Most atheists I know are caught in a Kantian paradox. They want to say they "know" what naturalistic science reports to be objectively true (that only the material world is real), but they want to live AS IF they believe in the objective reality of the immaterial world which contains laws of morality and thought, meaning, the mind, human will, human consciousness, human dignity, justice, beauty, rights, etc. Yet, as a consistent thinker, they must admit that these abstract entities are only illusions. So, they live in tension. But it is worse than that. Kant admitted that these two realms appear to contradict each other. If the unguided machine of scientific materialism governs and perfectly determines every event in the universe, then it governs every event in the human body. There is no meaning behind the term "self" or "I" because humans are only cogs in an impersonal deterministic machine. We are, as one Darwinian thinker has put it, "complex computers made of meat." Every thing that we do and everything that happens in the world is determined by the laws of physics, including all of those immaterial concepts which give life meaning, joy, and ethical significance. In the Middle Ages, the immaterial conceptual world (call it the upper story) was given priority. But Enlightenment thinkers, especially David Hume, argued that the material world was all that exists and that the immaterial world was simply a part or product of the material world. So, he became a skeptic. We can't know anything beyond our sense experience truly (he even started to question whether we could know the material world as we experience it truly).
Basically, the early Enlightenment thinkers like Hume argued that all knowledge is reducible to scientific materialism (the lower story). Religion, morality, art, beauty, and so on, since they can't be investigated scientifically, were considered irrelevant spin-offs of a naturalistic deterministic machine. The Romantics responded by trying to reassert the value of these things with their philosophy of idealism (ultimate reality is not material but spiritual or mental). The Romantics were willing to concede that mechanistic science deals in material world but that the arts and humanities are important as they deal in the equally important immaterial world. Kant comes along and tries to bring philosophical harmony. Kant wanted to affirm the existence of what he found to be two contradictory realities. He said that humans are free and autonomous in life as they consider immaterial concepts of morality, beauty, justice, etc. But he said, of course, that we really know that all these ideas are ultimately meticulously determined by the laws of the materialistic machine. That is, in the upper story he put freedom (the autonomous self of free man with the ideas of justice, morality, the good, etc.). In the lower story he put nature (or the Newtonian World Machine). Like the Romantic Rousseau, he wanted to say that man as a free creature or "self" capable of assigning meaning and morality to his behavior and identity, actually exists and is not part of the Newtonian deterministic machine (if he was, life really would be as meaningless and morality as illusory as Hume suggested). But Kant fails to avoid self-contradiction, as even he acknowledged. As Nancy Pearcy put it (taken from her book Total Truth), "in the lower story he was talking about things that actually exist, the constituents of the real world -- while in the upper story he was talking about a realm of concepts or principles that we assume only because they are necessary for morality [and meaning and happiness]. Since morality requires freedom of the will [an uncoerced will], we must suppose ourselves to be free, no matter what science says to the contrary. Since, the correspondence of happiness with virtue cannot be left to mere coincidence, we must suppose there is a God who guarantees it. And since moral perfection cannot be attained in this life, we must suppose ourselves to live forever...In short, the lower story is what we know; the upper story is what we can't help believing" in order to make sense of our every day experience. Kant actually said that regardless of what naturalistic science says, we must act "AS IF" we were free, moral, valuable, significant, meaningful, etc. We must act AS IF there are transcendental laws of morality, thought, and so on because they are the necessary preconditions of intelligibility. We must trick ourselve. Basically, Kant was saying that in order to function in this life, we must live in paradox or irrationalism (hence Francis Scaeffer’s book titled Escape From Reason). That is, as Pearcy explains Kant, "we operate within a physical world completely determined by natural laws (lower story); and at the same time, we participate in a conceptual world where we conceive of ourselves as free moral agents (upper story)." The material world is all that that the atheist confirms, but he won’t (can’t) live that way. He must presuppose the immaterial world in order to function.
Of course, then Darwin comes along and offers the first plausible naturalistic mechanism for the origin of life, and so there goes God (the concession of deism that enlightenment thinkers typically made). As Dawkins has said, "Darwin made it possible to be an intellectually fulfilled atheist." The lower story, to more and more naturalistic thinkers, was not real but an illusion or convenience. We invent those abstract entities and treat them as absolute so that we do not go crazy or drive ourselves to despair or whatever. Steven Pinker, an MIT scientist, has said that "Ethical theory requires idealizations like free, sentient, rational, equivalent agents whose behavior is uncaused [by the determinism of scientific materialism]," and yet "the world, as seen by scien[tific naturalism], does not really have uncaused events." That is, ethics depends on the reality of something that materialistic science has declared to be unreal. This is the so-called Kantian and secular "leap of faith" which describes western thought from Kant until today. Pinker admits that irrationalism is the only option. "A human being is simultaneously a machine and a sentient free agent, depending on the purposes of the discussions." Pinker must conduct his life AS IF scientific materialism is untrue. In his personal life, he is forced to affirm the reality of things the existence of which his worldview denies. He must take a "leap of faith" in order to make life intelligible and meaningful. He even calls this mysticism (ironically given the common use of that word by atheists to describe the thought of theists). Pearcy says of his dilemma and so many others who are finally made aware of this paradox (including you the reader now), "Either you can try to be consistent with evolutionary naturalism in the lower story -- in which case you have to deny the existence of consciousness and free will [and meaning, transcendental laws of thought and morality, etc.]. Or else you can affirm their existence though they have no basis within your intellectual system -- which is sheer mysticism. An irrational leap." An Escape from Reason. That is, they are practicing theists but creedal atheists. Pearcy: "Adherents of scientific naturalism freely acknowledge that in ordinary life they have to switch to a different paradigm. That ought to tell them something. After all, the purpose of a worldview is to explain the world -- and if it fails to explain some part of the world, then there's something wrong with that worldview." One may say that they are no more than a machine, but as Schaeffer says, "his whole life denies it." That is, the atheist must walk by faith. In reality, however, he is only borrowing from Christianity in order to function. Of course, though there is no ground for one's conviction of their own freedom, a compelling personal and social moral conscious, and so on in scientific materialism, there is in Christianity. God made man in His likeness and transmits knowledge to His mind so that he is really capable of knowing truly and objectively both the material and immaterial world. The non-Christian, unable to make sense of the world and unable to make life intelligible apart from Christianity, uses Christian categories, concepts, and principles in order function in life and even to make their case against Christianity. To put it a bit more bluntly, they slap the hand that feeds them.
Finally, as Francis Schaeffer predicted, the lower story tends to "eat up" the upper story. Earlier in this post I pointed out that people tend to behave AS IF the immaterial world exists. But as they become more and more consistent with the worldview of philosophical naturalism and scientific materialism, they tend to acknowledge or recognize or admit that the upper story is unreal. That is, it too is a product of the materialistic determinism in the lower story and so there really is no authentic upper story. It's all an illusion. For many, this realization leads to despair, self-indulgence, acceptance of immorality, injustice, violence, etc. I once watched someone go through this process. When he fully understood what consistency in his worldview required, he became accepting of and even favored the infanticide, involuntary euthanasia, involuntary sterlization of those deemed “unfit.” Another person I knew came to believe that man is no more valuable than ants or birds. Peter Singer, the famous Darwinian Bioethicist at Princeton, has said the same thing. He has also, incidentally, argued that some animals are more valuable ("ethically significant") than some humans. Some simply admit that, though they would not do it, they can't hold moral objections to those things because nature is only running its course. When others come to this realization, like Marquis De Sade did, they loose all self-control and indulge themselves in that which pleases their senses (torture of women in his case). Others, after having realized that they are merely cogs in a materialist machine, lose any sense of meaning and purpose and turn to suicide (this was Francis Schaeffer's target ministry group). Others deal with this reality in other ways (alcohol and drugs). Fortunately, by God’s grace, countless others do not choose to escape from reason, but choose to escape to reason by finding the only worldview that provides them with a system of thought that is coherent and consistent, that makes sense of the world as it is experienced, and contains the possibility of knowing the seen and unseen truly and objectively.
I recently had a conversation with an atheist about this. After reviewing several of our discussions, I showed him that he was caught in the Kantian paradox using his own words. How?
1. Laws of Morality. He said: "the idea of ‘absolute morals’ is a meaningless idea that exists only in our minds." I said: “First, if absolute morals are meaningless because it is an abstract entity (immaterial) then you will agree that our minds are meaningless too (same thing). Second, you have denied the existence of absolute laws of morality. But to use the term moral and immoral, right or wrong, should or ought, is to imply the existence of an absolute standard of morality by which to judge the choices of men. Your worldview denies that standard. In your worldview, a moral choice is one that is nothing more than one that is socially popular or personally preferred. Yet, you do not behave that way. As you have said, you refuse to cheat on your wife, you refuse to ignore the misfortune of others, you refuse to be abuse your wife, you accuse the Christian God of immorality, you accuse me of being "arrogant" and "smug," and you accuse Christians in politics of infringing upon individual rights and doing injustice to others. You are appalled (I hope) by infanticide, slavery, and human torture. You consider these choices all to be wrong and in violation of some principle to which you are obligated and you believe others should obligate themselves to these standards as well. You don't treat these principles as simply popular opinions or personal preferences, but as moral laws. That is, you behave AS IF an absolute standard of right and wrong exists. But your worldview contains no such standard. So, rather than sell out to rampant immoral decadence, unchecked self-indulgence, and total moral relativism, at this point at least, you borrow from the Christian worldview in order to function and make sense your hatred of child rape and the like.
2. Laws of logic. You said: "We should be logical in our discussion, not so much because we are obliged to do so, but because it is the only productive method of doing so. If not, the discussion serves neither of us any purpose ." This statement demonstrates that your worldview can't account for that which you must presuppose in order to function. To quote Pearcy again, "that should tell you something." You have denied the existence of absolute laws of logic, though you originally asserted that you and other "freethinkers" are rational (and Christians are irrational). That is a meaningless charge if laws of logic do not exist. A few messages into our discussion, you referred to our arguments as greatly "lacking." Clearly, you mean that we are wrong in our analysis because we are using illogical or irrational argumentation. But to accuse others of being irrational is to assume that an absolute standard of thought (logic) exists. (It is also to assume an absolute standard of morality exists sense you believe we “ought” to bind ourselves to a certain ethic of thought and limit our arguments to those which are reasonable and logical). You have said that you deny the existence of that standard. So, laws of logic do not exist in your worldview. But you need them every single day for basic cognition. You must presuppose them in order to attach a predicate to a subject and make the world, language, thought, math, etc. intelligible. So, you borrow from our worldview, which contains a personal-absolute God who can not contradict Himself (the foundation of logic) in order to function in and make sense of the world as you experience it. You have now explicitly confessed to being in the Kantian paradox when you say that you must use the laws of logic if you want to be understood and if you want to reason with other people, but that you can’t account for their transcendental necessity.
3. Laws of Science. You said: "Why does there have to be an absolute law of anything, be it science, morality, or ethics? I don't see why the cosmos owes us any absolutes." Of course nothing impersonal can owe or provide an absolute anything. But a personal-absolute can and did. You are, I'm afraid, seeing the consequences of your own worldview and it has apparently placed you farther away from objective truth than even Hume was willing to go (though Hume's empiricism could not explain it, even he refused to relinquish his belief in the laws of nature). Now you are thinking consistently, look out. You have denied the existence of absolute laws of science, though you originally asserted that science is your only method for knowledge attainment. But science can't operate unless these laws are presupposed. So, you apparently profess that they do not exist (laws like natural order), but you behave otherwise. You operate AS IF the world were orderly and predictable and had been created that way by an orderly God. Your worldview can't account for an orderly universe, so to function, you borrow from ours.
Basically, you are not despairing at this point in life (unlike Nietzsche for example) like so many consistent atheistic thinkers in the past because you are not living life consistent with your worldview. You are living your life consistent, at some level, with the Christian worldview. You know the truth of God's existence because you can't function apart from it, but you are actively suppressing the truth in unrighteousness (Romans 1). I did this too at one time. You asked for evidence. I think this is strong evidence that God must be presupposed even in building a case against Him. Christian theism allows one to harmonize their behavior with their worldview. It makes sense of transcendental abstract entities and their utter necessity and it makes sense of how everyone actually lives in and experiences the world.