The Principles of Scientific Knowledge



By Fr. Raymond Taouk 



I.  notion of principle



1.    Principle : id ex quo aliquid procedit quocumque modo, that out of which something proceeds.  Some principles are ontological as part of the real world (starting point of a movement; causes of things).  Some are scientific principles (basic propositions which contain implicitly the formal developments of a science).


2.    The scientific principles are universal and undemonstrable propositions, which are the premises of demonstrations.  These propositions are logical principles in so far as they cause the knowledge of the conclusions.  They are real principles (or probably so) in so far as they explain the world causes.


3.    These principles originate from experimental observation and part. truths (basic propositions or protocols) which are not authentic principles.  A principle is a universal affirmation which allows to make deductions in all or in part of the scientific realm.[1]



ii. the types of scientific principles


1.    Common principles

·        common, first and metaphysical principles are the immediate and most certain truths of the properties of being.  E.g. every h. judgment presupposes the pple of non-contradiction (something cannot be and not be at the same time in the same sense).  Such are the principle of causality presupposed for all sc. knowledge; of compared identity (2 things identical to a third are identical) used part. in Maths; of finality; of moral goodness as first practical principle (do good, avoid evil); of the knowledge of truth (it is a principle presupposed for science).

·      Spontaneous knowledge attains these principles with facility, since there are immediately obtained by mental exercise, and naturally retained by the habit of the first principles.  Thus, these are not only certain truths, they are endowed with the greatest certitude, and are the foundation of the certitude of all other universal truths, the denial of which would lead to scepticism.[2] The critical and profound examination of these principles is the object of metaphysics.

·      The common principles are assumed by each demonstrative science in an analogical way, in so far as they are proportionate to it.[3] The secondary principles receive their power from the first.[4]


2.    In theology, the principles are the articles of faith, contained in the sources of Revelation, the dogmas of the Church Magisterium.  Such principles are higher and more certain than the first metaphysical principles, because they are not based on human reason, but on the Wisdom itself of God.  But they are not separate truths, since the denial of the first pples of Mphscs (of capacity of knowing the truth) leads necessarily to the denial of the particular truths of faith.


3.    The proper, second or particular principles, regard the particular sciences. 

·        In General.  They are fundamental theses of a given science, some more general if they embrace the whole science, others less important if they are particular.

·        The pples of the particular sciences are called norms, laws, rules.  An operative principle is a regulation of the human acts as ordered to a determinate end, as the norm expresses what man must do (not what is) to obtain a given end. Norms or laws can be human (cluedo game), divino-natural (by nat. inclination from the Creator), divino-positive (promulgated by God’s revelation).



iii.  Mathematical and logical principles


1.    Maths is a science essentially deductive, starts from formal pples not ncssly real =axioms/postulates

·        Cert. math. pples are the consequence of free ideal constructions and not of induction, thus they are neither true nor false.  The mind can invent definitions (entia rationis) and axioms which use math. constructions (space of n dimensions).   The math. pples are not arbitrary, as they are subject to the law of non-contrad., and they were abstracted from real quantity.  = Maths is not ttly conventional.

·        Some mathematical principles are real, as laws of quantity, obtained by induction, immediately evident, implicit in every math. reasoning.[5]

·        Relation between them.  Although the conventional pples are more numerous and even indefinite, they are founded however on the real principles, object of philosophy.


2.    Symbolic Logic : something similar occurs here, although the logical signs refer only to 2d intentions, and not to qtty.  Formal logical is based on the pple of non-contradiction, law of reality & Logic.


iv.  physical principles


1.    Physical principles are universal affirmations which express certain properties of the sensible things.

·        They deal with real natures, have empirical reference, and can always be verified sensibly. 

·        the physical laws (= phys. principles)  are the active inclination of the material things to a determinate activity, according to their nature.  The phys. laws are active potencies of a purely material being.  They are the universal affirmation of a uniform comportment of nat. phenomena.  They are usually expressed in mathematical equations if they measure quantitative relations of the bodily activity (law of gravity, of mult. proportions of Dalton, etc.), but they can be approximate laws, laws of statistics and thus only probable laws (laws of biological heredity re. sickness).

·      The phys. laws are schematic: don’t take into account other aspects of the nature and of the world.[6]


2.    Truth and hypothesis.  The principles of physics, chemistry, biological sciences are :

·        very often certain truths, sufficiently corroborated by experimentation.  E.g. the molecular and atomic composition of the bodies, the physico-chemical properties of the elements, the structure of the solar system, the pples of gravity, inertia, conservation of energy etc.

·        often dealing with hypothesis, uncertain universal or particular propositions, but which explain sufficiently a series of facts.[7]  This is called the deductive hypothetical method (1º indicate the probable cause of the facts observed; 2º deduce determined effects explained by no other hypoth.). 

·        These physical hypotheses remain always on the physical or physico-math. level, wo ascending to the metaphysical explanations (nature of things, and divine causality). 

·        Here are some criteria of valid hypothetical formulations : coherence w other parts of science; sufficient empirical verification in diverse surroundings, fecundity to explain other phenomena which may be cause of ‘scientific revolutions’ re. past hypotheses, simplicity and universality (few causes explain many effects and no exceptions ad hoc).[8]

·        The scientific theories are the organisation of scientific knowledge from certain initial presupposits (relativity, quantic theory, atomic theory, etc.).   They work both in inductive and deductive way from facts to principles and back to the facts.  In the organised body, there are various levels :

·      singular facts expressed in basic propositions. Laws which explain series of facts.

·      superior principles which explain diverse laws (theory of gravitation of Newton simplifies the laws of Copernic, Kepler and Galileo; maybe used again in Einstein’s theory of relativity).

·      acceptability.  A sctfc theory is refuted by decisive proofs (astronomical theory of Ptolomeus), but the refutation of the pples of the theory does not prove the falsity of all its elements.[9]

·      The theories are not ncssly hypothetical, some are true when their principles are recognised as such.


v.  conclusive historical panorama


1) science in history


1.    Antiquity.  Science was born in Greece mixed with philosophy in  order to find the principles of the changing sensible phenomena. It developed into geometry (Euclides), astronomy (Hyparcus and Ptolomeus), mechanics (Archimedes), medicine (Hypocrates), optic (Heron), Logic (Aristotle).  The pythagorean and platonic philosophy gave much importance to the mathematical interpretation of natural facts.  Aristotle distinguished the different levels of science according to the degrees of immateriality (physics, maths and metaphysics), and showed that inferior sciences resolve into metaphysics, science of ultimate causes.


2.    Middle Ages.  The Christian authors add the supernatural theology to the Greco-Latin patrimony. Human knowledge is ordered to theological wisdom : philosophia ancilla theologiae.  The European universities became the most powerful centres of the medieval scientific studies, re. 1º theology and liberal arts, esp. Logic. In the XIII c., the discovery of the corpus aristotelicum and the Arabs sparkled interest in nat. sciences and maths, esp. Oxford and Paris, which gave birth to modern science. 


3.    Modern Age.  The success of this period is due to the methodical application of experimentation and the mathematical reading of the phenomena. 


·        The great scientists of the 16th  and 17th Century  are not opposed to philosophy or theology but they do not accept the natural philosophy of Ar. replaced by the new physics (considered as philosophy).  Some (Descartes, Gassendi, Bacon) have a mechanist world view and influence science.

·        The 18th Century of the encyclopedists diffuses the ‘scientific ideal’ : the physico-mathematical knowl is the only one valid, and we must get rid of the religious ‘myths’ and philosophical ideas which are too abstract.  It is the rupture between science and faith, science and philosophy.  Kant considers metaphysics as illegitimate, and limits the value of scientific knowl. only to physics and maths.

·        The 19th Century is the period of the classic positivism (Comte, Stuart Mill, Spencer).  Theol & philo. are past, surpassed by the latest, the history of humanity, the positive science which shows the phenomena (not the nature of things), and the constant regular facts expressed in math. formulae.


4.    The contemporaneous age.  It is an age of relativism and scepticism born from the new maths (non-euclidian geometry), and the new physics (theory of relativity, of quanta, fall off of mechanism), classical criticism (Locke, Hume, Kant).  This allows however the scientists to recognise the limits of their scientific knowledge, and of its use (biology, esp. genetics needs set moral laws).

2) modern theories of the value of science (criteriology)


1.    Beginning of 20th Century .

·        Poincaré sees aspects of sciences brought by h. mind (conventionalism of maths, pples of physics).

·        Bergson says that philo. alone gives true knowl, physico-math sc only manipulates the real.

·        Phenomenology (Husserl) and existentialism stress also the poverty of scientific relativity to philo. This led to a positivist study : study of human science, sociology, but this could not found the sctfc realism.

·        W. James held a relativist view of science (pragmatism/instrumentalism : sc = theory of action).

·        Mach of the Vienna Circle founds the empiriocriticism (sc = analysis of sensations in the fight for life)

·        Frege and Russel try to found the math. sciences on Logic.


2.    Middle of 20th Century

·        The Vienna Circle (Wittgenstein) is antimetaphysical : only verifiable propositions are scientific.

·      Scientists opposed this radical view and held the realist view : Planck, Einstein, De Broglie, Schrödinger, Heisenberg.  To affirm that modern physics has abandoned causality is ttly unfounded.  “Wo the belief that we can attain the real w. our theoretical constructions, wo the belief in the internal harmony of our world, there could be no science” (Einstein).



[1]In Mphscs the principle that ‘God is Self-subsistent Being’ leads to many conclusions.  Yet it is not a principle, but a very important truth.

[2]To know such principles speculatively and spontaneously does not mean that man cannot deny them in his theoretical constructions but that he cannot not live by denying them them practically.

[3]In I Anal Post lect.8.

[4]Idem lec. 43.

[5]Comparative identity, ‘the whole is greater that the part’, are principles which correspond exactly to reality.

[6]The law of inertia is expressed imagining that a body moves in the space wo external influence.

[7] “To explain stg, there can be two types of proofs : some prove the thesis sufficiently... Others no, but are limited to show the congruence of a series of effect.  Thus in astronomy, they (the ancients) use the excentrics and epicycles, so that from this hypothesis, they save the appearances of the celestial movements; but this thesis is not sufficiently proved, since these phenomena could be explained with another hypothesis” I 32, 1 ad 2.

[8]Gravity explains many diverse phenomena of terrestrial and celestial mechanics (macro and microcosmos).

[9]In the history of modern physics, we see more a purification than a refutation of the past theories : Einstein purified the mechanical theory of Newton.