The aim of this essay is to analyze the fregean notion of thought and discuss the problem of cognitive dynamics. To this end, I shall take the following steps. To begin with, I analyze the very notion of thought as put forward by Gottlob Frege. Frege s theory is to be contrasted with its main alternative, that is, Russell s account of thoughts or propositions. I proceed, then, to discuss the issue of cognitive dynamics, which is the issue of how it is that the subject is able to maintain his beliefs through context changes. This is, I take it, a difficulty that any theory of thought has to face. My aim is to assess the solutions devised both by the Fregeans and the Neo-Fregeans, showing that they have merits as well as weaknesses. I also question the viability of the would-be solutions and tell which seems the soundest. Finally, I discuss a specific type of thought the issue of cognitive dynamics concerns too: the so-called I-thoughts, or de se thoughts, that is, thoughts that have as their object the very subject referred to by the first person pronoun I . They are a special case of thoughts for which the issue of cognitive dynamics holds too, although they present their own characteristic features. One of these features is the immunity to error through misidentification, already discussed in the work of Gareth Evans. Other characteristics of the I-thoughts will also be discussed, with a view to figure out what seems to be the best way to account for their nature and the cognitive dynamics they involve.