Over here. Just a few thoughts –
First, the comment from Shawn Ritenour shows that institutions that promote economic and human flourishing cannot be brought to sight through economic science alone. This is why sociology proper is necessary for a holistic groundwork of human flourishing. (See the Introduction to Say’s Treatise, as well as Tracy ‘s Treatise, for more on how economics and sociology relate to one another.)
Second, the statement that GDP per capita is not equal to human flourishing is a fundamental insight of the early Austrian school, as embodied by Menger, Weiser, and Bohm-Bawerk. To quote Menger from Book One, Chapter Four of his Investigations into the Method of the Social Sciences:
Not only in the realm of the ethical world, and of economy, but also in that of natural phenomena, the realistic orientation of theoretical research can lead only to “real types” and “empirical laws.” And in the above point of view, at any rate, no essential difference between the ethical and the natural sciences exists, but at most only one of degree. The realistic orientation of theoretical research excludes in principle, rather, in all realms of the world of phenomena the possibility of arriving at strict (exact) theoretical knowledge.
UPDATE: The above quote was not the one I had in mind when I was writing this post. Here is the quote I did have in mind, from a letter Carl Menger wrote to Leon Walras:
We do not simply study quantitative relationships but also the nature [or essence] of economic phenomena. How can we attain to the knowledge of this latter (e.g., the nature of value, rent, profit, the division of labor, bimetallism, etc.) by mathematical methods? (White, “Methodology”, p. 8)