Men are not improving; they are growing increasingly worse! Here God is acknowledging that human nature is prone to progressive degeneration. There are two related reasons for this:
1. Sin has a drug-like addictive quality in that the sense of relief, satisfaction, or pleasure derived from it does not last. Thus, to receive the same amount of pleasure as before one has to sink deeper and deeper into the perversion.
2. Closely related is that a person must commit the sin more frequently because the duration of satisfaction decreases the longer one continues in a sin.
Because of this inclination toward increase, social and religious barriers to immorality within the individual and community gradually come down. Therefore, each new generation provides a more fertile breeding ground for sin because human nature provides no real impediment to it. As sin becomes more acceptable in a society, the people have more difficulty recognizing it.
To the Christian, this sets up a disturbing possibility. Suppose twenty years ago we were fifty percent more righteous than society, and today we are still fifty percent more righteous. But because standards in society have declined steeply, we have slipped far ourselves! People who do not understand sin call evil good and good evil until society reaches the point illustrated in Genesis 6:5: "Then the LORD saw that the wickedness of man was great in the earth, and that every intent of the thoughts of his heart was only evil continually." In cultures all over this globe, mankind is rapidly approaching conditions that are just like the days of Noah (Matthew 24:37).