In this paper I examine the argument by H. Beebee and N. Sabbarton-Leary that Brian Ellis’s scientific essentialism is based on the “abuse” of the necessary a posteriori. I will first briefly survey various attempts to resist what I will call the “Kripkean essentialist argument” to locate Beebee’s and Sabbarton-Leary’s position properly. After that I will argue that Beebee’s and Sabbarton-Leary’s argument is not successful; in particular, I will argue that under the most natural interpretation of their position it is not internally coherent, and that their argument is based on a superficial understanding of Kripkean necessity a posteriori.