 Content Externalism and Self-Knowledge. Externalism is importantly connected with issues surrounding our introspective knowledge of our own mental states. Such knowledge appears to be a priori, or at least privileged, in that it is acquired without relying on empirical evidence or observations. On the face of it, externalism threatens the existence of such privileged knowledge. If the contents of our thoughts are determined in part by our relations to the environment, then one might think that external observations are needed in order to know what we think. But self-knowledge does not come about through empirical investigations. So either, contrary to appearance, we do not really know the contents of our own thoughts or, if we do, externalism is false. (See the entry on  externalism and self-knowledge  for further discussion).