Fictional experimental modeling in biology: In vivo representation.

It is commonly held that in vivo biological experimental models are concrete and non-fictional. This belief is primarily supported by the fact that in vivo studies involve biological models which are alive, and what is alive cannot be fictional. However, I argue that this is not always the case. The design of an experimental model could still render an in vivo model fictional because fictional elements and processes can be built into these in vivo experimental models. These fictional elements are essential parts of a credentialed fiction because the designs of in vivo experimental models are constrained by imaginability, conceivability, and credit-worthiness. Therefore, despite its fictionality, it is credible for an in vivo experimental model to stand in for the phenomenon of interest.