Throughout history there have been instances where what was thought to be a reality turned out to be an illusion, such as when it was discovered that the Earth is not flat or that the sun does not revolve around the Earth. In both cases, people believed in a misconception for many years because of what they had been told and what the physical senses were telling them. In fact, some people were terrified to sail far out into the oceans, because it was believed that at some point they would reach the edge of the Earth and plummet over a precipice.
Of course, once it was discovered the Earth is round, such people were no longer afraid to sail the seas. This illustrates two basic points about illusions: 1) They are not real; and 2) Because they are unreal, they do not need to be feared.
In the latter half of the 19th century, visual illusions became a topic of much interest. At the same time, the discovery of Christian Science in 1866 by Mary Baker Eddy was also beginning to capture the public’s attention. Christian Science was presenting spiritual insights into the healings that Christ Jesus accomplished, as recorded in the Bible. From a metaphysical standpoint, they could be seen as convincing evidence that sickness is an illusion, rather than a reality.
