© Copyright - Daniel Courgeau - 2006 - 2012 - All rights reserved - Made by SCENARIO ORIGINAL
The specific or scientific object of a discipline does not initially have an explicit definition. Sciences such as physics and biology, for example, evolve as a series of
successive explanations of their object, as illustrated by the transition from Newtonian physics to Einstein's general theory of relativity. In the same way, the object of
social sciences is made clear through successive paradigms, which describe the various types of relationships between the phenomena observed and the scientific
object.
With the longitudinal paradigm, the aim is to study the occurrence of one single event, during the lifetime of a generation or cohort,
in a population that retains the same characteristics for as long as the phenomenon persists. As with the cross-sectional paradigm,
the population must therefore be considered homogeneous, and the phenomena mutually independent.
The event history paradigm holds that, over the life course, individuals follow a complex trajectory which
depends at any given time on their previous life course and on any information they may have acquired in
the past. The population then becomes heterogeneous, and the phenomena became interdependent. The
following figure, from the same study, shows how under this paradigm, the migration probability of farmers
is significantly lower than for other professions, in contradiction with the cross-sectional model. We will
show that the following paradigm permits to solve this problem.
Finally, the multilevel paradigm goes beyond the opposition between the holism of the cross-sectional or longitudinal
approach and the methodological individualism of the event history approach, for it holds that human behaviour can only
really be understood by bringing different levels of aggregation into play. The following figure, always on the same example,
shows how the variation of the migration probabilities according to the percentage of farmers explains the results.
This shows us first that the event history result is always verified, but that the higher migration probability relates primarily to
non-farmers, since the migration probabilities of farmers are not significantly modified by the percentage of farmers. One of
the hypotheses of the cross-sectional paradigm is no more verified: the probability of migration of the other professions can
no more be considered as independent of their place of residence.
The truth of the following statement by Gilles-Gaston Granger in Formes, opérations, objets (1994) becomes self-evident:
The human fact can indeed be scientifically understood only through multiple angles of vision, but on condition that we
discover the controllable operation which uses these angles to recreate it stereoscopically.
It will be now necessary to go further than these different paradigms in order to give a more axiomatic approach which can
reinforce the scientific pertinence of these sciences. It is first useful to say that the trio fertility, mortality and migration is the
scientific object of these sciences, which is the first step toward what we might call the axiomatization of population
sciences. It would be now necessary to find the basic form of quantitative transformations in any given population that may
set out the general conditions without which the phenomena to be explained would not be what they are. Such an axiomatic
approach would reinforce the scientific pertinence of population sciences.
© Copyright - Daniel Courgeau - 2006 - 2012 - Tous droits réservés - Réalisation SCENARIO ORIGINAL
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