This was developed by Searle (1964) who proposed a five stage process of
derivation from the statement of “I promise to pay you five dollars” to “I ought to pay
you five dollars”. Based on whether they take a prescriptivist or descriptivist stance,
philosophers have argued and disputed the logical process by which this was achieved.
How this has been developed is beyond the remit of this paper on environmental
taxation, but suffice to state that there appears to be a link between the scientific
statements and the requirement or obligation to address the problems of climate
change nationally and internationally, and also to address current and future
consequences.