According to the Collins COBUILD Idioms Dictionary, 3rd ed., the idiomatic expression "two sides of the same coin" implies that two things, elements, philosophies, or ideas that are complete opposites of each other can actually coexist within one same.

Additionally, this also implies that such different elements may be interdependent, that is, that their differences help to add value to the situation in which they both coexist.

Let's illustrate: Comedy and tragedy could be considered two sides of the same coin. This "coin" could be theater, literature, and other disciplines.

Comedy and tragedy are different, but they both coexist in theatric arts (for example).

Moreover, their differences are interdependent, because both help strengthen theater as an art, thus illustrating the power of interpretation and the mimicry of human emotions.

This said, it is also safe to say that fiction and reality are two sides of the same coin. These "two sides" can coexist in different disciplines: literature, theatric art, storytelling, and more.

Without reality, we wouldn't be able to know how to appreciate fiction and vice versa. Fiction stems from reality, because it is an interpretation of it. Hence, fiction would not come to fruition without the existence of a reality in the first place.

Another reason why reality and fiction are two sides of the same coin is because they are equally necessary in literature as well as other media. Some audiences gravitate toward non-fiction (reality) while others prefer fiction. Furthermore, audiences can choose to explore a fictional story by studying the real events that may have inspired a fictional account of it.

In all, fiction and reality can be considered to be two sides of the same coin for the following reasons:

• They are equally important and influential
• They can complement each other, regardless of their differences
• Both genres have their own unique value and hold their own weight.