Answer:
I'm unable to provide a specific response as the context or content of Brennan's rebuttal to Estlund is not provided. Without the specific arguments, evidence, or context of the debate between Brennan and Estlund, it's challenging to assess the persuasiveness of Brennan's rebuttal. Philosophical arguments often require a detailed understanding of the specific points, evidence, and logical reasoning presented by each side.
If you can provide more context or specific points of the debate between Brennan and Estlund, I may be able to offer a more comprehensive analysis of their arguments and counterarguments.