I am a strong believer in One Economics (but Many Recipes), because conventional economics, as I have argued here many times, provides powerful analytical and quantitative tools for the analysis of social reality. Every assertion about the world is based on some theory and underlying model. It is far better to make these explicit. Mathematics and statistics are indispensable tools in this.
This is of course not a widely shared view, especially among "heterodox" economists. Erik Reinert, who has written an interesting book called How Rich Countries Got Rich ... and Why Poor Countries Stay Poor has a web site that develops what he calls the "other canon." A table in the book and on the web site lists the differences between mainstream economics and the "other canon". Here it is:
I don't know. I understand where Reinert and his collaborators are coming from, but I cannot agree with their characterization of the conventional approach. Is mainstream economics really stuck in the perfect information/perfect foresight mold? Ignores man's wit and will? It doesn't handle novelty endogenously? Cannot handle dynamics? And this is just the beginning. Sorry, but this is not the economics I recognize or think that I practice.
Some of the items on the list seem more fitting. For example, it is correct that mainstream economics has a penchant for abstraction. I don't think this is a bad thing. Simplifying things is a way of understanding them. Every theory is a simplification. What is often billed as a "theory that is meant to capture complex reality" is often not a theory at all, but just description.