Excellent response. Another example of a famous philosopher changing his mind publicly a lot is Bertrand Russell; he changed his views in all areas of philosophy, often more than once:

• In metaphysics, he started his career as an Absolute Idealist (believing that pluralities of objects are unreal and only an universal spirit is real); then became convinced of the reality of object and extended his newfound realism to relations and mathematical concepts, becoming a Platonist of sorts, and later became more and more of a nominalist, though never a complete one.

• Concerning perception, after switching first from idealism to a sort of naive realism, he developed a new theory in which physical objects reduce to collections of sense-data, and later repudiated this theory in favor of one where physical objects cause sense-data.

• He also changed his views on the self, from seeing it as an entity to reducing it to a collection of perceptions.

• Finally, in metaethics, he started out believing that the Good was an objective, independent property, but was convinced to abandon this view and become more of a naturalist and subjectivist by the arguments that Santayana raised against him. (Santayana's critique can be read here and is a fascinating early version of the kind of metaethical view accepted by Eliezer and most LWers).