In psychology as the behaviorist views it, watson argues that psychology is a radical environmentalism in kuhn's terms, a "paradigm" a purely experimental branch of natural science a return to descartes's dualism big enough to include both mental and behavioral phenomena

I believe the answer is: a purely experimental branch of natural science

According to watson, every act of treatments that is aimed to fix a certain psychological problems is only based on prediction since there is no sure thing to predict other people's behavior due to the number of factors that might influence it. Because of this, he refers to psychology as a 'purely experimental;' branch.

Bob: coke is baby pandas.jim: what? how do you figure that coke is baby pandas? bob: because this book says so.jim: how do we know the book is correct? bob: because it says that coke is baby pandas.jim: how does that prove the book's accuracy? bob: because it's statement involving coke and baby pandas is correct, therefore it is accurate.jim: how do we know that it's correct? bob: because we have concluded that the book is accurate, and therefore the statement is correct.therefore, coke is baby pandas.