More than anything else, this is a book about rationality, how to understand the way our sense of the rational maps to sound decision making and how it may map to unsound decision making.
For Gilboa, rationality is not an objective state of flawless thinking. Instead, he understands “rational” to describe a process of thinking that a person is “comfortable with” and “not embarrassed by” (5), which makes it much more subjective than I am entirely comfortable with. He does acknowledge that rational thinking is that which is stable and coherent but with a person’s own sense of standards (6) instead of some standard or expectation outside the self. To me, this definition seems to describe a way of thinking that is “reasoned,” in that it is the result of a process of deliberate thinking, but that may still be flawed because the reasons are just not good. To call thinking “rational” seems to require the application of a set of principles of necessity or intellectual obligation to some standard that is outside the subjective. There are plenty of situations where the correct decision is counter-intuitive and uncomfortable but ultimately discoverable through systematic thinking.
In spite of this difference, I do think that Gilboa offers a look at the principles guiding rational thought and decision making. His point, if I read him correctly, is to show how our intuitions can map onto those frameworks. And at some level this makes sense — we do try to maximize utility, minimize risk, and try to win games or choose outcomes of equilibrium when outright winning is not possible. And we come to these conclusions by assigning value, utility, or some other kind of preference to desirable outcomes and we assess the potential for the various risks that threaten those positive outcomes. In that sense, rational decision making does appear intuitive and subjectively felt. The math that explains those intuitions and subjective preferences coalesce into models that appear to offer normative rules of logic but perhaps those rules are just the result of retrospective thinking about enough decisions where we know the outcome and where the law of large numbers leads us to see how the sum of those decisions converges on the mean, describable with a tidy mathematical formula.
The value in this book is that Gilboa builds up a vocabulary of decision theory and descriptive statistics that allow readers to develop a literate awareness of the factors that may be driving their sense of rational choice. In this way, the book is like Susan Stebbing’s Thinking to Some Purpose, which similarly tried to build a person’s meta-awareness of their own thought process and how they could be led toward or away from sound conclusions.