How does sin darken the intellect?
Question: In a recent response you wrote that sin darkens the intellect. How and why does this happen?
— Peter Tate, Long Beach, California
Answer: We have all had the experience of being in a dark room — say a theater — and emerging into a bright, sunlit day. Our eyes hurt, and we complain of the harshness of the light. But of course, the light is not harsh, and many of the people around us who have not been in the dark room enjoy the light and are not bothered by it at all. The problem is within us; we have become accustomed to the darkness, and thus the light seems obnoxious.
Now, this is an analogy for what happens to us, morally speaking. To the degree that we indulge the dark error of sin, we accustom ourselves to moral darkness. Our thinking becomes distorted, and the light of truth seems obnoxious, even painful and hateful. To those who hate the truth, the truth seems hateful. And unless one rouses themselves to become reacclimated to the light of truth, they retreat even further into the darkness as a preference.
Jesus says: “And this is the verdict, that the light came into the world, but people preferred darkness to light, because their works were evil. For everyone who does wicked things hates the light and does not come toward the light, so that his works might not be exposed. But whoever lives the truth comes to the light, so that his works may be clearly seen as done in God” (Jn 3:19-21).
St. Paul also speaks of “those who suppress the truth by their wickedness. For what can be known about God is evident to them, because God made it evident to them. Ever since the creation of the world, his invisible attributes of eternal power and divinity have been able to be understood and perceived in what he has made. As a result, they have no excuse. For although they knew God, they did not accord him glory as God or give him thanks. Instead, they became vain in their reasoning, and their senseless minds were darkened. While claiming to be wise, they became fools. … Therefore, God handed them over to impurity through the lusts of their hearts for the mutual degradation of their bodies. … God handed them over to their undiscerning mind to do what is improper” (Rom 1:17-22, 24, 28).
Here we see that a darkened intellect comes from suppressing the truth that is obvious in the created order and allowing our desires to overrule reason. This leads to vain (empty) thinking, which embraces the darkness even more. Thus the truth is suppressed, and the moral confusion and error are not suppressed. This permits the darkness to grow as it snuffs out the light of reason.
There follows aversion to the light and even a hatred of it. St. Paul notes the further tendency as the darkness grows to justify our sin: “For the time will come when people will not tolerate sound doctrine but, following their own desires and insatiable curiosity, will accumulate teachers and will stop listening to the truth and will be diverted to myths” (2 Tim 4:3). And thus, the darkness grows even more as the light of truth is further banished from the minds of unrepentant sinners. At some point the mind is all but wholly darkened.
So here is the condition of many who surround themselves with worldly teaching and indulge the deceits of sin. Pleasure overrules all and any limits seem obnoxious. Experts and plausible liars are sought to further reinforce the deception. The darkness is preferred and grows ever deeper. The mind goes on holiday.