Quine articulates the problem of circularity inherent in naturalized epistemology when it is treated as a replacement for traditional epistemology. If the goal of traditional epistemology is to validate or to provide the foundation for the natural sciences, naturalized epistemology would be tasked with validating the natural sciences by means of those very sciences. That is, an empirical investigation into the criteria which are used to scientifically evaluate evidence must presuppose those very same criteria. However, Quine points out that these thoughts of validation are merely a byproduct of traditional epistemology. Instead, the naturalized epistemologist should only be concerned with understanding the link between observation and science even if that understanding relies on the very science under investigation.