Needless to say, the human race is unique among all God's creatures. A gorilla could look through a telescope, he'd make a terrible astronomer. A chimpanzee could put on a lab coat, I wouldn't ask him find a cure for cancer. If you literally receive something "straight from the horse's mouth", it's not likely to be some sort of profound philosophical truth. Even parrots, which literally can imitate human speech, would be awful at conversation.
This fact caused Darwin quite a bit of distress. In his religion, mankind is not only related to these creatures, but actually shares an ancestral history with them. In his own words, "with me the horrid doubt always arises whether the convictions of man’s mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would any one trust in the convictions of a monkey’s mind, if there are any convictions in such a mind?" (1)
An Evolutionist will struggle to give any justification for why we, as humans, are any better at reasoning than any other animal. I like how some Creationists refer to the human mind in an Evolutionist worldview as a "mutant berry finding ability". The reasoning behind this sarcastic jab is that if Evolution is true, it isn't geared towards the pursuit of truth. In fact, it isn't really geared towards anything. It's just that things which randomly evolve and provide a survival advantage get passed down to one's offspring. Therefore, the absolute best we can say about our ability to seek truth is that we, like all animals, are able to accurately assess truths when that truth provides a survival advantage. For example, "that berry is poisonous" may be true, and therefore those who believe it will be less likely to eat the poison berries and die than those who don't.
But what about non-survival truths? There are so many truths that provide no survival advantage that I am spoilt for choice to give an example. Why do I need to know how far from earth the moon and sun are? What advantage do I gain from knowing how many wives Henry VIII had during his life? Will I die if I don't know the first 20 digits of Pi? Not all truth claims affect survival, and thus there is no reason, in Evolution, to believe I could accurately assess them.
And it gets worse. Sometimes, lies might improve the odds of survival. For example, it is false that all snakes are poisonous. However, if you believe they are, you're at least going to avoid the deadly ones, because you'll avoid them all regardless of how deadly they are. Furthermore, it is a lie that any snakes are poisonous. This might confuse some people, but let me explain. There is a difference between "poisonous" and "venomous". A poison is that which is absorbed, ingested, or inhaled. Venom, by contrast, works through injection. Thus, even a venomous snake is not actually poisonous. Nevertheless, if you make this common mistake by believing a snake is poisonous, when in reality, it is actually venomous, you're still going to do your best to avoid the deadly snake. Therefore, there are scenarios in which believing a lie may be as beneficial, if not more so, to your survival.
What's interesting is that this is the Evolutionary excuse for why religion evolved. Though in their mind, all religions that involve the supernatural are false, Evolutionists nevertheless believe they provided our ancestors with some kind of survival advantage. Now, obviously, I am a Christian. I firmly believe the Bible is God breathed, and is therefore both true and authoritative. I also believe I have good reasons to believe that. Around the world, a fair few people agree with me. Millions, in fact. Including many scientists. Yet, the Evolutionist will say we're all wrong. If such a huge portion of the human race can be so horribly deceived just because we have evolved that way, what possible reason can an Evolutionist have for trusting their own reasoning abilities? After all, they evolved from the same source, with the same purpose (or lack thereof), via the same process. So who are they to believe they can reason better than a monkey, or even a man they perceive as being less intelligent?
Compare this with Christianity's view of reality. First and foremost, Christians believe in a Creator God who possesses the greatest extremity of every good attribute. The moment you introduce such a God into your worldview (or, more accurately, the moment you submit your worldview to such a God), you completely erase this problem.
First, God is a Creator. In fact, He is the Creator. According to John, "...without Him nothing was made that was made." (John 1:3b). So, everything that exists exists because God created it. Hebrews 1:3 also tells us that He upholds all things by the word of His power. In other words, He didn't just create everything, He also sustains it.
God is also omnipotent. He is literally the only limit upon Himself. The Bible tells us that nothing is impossible for God, and He certainly demonstrates His power over nature through what is called "miracles". So, He is both capable of creating and sustaining all things. Furthermore, He is capable of making and, when He deems fit, breaking natural law.
God is Holy. By His very nature, He cannot lie. Also by His nature, He is not the author of confusion (1 Corinthians 14:33).
From all of this, we can be sure that God would create an orderly and rational world. It's not going to be pure chaos, it's not going to be deceptive, God's not going to occasionally slip up and let the moon turn purple etc. In fact, as I have pointed out in the past, the very concept of a miracle requires that natural laws exist. But of course, none of that establishes our reasoning abilities. As I pointed out, all animals live in this world, yet none of them really possess the ability to understand it. And so the question remains as to why we are the exception?
Put simply, it's because we were created to be. Christians believe that the God described above created us in His image with the specific intention that we relate to Him, and that we have dominion over the Earth. On its own, that's more than enough to suggest we have fully functioning reasoning capabilities.
Furthermore, God's revelations treat us as if we do. In fact, it is this that gives us a special form of accountability to Him. The Bible assumes that we will observe creation to the extent that we will understand His invisible attributes. For the Christian, this is great motivation to study creation. It's simple: We want to know God, the Bible tells us creation helps us know God, so we study the creation. For the unbeliever, the Bible tells us creation is just too loud to ignore. The unbeliever is without excuse, because design screams designer.
So, the Christian has the perfect defence of human reasoning. We were designed to reason by an omniscient and omnipotent Creator who actually commands us to test all things and hold on to that which is good (1 Thessalonians 5:21). Evolutionists, by contrast, cannot believe their reasoning abilities are vastly superior to an ape's. In other words, taking Evolution seriously, you can't take arguments that lead to Evolution seriously. By contrast, taking Christianity seriously, you absolutely can take arguments leading to Christianity seriously.
I often like to say that using science to disprove God is like trying to prove the ocean does not exist, and using a fish as proof. It is ironic that the very reasoning skills God gave us so we can relate to Him is so often used to rebel Him instead. The bad news is, there are consequences for this. When you rebel against the Author of life, what punishment is there but death? But death is not what God wants for you.
So, what's His solution? In His mercy, He sent His Son, Jesus, to live as a man. Jesus, unlike the entire human race, never once rebelled against God. Nevertheless, He died as if He had. He did this to take your punishment. Everything you have ever done wrong, Jesus took the punishment for when He died. But He didn't stay dead. On the third day, Jesus walked out of His tomb and out into the sunrise. If you only repent, confess Him as Lord and believe He rose for you, you will be forgiven, and inherit eternal life in His Kingdom.
References
1. Charles Darwin, Letter to William Graham, 1881