The Simple Explanation just consists in the observation that a judgment will be immune to error through misidentification (IEM) when it is not based on an identification. The Simple Explanation does not itself rule out any candidate theory of de se thought. This chapter discusses IEM relative to the first person more than any other kind of error through misidentification. For convenience, the author uses fp-immunity as an abbreviation (and fp-immune as an abbreviation for the corresponding adjective). James Higginbotham and François Recanati mostly speak of 'thoughts' as exhibiting or failing to exhibit IEM. It is clear that both beliefs and judgments can exhibit IEM. The most plausible explanation of fp-immunity, the Simple Explanation, imposes no tight constraints on an account of the de se. Constraints on such an account need to be gathered from somewhere else.