Wade's speculation disclaimer

From Chapter 1 of Nicholas Wade's A Troublesome Inheritance:

“Since much of the material that follows may be new or unfamiliar to the general reader, a guide to its evidentiary status may be helpful. Chapters 4 and 5, which explore the genetics of race, are probably the most securely based. Although they put the reader on the forefront of current research, and frontier science is always less secure than that in the textbooks, the findings reported here draw from a large body of research by leading experts in the field and seem unlikely to be revised in any serious way. Readers can probably take the facts in these chapters as reasonably solid and the interpretations as being in general well supported. 

“The discussion of the roots of human social behavior in chapter 3 also rests on substantial research, in this case mostly studies of human and animal behavior. But the genetic underpinnings of human social behavior are for the most part still unknown. There is therefore considerable room for disagreement as to exactly which social behaviors may be genetically defined. Moreover, the whole field of research into human social behavior is both young and overshadowed by the paradigm still influential among social scientists that all human behavior is purely cultural. 

“Readers should be fully aware that in chapters 6 through 10 they are leaving the world of hard science and entering into a much more speculative arena at the interface of history, economics and human evolution. Because the existence of race has long been ignored or denied by many researchers, there is a dearth of factual information as to how race impinges on human society. The conclusions presented in these chapters fall far short of proof. However plausible (or otherwise) they may seem, many are speculative. There is nothing wrong with speculation, of course, as long as its premises are made clear. And speculation is the customary way to begin the exploration of uncharted territory because it stimulates a search for the evidence that will support or refute it.

"The reader may also wish to keep in mind that this book is an attempt to understand the world as it is, not as it ought to be."