Two important points:
1. Firstly, the summary of these different perspectives above runs the risk of giving the impression that philosophy and theory come first, prior to methodology.
2. Secondly, in the summary provided above, physical geography features in the earlier approaches to research (positivism, critical rationalism and complexity theory, critical realism).
a. Human geography runs throughout, but the later approaches seem to be solely the preserve of human geographers.
b. This raises the contentious issue of the relation between the two.