Which of Descartes's ideas put him in direct conflict with the Church?

Descartes's idea of dualism, which posits a separation of mind and body, challenged the Church's teaching on the unity of body and soul. The concept of innate ideas also clashed with the Church's belief in knowledge derived from religious teachings and revelation. Additionally, Descartes's emphasis on human reason and doubt as a foundation for acquiring knowledge went against the Church's emphasis on faith.