A reason to be strict about this definition of science is that people, who would argue that nature is basically random, would also tend to reject deterministic results of science. A deterministic result of science is for example (1) that divergent indexation of tax exemption and the standard of living causes a tax void, and (2) that the existence of a tax void can be used to ‘abolish taxes’ without costs. It would be a pity if this result were to be rejected because of a fundamentalist ‘random view of the world’.
From stylized fact to definition
Our subject is the political economy of western welfare states, and in particular employment and inflation aspects. This subject is quite complex, and we must be modest about our results. Of course we can use statistics of the national accounts, and thus indirectly we use the statistical labour of thousands of statisticians, and indirectly the results of thousands of firms and of millions of citizens that filled in their tax forms. Economic literature provides a wealth of models and interpretations of these data. In my case, I also rely on my own experience in constructing a national economic model. All this, however, does not mean that we can forget about modesty, on the contrary. Nevertheless, it is my conjecture that we can achieve a more enduring result than just awareness of complexity.
What is interesting in economic discourse is the concept of ‘stylized fact’. When an economist observes some regularity, he is rather inclined to use that term. We shall use the term more conservatively, and we are hesitant about observing regularities. But we also can fruitfully employ the term when there is a regularity indeed. In some cases, when the regularity is so strong that our loss function comes in the epsilon zone, then we even can switch to definitions.
So we adopt the methodology:
(a) state what we consider to be the stylized facts
(b) define our concepts so that the stylized facts are covered by definitions
(c) develop theorems and proofs
(d) link back to conclusions about reality.
A proposition - as a statement on reality - can be regarded as a mathematical theorem about/within a model of stylized facts. When there is a tautology, we attain truth by definition.