Universidade Fernando Pessoa
Porto, Portugal
Basic Principles in Foredeep & Foldbelt Basins
Without going into epistemological details, which can easily be found on the writings of Hume, Bacon, Kant, Popper, Kuhn etc., two philosophical schools have been fighting for a long time on the origin of knowledge and especially on the origin of scientific knowledge. For the empiricists, like Hume and Bacon, knowledge is the result of induction, i.e. the basis of knowledge is observation. For the rationalists, on the other hand, among which Kant and Popper are the most famous defenders, knowledge is the result of deductive reasoning. Observations are used just to test or to refute the à priori adopted hypotheses (conjectures).
In the inductive approach, petroleum geologists start by making observations. Then, they invoke hypotheses. Their hypotheses can never be completed verified by posterior observations. On the other hand, very rarely do they try to refute them (1). The “scandal” of induction, as it’s come to be known, is that observations are necessarily limited – you can’t keep throwing rocks at windows forever in order to conclude that throwing a rock at a window it breaks. That is, the experimental method is “finistic” (M. Macrone, 1994).
(1) On this subject, the swan metaphor of K. Popper is highly significant. In a slightly modified form, it can be expressed as follows: It is not because a Brazilian geologist saw 2332 cute "métisses" in Copacabana beach, that he has the right to say that all "métisses" in Copacabana are cute (induced hypothesis). Just one less cute "métisse" is enough to refute the induced hypothesis, even if he spends one or two months to find her. Actually, most geologists, just see what interests them, i.e. the cute ones.
In the rationalist or hypothetic-deductive approach, explorationists try to solve problems by trial and error. When they have a problem, they advance à priori hypotheses. Then, they try to refute them by observations. These two scientific approaches are very different:
a) In the inductive approach, a petroleum geologist can to all kind of jobs. He just needs to observe. Observations precede theory (2). In addition, as the continuation of inductive reasoning is the verification of the induced hypothesis, he makes rarely progress. One does not progress seeking to demonstrate that he is right.
(2) If a petroleum geologist does not know what a delta, or a deep sea fan, is, he can spend hours, weeks, even months looking at 3D seismic data, without understanding what he is looking for and what eventually he has mapped. The same is true for explorationists that by challenge, or by unconsciousness, accept tasks for which they have not been trained.
b) In the hypothetic-deductive approach, a petroleum geologist can only do the job for which he was trained. Observations are entirely dependent on the theory adopted by the observer. Theory precedes observation .
In fact, for the rationalists, as K. Popper used to say, there is no such thing as instruction from without the structure, or the passive reception of a flow of information which impresses itself on our senses. All observations are theory-impregnated. There is no pure, disinterested, theory-free observation.
Such philosophic critical thinking strongly contrasts with the inductive thinking of Francis Bacon. Actually, Bacon was rightly worried about the fact that our theories may prejudice our observations. This led him to advise scientists that they should avoid prejudice by purifying their minds of all theories. Similar concepts are still held in several major oil companies. We belong to the geological community that thinks the deductive approach gives the better results in oil exploration. On the other hand, we also think knowledge of Geology began with observations, but we do not say that it derives from observations. Like empiricists, we agree that there are no innate geological ideas, but we also do not believe that all geological knowledge derives from observations.
Explorationists using the inductive approach argue often that geological knowledge is conforms to observations, but as Kant did long time ago, we prefer by far to change the order of the words and to say that all geological observations conform to the geological knowledge of the observer (3).
(3) New hypotheses are indispensable to the profitability and progress of hydrocarbon exploration particularly in mature basins. They are related to hypotheses put forth previously and not to knowledge of the geologist. For a young petroleum geologist, almost all hypotheses can be new. A continuous training of the “knowledge workers” as well as those who manage them, is prime importance (Drucker, P. F., 1993).
