selfish" at all. It means, instead, an extremely important quality for which there is no good word in the English language: "the quality of being copied by a Darwinian selection process." This is a complicated mouthful. There ought to be a better, shorter word—but "selfish" isn't it."
My own, imperfect, understanding of altruism in The Selfish Gene is that any behavior that increases the number of copies of my DNA is going to be promoted. So who has my DNA? My son has the most, but so do my nieces and nephews, and my cousins and their children... in increasing numbers but decreasing percentages. I am not sure if this means I should accept some tiny loss for helping anyone with some of my characteristics? If I help brown-eyed, left-handed, lazy people, am I in some way promoting my own DNA? I am not sure if evolutionary explanations can be stretched quite that far.
The mathematical modelling of Game Theory can be.
A short, non-technical explanation of Game theory:
Much of evolution and natural selection can be summarized in three short words: “Life is games.” In any game, the object is to win—be that defined as leaving the most genes in the next generation, getting the best grade on a midterm, or successfully inculcating critical thinking into your students. An entire field of study, Game Theory, is devoted to mathematically describing the games that nature plays. Games can determine why ant colonies do what they do, how viruses evolve to exploit hosts, or how human societies organize and function.
In the end, the students learned what social insects like ants and termites have known for hundreds of millions of years. To win at some games, cooperation is better than competition. Unity that arises through a diversity of opinion is stronger than any solitary competitor.
Morally, of course, games can be tricky. Theory predicts that outcomes are often not to the betterment of the group or society. Nevertheless, this case had an interesting result. When the students got carte blanche to set the rules, altruism and cooperation won the day. How unlike a “normal” test where all students are solitary competitors, and teachers guard against any cheating! What my class showed was a very “human” trait: the ability to align what is “good for me” with what is “good for all” within the evolutionary games of our choosing.
A popular account of another study:
Although this is obviously a very simple mathematical model and reality will never be as linear, Santos, Santos and Pacheco’s results gives us a total new perspective on how to look at ways of increasing cooperation/altruism and, consequently, also on how to create more successful societies, concerning issues as crucial to our survival as the protection of the environment or fairer social relationships, contributing in this way to the construction of a more peaceful world with less conflict and destruction.
As I understand the results, there are many situations where the winning strategy for a game could be egoistical behavior, but this is not always the case so any blanket statement that acceptance of evolution should mean selfish behavior is wrong.
As a side note, many of the games requiring selfless behavior to get ahead have multiple rounds. People can see and recall what happened before and react to the justice or injustice of the game. Apes show a similar understanding of justice.
How would this work? What mechanism would be used to model fairness and justice? Mirror neurons.
A mirror neuron is a neuron that fires both when an animal acts and when the animal observes the same action performed by another. Thus, the neuron "mirrors" the behavior of the other, as though the observer were itself acting. Such neurons have been directly observed in primate and other species includingbirds. In humans, brain activity consistent with that of mirror neurons has been found in the premotor cortex, the supplementary motor area, the primary somatosensory cortex and the inferior parietal cortex.These neurons assist us in feeling what others feel, in having empathy. Empathy then is not (merely or exclusively) immaterial; it has solid, material roots in specific parts of the brain.
I do need to be careful. These neurons can be used by hunters to understand prey activity or to model the activities of enemies to better fight them. There is nothing inherently 'good' about them or their evolutionary origins. Still, tools can start with one purpose and be used for others.
More from Wikipedia:
Stephanie Preston and Frans de Waal, Jean Decety, and Vittorio Gallese and Christian Keysers have independently argued that the mirror neuron system is involved in empathy. A large number of experiments using fMRI, electroencephalography (EEG) and magnetoencephalography (MEG) have shown that certain brain regions (in particular the anterior insula, anterior cingulate cortex, and inferior frontal cortex) are active when people experience an emotion (disgust, happiness, pain, etc.) and when they see another person experiencing an emotion. However, these brain regions are not quite the same as the ones which mirror hand actions, and mirror neurons for emotional states or empathy have not yet been described in monkeys.
More recently, Christian Keysers at the Social Brain Lab and colleagues have shown that people who are more empathic according to self-report questionnaires have stronger activations both in the mirror system for hand actions and the mirror system for emotions, providing more direct support for the idea that the mirror system is linked to empathy. Some researchers observed that the human mirror system does not passively respond to the observation of actions but is influenced by the mindset of the observer.  Researchers observed the link of the mirror neurons during empathetic engagement in patient care .
The other important thing I want to say is that mirror neurons are obviously the starting point for things like empathy, but that’s all it is—I mean, you need much more. If mirror neurons are involved in things like empathy and language and all of that, then monkeys should be very good at these things. One of the things I argue, and others have argued, is that mirror neurons are important in transmitting skills from generation to generation. I need to put myself in your shoes to observe what you’re doing, and to mime it accurately. Mirror neurons are important in that.
Evolution has lead to many successful strategies and many of these are horrific, from the dumping of huge numbers of young in the hope that some will survive as salmon do to the killing of a competitor's offspring to encourage their mothers to mate as lions do. Still, some of these strategies appear more moral, more 'good'.
I am not sure that the behaviors of bees or ants fit this description. Individuals of both groups will die to protect their colonies but do so with so little free-will that the result is nearly as abhorrent as more selfish behavior would be. Still, other social animals often do show admirable behaviors. Gulls and prairie dogs give alarm calls to warn neighbours of approaching danger (and even here is another trait recognizable in humans: some fraudulently give the alarm call to scare neighbours away from valuable food).
Acceptance of evolution is not the same as atheism so I could have avoided the whole argument by reminding readers that many evolution proponents are also Christians. Still, the groups, atheists and evolution proponents, are closely linked.