What is real?

I recently read an interesting article that discussed the possibility that this whole universe may be nothing but a simulation. Other thinkers have suggested similar theories, and it can be intriguing to try to follow their logic and figure out what they’re talking about.

That article and others like it came to mind when I reread a statement by Mary Baker Eddy in her book Science and Health with Key to the Scriptures. She wrote: “Human mind produces what is termed organic disease as certainly as it produces hysteria, and it must relinquish all its errors, sicknesses, and sins. I have demonstrated this beyond all cavil. The evidence of divine Mind’s healing power and absolute control is to me as certain as the evidence of my own existence” (p. 177).

Those articles about the nature of the universe and this statement by Mrs. Eddy wrestle directly and indirectly with cause and effect. What is really real? What can I be sure of?