I was going to write something little and non-taxing today but that last post about How to Read a Practical Book just won't leave my mind. Don't you hate that!
I don't feel quite satisfied with the difference between Adler's thinking on the crux of a Practical Book and how I think about it. But perhaps the reason my approach seems to differ from Adler's on what is of first importance in reading a Practical Book is that I am thinking of a different type of book than he is. I've been reading books about parenting, homeschooling, exercise, dealing with emotions, organizing, and productivity. He is probably talking about the more theoretical books about economics, politics, pedagogy in general, and so on. The Big Books, not the self-help ones.
Most of the Practical Books I read are self-help or personal improvement -- in other words they are about making better judgments in ordinary life... the goals are fairly obvious, and it is the methods, and the principles that inform the methods, that are in question. In the books that Adler uses as examples, like books about economics or politics or ethics in general, perhaps there is more question about the goals.
Prudence is "right reason applied to practice". Aquinas seems to say (if I am understanding him rightly) that prudence itself does not determine the ends or goals. The reason for this is that the ends or goals reside in the appetite, not in the intellect per se. The appetite is drawn to the apparent or real good, and prudence deals with how to actually get to that good.
If I didn't already have an inclination towards the goal or good thing presented in the book, I probably wouldn't read it. So while the goal may be the thing upon which everything else turns, as Adler posits, it probably isn't the biggest intellectual problem to solve for me as I read the book, since I already resolved the question to some extent by deciding to read the book. Still, it is probably useful to consider exactly what specific "vision" the author has of the goal. For example, I wouldn't be too sympathetic with parenting books that thought parenting was all about fulfilling oneself, or about making children into mechanically obedient little soldiers.
That's where I will leave it for now.
Maybe I will read Aquinas's treatise on Prudence. It is winter (almost) and I have lots of time.