This sequence aims to explain Functional Decision Theory (FDT) in an intuitive way, with as little math as possible. The posts in this sequence heavily draw upon Eliezer Yudkowsky and Nate Soares’ article Functional Decision Theory: A New Theory of Instrumental Rationality. Although this article provides an excellent introduction to FDT, this sequence offers a more informal introduction, starting out with introducing Causal and Evidential Decision Theory and their shortcomings in order to show the strength of FDT.