In my view, economics aspires to be an evolutionary science but does not always actually act as such a science.
In order to discuss this issue, we must first understand what is meant by “evolutionary” in this case. An evolutionary science is one which is driven by data and not by faith. It is also one that can change over time as needed. Economics does not always meet either of these criteria.
First, we must ask whether economics is driven by data and not by faith. I would argue that this is not always the case. Economists do, of course, examine tremendous amounts of data. However, they do not always do so, in my view, with completely open minds. When economists study an issue they have to do a great deal of interpretation. For example, an economist who wished to determine whether President Obama’s economic stimulus plan was a good thing would have to determine what would have happened to the US economy if the plan had not been put into action. This is, of course, impossible to know. As another example, economists may be asked to predict the impact of a tax cut on the economy. In trying to do this, they have to make all sorts of assumptions about how the economy will work. The choices they make tend to be driven as much by their beliefs as by hard data. In this way, economics often fails to be truly evolutionary.
Second, we must ask whether economics is able to change in the face of new evidence. In the past, there have been times when it proved able to do so. The major example of this was after the Great Depression. Before the Depression, the dominant paradigm in economics was classical economics. After the Depression, economists moved towards Keynesian interpretations of economics. This was a clear change that was driven by the “facts on the ground” of the Depression.
However, it is not clear that economics has continued to evolve. There has been no major shift in economic thinking since the “Great Recession” of 2007 to 2009. Instead, this downturn has simply been used as another cause of argument between liberal and conservative economists. They appear to be more interested in defending their own “faiths” than in finding new ways to think of the economy.
In these ways, I would argue that economics is not always an evolutionary science. There are times when it is able to change and act as an evolutionary science, but it does not always do so.