Stranger in a Strange Land

While reading Robert Heinlein's Stranger in a Strange Land, I found one of the most important aspects of the book to be the many subtle conversations the author has with the reader. There are many points where Heinlein has two or more characters talk to each other for an extended period of time on a subtopic, such as art, history, literature, or economics, to name a few, and I believe there was more to this than a simple character conversation. Heinlein is attempting to engage the reader directly by finding something that they will likely be interested in and offering his views to them. When his characters Jubal Harshaw and Ben Caxton speak about art, for instance, it is a chance for Heinlein to offer up his views through Harshaw, while he uses Caxton to give the kind of general responses the reader might feel like giving. Stranger in a Strange Land is almost entirely a philosophical discourse between character to character on one level, and author to reader on another. This has the effect of pulling the reader in, as you start to feel less like you are reading and more like you are being spoken to. This is strongest with the main character, Valentine Michael Smith, who always speaks directly about humanity's flaws and ways to overcome them; Heinlein is using him to tell you what might be wrong with you, and to comfort you by offering you ways to change. This is a strange approach that I have never found in any other book that I have read, so I noted it as something that specifically interested me about Stranger in a Strange Land.

Does an author who attempts to change the opinions of his readers change the very nature of the story in his/her novel?