Is the Second Demographic Transition a useful research concept: Questions and answers

Very wise men, the organisers of this debate. They do not pose a question that is virtually impossible to answer, such as: "Will you please prove that the SDT exists or does not exist", but one that can be answered in a dispassionate and straightforward manner: "Is the Second Demographic Transition a useful research concept?" My an swer is a simple and unqualified "Yes". In my view it is really impossible to under stand the demographic changes that have occurred in Europe, and in many other in dustrialised countries as well, since the mid-1960s, without accepting the idea that the many and very varied changes we have observed in a whole series of demo graphic variables are interrelated and may in their totality be indicative of, and repre sent, the manifestation of a change in demographic regime. Theories frequently precede observation in physics. And, if observations do not match theoretical expectations, there is trouble. When the number of neutrinos de tected on earth from nuclear reactions in the core of the sun was only about a third of what had been calculated, that resulted in "the mystery of the missing solar neutri nos". Neutrinos had always been thought to have a mass of precisely 0, and the mys tery could only be resolved by assuming that not all of the three forms of neutrino had a mass of 0. Apparently, at least one, and may be all three, could change in type. And, if that were so they knew time and, consequently, had a mass different from 0. In the social sciences, theories are not that precise. Most commonly their nature is that of a concept, or of an explanatory or analytical framework. But as such they fulfil the same function as theories in physics, and in the natural sciences more generally. Two British science writers, Ian Stewart and Jack Cohen, had the following to say about the subtle role of theories in their 1997 book entitled Figments of Reality. "Everyone accepts that theories provide explanations of observed 'facts' by fitting them into a coherent conceptual framework. The true role of theories, however, lies rather deeper: without a theoretical framework, the meaning of observations may not be clear." I find that very well put and quote it with full approval.