The project of constructing a history of philosophy comprises at least three projects, two of which are explanatory and one evaluative. First, a history of philosophy seeks to explain our present circumstances, especially their intellectual foundations. As A. C. Grayling puts it, “Philosophy’s history … is a retrospective construct. It is chosen from the wider stream of the history of ideas in order to provide today’s philosophical concerns with their antecedents” (A. C. Grayling, The History of Philosophy, xv).
Tracing the origin of an idea explains how we got where are. It also demonstrates that the intellectual problems we presently face are not novel. They are problems with an intellectual history. Often we think that no one has considered answers to our present questions. As a perusal through the history of philosophy demonstrates, this is seldom true.
The second part of the explanatory project is to explain the causal connection between ideas and historical circumstances. As Bertrand Russell writes,
“To understand an age or a nation, we must understand its philosophy … There is here a reciprocal causation: the circumstances of men’s lives do much to determine their philosophy, but conversely, their philosophy does much to determine their circumstances” (Bertrand Russell, A History of Western Philosophy, xiv).
To understand what happens in practice, one has to understand what is going on in theory. History is a baffling subject in part because we can’t understand why people do what they do. If all we study is the activities of people and their nations, we’d be none the wiser. What illuminates activities is the ideas from which they spring. Hence, to understand the flow of history, one must study the flow of thought. As Francis Shaeffer so elegant puts it,
“The results of [people’s] thought world flow[s] through their fingers or from their tongues into the external world. This is true of Michelangelo’s chisel, and it is true of the dictator’s sword” (Francis A. Shaeffer, How Should we Then Live? 19).
Not only does a history of philosophy explain the activities of people in history, it also helps explain other ideas in related domains. For example, one can apply this project to the theological task. Philosophical advances almost always impact the theological task. Most of the greatest theologians were either astute philosophers themselves or relied heavily on others who were. As Diogenese Allen suggests, “Everyone needs to know some philosophy in order to understand the major doctrines of Christianity or to read a great theologian intelligently” (Diogenes Allen, Philosophy for Understanding Theology, ix, xi).
A study of the history of philosophy will provide explanations for our present situation and for the activities and doctrines of previous generations. But a history of philosophy isn’t merely a description of the domain over time. It should also include a degree of evaluation. One can’t just watch philosophy from a distance, one ought to step into the project both as a historian and as a philosopher. Anthony Kenny forcefully argues that whichever one’s interest, philosophy or history, one will have to partake in the other:
“The historian of philosophy, whether primarily interested in philosophy of primarily interested in history, cannot help being both a philosopher and a historian … The historical task itself forces historians of philosophy to paraphrase their subjects’ opinions, to offer reasons why past thinkers held the opinions they did, to speculate on the premises left tacit in their arguments, and to evaluate the coherence and cogency of the inferences they drew … On the other hand, the historian of philosophy must also have a knowledge of the historical context in which past philosophers wrote their works” (Anthony Kenny, A New History of Western Philosophy, xiii-xiv).
The history of philosophy demands both an assessment of philosophical ideas and a recognition of their context in the unfolding of history. Kenny suggests that evaluation of an argument may be possible without any reference to its historical context or intellectual antecedent but, more often than not, it will require that information to explain assumptions and key premises given in the arguments.
Developing a critical eye for good argumentation is fundamental for any kind of intellectual activity. As Craig Batholemew and Micheal Goheen point out, evaluations begin by assessing points of view on their own terms before turning to evaluate them from a particular perspective:
“… we try to understand and do justice to the philosophies we examine on their own terms before turning to critique … Our critique takes two forms. The first is to attend to contradictions internal to particular philosophies … The second is to place the work of a philosopher with the context of the grand story of the gospel” (Craig Bartholomew and Michael Goheen, Christian Philosophy: A Systemic and Narrative Introduction, 25).
The best evaluations of views are comprised first of a generous interpretation, then an internal evaluation and an assessment from a given perspective (in this case, a Christian perspective).