Christian Science is another 19th century concoction that reflects the popular culture of that time. It is basically a Gnostic form of Christianity with a strong whiff of Arianism
The basic premise is that all matter is dead and non-spiritual. The only true being is the “spiritual” being. So when one gets sick, you merely need to remember that all manifestations of the Material World are an illusion and untrue, recall your “True nature” that you are a pure spirit and your aliment or problem will go away in short order.
They reject the Trinity as polytheism and see Jesus as a Great Teacher, an Ascendant Master of sorts who realized the true nature of existence and wanted to teach this “Science” to mankind. He was no more divine than you or I but rather an elevated super dude. This is a throwback to the Arian heresy. God to them is Pure Love, a Spirit and not a person.
Christian Science should be grouped along with two other 19th century pseudo- religions, Mormonism and Theosophy.