Here is a quotation from the book: “Sometimes she (Valentine/Demosthenes) read Peter’s Lock essays and found herself annoyed at his obvious blindness..”
This passage refers (meaning alludes) not only to the false personae that Valentine and Peter have given themselves (and the essays they have been posting online) but also to the two original philosophers whose names they have adopted. Demosthenes was a Greek philosopher who opposed expansion of political power over the individual; Locke was an English philosopher, strongly arguing for a free intellectual spirit, a proponent of liberal classicism. The two siblings argue small philosophical points, getting others to buy into their political leadership, much like Ender is doing in the training camp. Valentine here alludes to both the historical figures, the current debate between siblings, and the theme of the book—to what degree does individual free will have an effect on political, governmental, bureaucratic forces?