Stephen Van Evera's Guide to Methods for Students of Political Science (1997):
P. 5:
Chapter 3 also reflects my view that political science should embrace the task of historical explanation among its missions. Historians should not be left alone with the assignment. Many historians are leery of generalizations, hence of the use of general theories; yet theories are essential to historical explanation. Many are averse to explicit explanation, instead preferring to "let the facts speak for themselves." Many are averse to writing evaluative history that judges policies and policymakers. Political science should step in to fill the explanatory and evaluative gaps that are left by these quirks in historian culture."
P. 93:
Moreover, scholarship of types 5 and 6 ("historical explanatory" and "historical evaluative") lacks a friendly home in other disciplines, which leaves this work to political scientists. Some historians are averse to explicit explanation, instead preferring to "let the facts speak for themselves." Others will elaborate a preferred explanation, but they rarely set contending explanations against one another, as one must to fully evaluate an explanation. Historians are also (with some exceptions)9 generally averse to writing evaluative history. However, without explanatory historical work history is never explained; and without evaluative historical work we learn little from the past about present and future problem-solving. Hence some field should accept these tasks. I nominate political science.
Is this an accurate characterization of history (leery of general theories, averse to evaluation, preference for "letting the facts speak for themselves")?
I don't think I've ever met a historian who didn't understand the role of general theories, or one that thought approaching historical analysis from particular lens (such as marxism) was inherently bad.
Why are historians wary about using general theories to explain and evaluative historical events?
Some are, and some aren't, depending on what their particular area of focus is and what they are trying to accomplish. While many historians would argue that they are trying to get as close to the truth as possible, how they go about doing that is telling about their theory of history. The general way we analyze history has changed over the years, and this is part of the theoretical framework historians develop as they go through school on their own practice.
Why are they wary of evaluation?
Anachronistic thinking can creep into such evaluations. That said, I have seen plenty of historians make evaluations. Hell, some of the most famous, such as Gibbon, were pretty explicit.
Doesn't that leave significant gaps in history scholarship?
The more 'theoretical' and 'evaluative' a piece is, the more likely it is to fall outside of history, strictly speaking. Political scientists can be historians as well, as can sociologists, anthropologists, and even biologists. They fill in those gaps.
Is there a debate in the field on this topic?
There is debate in every field. :)
I agree that historians are far less interested in theory than many others in the humanities. Certainly compared to Literature, sociology or anthropology. I don't agree about being resistant to evaluation. Most historical debates are evaluative; such as responsibilities for the First World War. We insist on having these debates in their original context. This can be misunderstood by critics. Something similar is involved in the reluctance to use a lot of theory. It often just looks like the theorist is imposing a modern set of rules on the past. A lot of literary theory in particular seems to me to be esoteric and pointless. That said historians have used a lot of gender theory for example to help them interpret sources.