1.5 Rules of the Road to Scientific Knowledge about Politics
RULES OF THE ROAD TO SCIENTIFIC KNOWLEDGE
In the chapters that follow, we will focus on particular tools of political
science research. As we do this, try to keep in mind our larger purpose –
trying to advance the state of scientific knowledge about politics. As scien-
tists, we have a number of basic rules that should never be far from our
Focus on causality.
Don’t let data alone drive your theories.
Consider only empirical evidence.
Avoid normative statements.
Pursue both generality and parsimony.
Focus on Causality
All of Chapter 3 deals with the issue of causality and, specifically, how we
identify causal relationships. When political scientists construct theories,
it is critical that they always think in terms of the causal processes that
drive the phenomena in which they are interested. For us to develop a
better understanding of the political world, we need to think in terms of
causes and not mere
. The term covariation is used to describe
a situation in which two variables vary together (or
). If we imagine
, then we would say that
covary if it is
the case that, when we observe higher values of variable
, we generally
also observe higher values of variable
. We would also say that
covary if it is the case that, when we observe higher values of variable
we generally also observe lower values of variable
It is easy to assume
that when we observe covariation we are also observing causality, but it is
important not to fall into this trap. (More on this in Chapter 3.)
Don’t Let Data Alone Drive Your Theories
This rule of the road is closely linked to the first. A longer way of stating
it is “try to develop theories before examining the data on which you will
perform your tests.” The importance of this rule is best illustrated by a silly
example. Suppose that we are looking at data on the murder rate (number
A closely related term is