Rational thinking without God is not possible. Many people assume that they are able to think rationally without God. They think that they can trust their own reasoning. Many make their case that evolution could build and develop rationality through trial and error starting from basic survival instincts of finding food, avoiding danger, and finding a mate. This trial and error could over time develop reasonable thinking over many generations. However, this is not probable.
This unbeliever is missing the point. This person is assuming that “natural selection” would not also accept lies necessary for survival. In this system, evolution would still allow falsehoods for survival. Therefore, the evolved brain is susceptible to lies and falsehoods that deny reality. No trial and error from others can attest truth and overcome lies if humanity evolved together to accept the same lies for survival. While evolution of the brain is “possible,” it is not probable, because this idea undermines the ability to perceive any truth without errors. Proposing that evolution and natural selection can accept lies for survival and produce rationality and an accurate perception of reality is self-defeating. However, that is not the response this is not an initial point to make to an unbeliever.
First, I find that I must respond by leading unbelievers from a reasonable view of God to presenting the gospel of Jesus’s death, burial, and resurrection. Paul preached Jesus and the resurrection before the Epicureans and Stoics in Athens (Acts 17:18).
Second, the unbeliever tries to reason in the futility of one’s mind darkened in understanding, because they are harden and callous in heart by lewdness and sexual impurity (Eph 4:17–19; cf. Rom 1:18–28). The apostle Paul knew the philosophers in Athens were suppressing the truth (Rom 1:20). However, he reasoned about what is not true about God to present the ultimate truth that God will judge the world by a man giving assurance by raising Him from the dead. Paul’s reasoning brought everyone again back to the gospel of Jesus’s resurrection (Acts 17:30–31).
Further discussion may then include addressing the improbability of evolution producing rationality. Yes, the atheist can account for rationality via possibility. In agreement with observation, one could argue that evolution would produce brains that are in some part rational and irrational for survival. The human mind is fallible. However, I do not see how evolution can account for the *reliability* of rationality — relying on one’s ability to think logically. Can someone account for rationality using rational thought? One cannot prove rationality with rational thought and avoid circular reasoning. Reasoning cannot rely on a hypothesis for evolved rationality to prove that humanity’s rationality is reliable.
Rational thinking cannot be based on survival alone or on oneself but absolute laws of reasoning. Atheists are placing rationality for survival over rationality for reality. Reasoning for survival does not equate to reasoning by what is factual and true. Reasoning for survival does not always produce moral reasoning. Absolutes for logic and morality require an absolute standard, and the only option is the God of the Bible. Because of the fallibility of humanity, humanity needs a reasonable and moral corrective — the holy nature of God as revealed in His Word.
This comes down to the basis of reasoning. Without the God of the Bible, no one can account for the basis of rationality — the laws of logic. They cannot account for the unchangeable nature of logic. Logic cannot begin without logic, and so logic’s existence must be timeless and constant. However, logic cannot exist without the mind thus requiring an eternal mind. Only the God of the Bible is eternal.
The human mind cannot know anything without fallibility. Without the infallible and sinless nature of God as in Jesus Christ, no one can think rationally or know that they really know anything with certainty. Only with God can humanity rely on rational thinking to know what is true. Without God, people do not have the rational ability to know what is true either according to evolution or when evil works keeping one from seeing God’s light in Christ (John 3:19–21).