The simultaneous loss of both was not a coincidence. The spiritual apostasy and wickedness of man diminished the enlightening power of the Spirit of the Lord. Because so much of humanity’s secular knowledge comes from the Spirit of the Lord, this diminishment affected mankind not only spiritually, but secularly as well. As the power of the Spirit of the Lord waned during the apostasy, so too did mankind’s ability to receive enlightenment.
The spiritual apostasy contributed to the decline of secular knowledge in another way. During the apostasy mankind tried to compensate for the loss of spiritual enlightenment and apostolic authority by appealing to human reason. The philosophical contributions of ancient Greek scholars were monopolized by misguided theologians and scholars who wanted to settle doctrinal disputes and make Medieval Christianity more appealing to the masses. The works of famous scholars like Plato and Aristotle now served the interests of a powerful apostate church.
Because the church controlled a large number of educational institutions and most medieval scholars were clergy members, few people dared interpret Classical Greek principles in a manner contrary to the teachings of the church. Those who attempted to enlighten mankind faced reprisal from the church if their ideas opposed church doctrine. The hijacking of Classical Greek philosophy by dogmatic religious authority, diminished blessings from the Spirit of the Lord, and the loss of priesthood authority all combined to create the Dark Ages.
(Source: Truth & Science)