I often hear the cult of Christian Science opposed on the basis that it is not Christian and not scientific. Even though it has declined in popularity (many of the well-known adherents are likeliest to be celebrities of yesteryear), it is still well enough established to need to be understood as to why it is heretical to orthodox Christian belief.
Christian Science is a form of metaphysical idealism, founded by Mary Baker Eddy in the 1860s. She rejected the Christian doctrines of her upbringing and began writing about her newfound beliefs after an accident nearly claimed her life. Her first book Science and Health was published in 1875 and led to the establishment of the first Christian Science church in Boston, Massachusetts. It has declined in popularity in recent decades and now probably has fewer than 200,000 members globally, although a prohibition on the keeping of membership statistics makes it difficult to determine the exact number. The Christian Science Monitor has been a well-known publication of this movement.
Christian Science claims that sin, sickness and death are illusions since everything is ultimately God. Therefore, that which cannot be of God can be conquered by correct thinking. This also effectively means, though, that matter cannot really exist, despite Christian Science’s rejection of pantheism. Eddy taught that God was the divine principle, and she denied that God (‘it’) was also a personal being (despite the Bible repeatedly referring to God in personal terms throughout). Furthermore, she taught that prayer to a personal God could only hinder spiritual growth, since prayer was about belief correction.
Of course, the Bible also teaches that God created a material universe (Genesis 1, Psalm 102:25, Isaiah 44:24). It also teaches the reality of sin (Genesis 3) and its devastation of the Creation (Romans 8:20). Denial of sickness has led to unnecessary deaths and accusations of malpractice and negligence and Christian Science healing is therefore now considered an additional help to the use of conventional medicine, rather than a preferred alternative.
In the absence of sin, Eddy therefore sought to have people realise their freedom as they came to realise their sinless state, since people were to be regarded as already being saved with an everlasting salvation and therefore in no need of redemption (despite Jesus calling sinners to repentance, as in Matthew 9:13 and our need to confess and believe in Romans 10:9-10). Christian Science ultimately views humanity as spiritual due to being created in the image and likeness of God, despite the reality of our physical condition and death being obvious throughout scripture.