In this case the topic of value is the often fraught relationship between empiricism and rationalism, and the impacts each have on the scientific process, research, education, and how we go about understanding the world.
To operate with one with a complete absence of the other is to expose yourself to huge, often fundamental gaps in your thinking, your arguments, and your plans. This is what the author is ultimately getting at from the direction of the empirical: data, in the form of a large collection of discrete observations, can be used to justify a sea of mutually exclusive claims that may or may not be in accordance with reality, and that's to say nothing about the quality of the data itself.