Rationalism and Sentimentalism as a Topic of Empirical Research

According to rationalists, the ability to make moral judgments depends on reason, while according to sentimentalists, it depends on affect. A recent development in this debate is the usage of empirical evidence to support rationalist and sentimentalist positions. This raises two questions, which will be addressed in this thesis.
First: Can empirical evidence contribute to the debate between rationalism and sentimentalism? I will argue that empirical evidence is relevant for at least the question whether the process that results in moral judgments depends on reason or affect. Moreover, I will argue that empirical research can use a concept of ‘moral judgment’ that both rationalists and sentimentalists will likely accept. Such empirical research can be used to adjudicate the debate between the two sides.
Second: How can we compare rationalist and sentimentalist positions on empirical support? To answer this question, I make use of causal graph theory. We can compare the empirical support of different positions by representing them as causal models and consequently inferring predictions from these models. It turns out that there is currently a lack of empirical data to compare the empirical support of even straightforward positions. Moreover, this method illuminates which issues prevent us from making clear predictions. For instance, the distinction between rationalism and sentimentalism can be made in two different ways: on basis of causal structure and on basis of causal impact. In the conclusion, I propose a research program to further examine the link between empirical evidence and philosophical debates.