Francis Bacon introduced inductivism—and
Isaac Newton soon emulated it—in England of the 17th century. In the 18th century,
David Hume, in Scotland, raised scandal by
philosophical skepticism at inductivism's rationality, whereas
Immanuel Kant, in a German state, deflected
Hume's fork, as it were, to shield Newtonian physics as well as philosophical metaphysics, but in the feat implied that science could at best reflect and predict observations, structured by the mind.
Kant's metaphysics led to
Hegel's metaphysics, which
Karl Marx transposed from
spiritual to
material and others gave it a nationalist reading.
Auguste Comte, in France of the early 19th century, opposing metaphysics, introducing positivism as, in essence, refined inductivism
and a political philosophy. The contemporary urgency of the positivists and of the neopositivists—the logical positivists, emerging in Germany and Vienna in World War I's aftermath, and attenuating into the logical empiricists in America and England after World War II—reflected the sociopolitical climate of their own eras. The philosophers perceived dire threats to society via metaphysical theories, which associated with religious, sociopolitical, and thereby social and military conflicts.
Bacon In 1620 in England,
Francis Bacon's treatise
Novum Organum alleged that
scholasticism's
Aristotelian method of
deductive inference via
syllogistic logic upon traditional categories was impeding society's progress. Admonishing allegedly classic induction for inferring straight from "sense and particulars up to the most general propositions" and then applying the axioms onto new particulars without empirically verifying them, In Bacon's inductivist method, a scientist, until the late 19th century a
natural philosopher, ventures an axiom of modest scope, makes many observations, accepts the axiom if it is confirmed and never disconfirmed, then ventures another axiom only modestly broader, collects many more observations, and accepts that axiom, too, only if it is confirmed, never disconfirmed. Yet ultimately, as applied, Bacon's term
axiom is more similar now to the term
hypothesis than to the term
law. In Bacon's estimation, during this repeating process of modest axiomatization confirmed by extensive and minute observations, axioms expand in scope and deepen in penetrance tightly in accord with all the observations. But, as Bacon provides no clear way to frame axioms, let alone develop principles or theoretical constructs universally true, researchers might observe and collect data endlessly.
Geocentric were both Aristotelian physics and
Ptolemaic astronomy, which latter was a basis of
astrology, a basis of medicine.
Nicolaus Copernicus proposed
heliocentrism, perhaps to better fit astronomy to Aristotelian physics'
fifth element—the universal essence, or quintessence, the aether—whose intrinsic motion, explaining celestial observations, was perpetual, perfect circles. Yet
Johannes Kepler modified Copernican orbits to ellipses soon after
Galileo Galilei's
telescopic observations disputed the Moon's composition by aether, and Galilei's experiments with earthly bodies attacked Aristotelian physics. Galilean principles were subsumed by
René Descartes, whose
Cartesian physics structured his Cartesian
cosmology, modeling heliocentrism and employing
mechanical philosophy. Mechanical philosophy's first principle, stated by Descartes, was
No action at a distance. Yet it was British chemist
Robert Boyle who imparted, here, the term
mechanical philosophy. Boyle sought for chemistry, by way of
corpuscularism—a Cartesian hypothesis that matter is particulate but not necessarily atomic—a mechanical basis and thereby a divorce from
alchemy. In 1666,
Isaac Newton fled London from the
plague. Newton became the exemplar of the modern scientist, and the Newtonian
research program became the modern model of knowledge. Supposedly, Newton maintained that toward his gravitational theory, he had "framed" no hypotheses. For Hume, humans experience sequences of events, not cause and effect, by pieces of sensory data whereby similar experiences might exhibit merely
constant conjunction—
first an event like A, and always an event like B—but there is no revelation of causality to reveal either necessity or impossibility. and interpreted
enumerative induction to be among the mind's unavoidable customs, required in order for one to live. Rather, Hume sought to counter Copernican displacement of humankind from the Universe's center, and to redirect intellectual attention to human nature as the central point of knowledge. Hume proceeded with inductivism not only toward enumerative induction but toward unobservable aspects of nature, too. Not demolishing Newton's theory, Hume placed his own philosophy on par with it, then. Though skeptical at common
metaphysics or
theology, Hume accepted "genuine Theism and Religion" and found a rational person must believe in God to explain the structure of nature and order of the universe. Still, Hume had urged, "When we run over libraries, persuaded of these principles, what havoc must we make? If we take into our hand any volume—of divinity or school metaphysics, for instance—let us ask,
Does it contain any abstract reasoning concerning quantity or number? No.
Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames, for it can contain nothing but
sophistry and illusion".
Kant Awakened from "dogmatic slumber" by Hume's work,
Immanuel Kant sought to explain how
metaphysics is possible. Reasoning that the mind contains categories organizing
sense data into the experiences
substance,
space, and
time, Kant thereby inferred
uniformity of nature, after all, in the form of
a priori knowledge. Kant's
synthetic a priori, then, buttressed both physics—at the time, Newtonian—and
metaphysics, too, but discarded
scientific realism. This realism regards scientific theories as literally true descriptions of the external world. Kant's
transcendental idealism triggered
German idealism, including
G F W Hegel's
absolute idealism.
Positivism Comte In the
French Revolution's aftermath, fearing Western society's ruin again,
Auguste Comte was fed up with
metaphysics. As suggested in 1620 by
Francis Bacon, Human knowledge had evolved from religion to metaphysics to science, explained Comte, which had flowed from mathematics to astronomy to physics to chemistry to biology to
sociology—in that order—describing increasingly intricate domains, all of society's knowledge having become scientific, whereas questions of theology and of
metaphysics remained unanswerable, Comte argued. Comte considered, enumerative induction to be reliable, upon the basis of experience available, and asserted that science's proper use is improving human society, not attaining metaphysical truth. Later, concluding science insufficient for society, however, Comte launched
Religion of Humanity, whose churches, honoring eminent scientists, led worship of humankind. Mill commended Comte's positivism. Mill noted that within the empirical sciences, the
natural sciences had well surpassed the alleged Baconian model, too simplistic, whereas the
human sciences, such ethics and political philosophy, lagged even Baconian scrutiny of immediate experience and enumerative induction. Similarly, economists of the 19th century tended to pose explanations
a priori, and reject disconfirmation by posing circuitous routes of reasoning to maintain their
a priori laws. the five principles whereby causal laws can be discerned to enhance the empirical sciences as, indeed, the inductive sciences. In the 20th, America led. Via the
solar eclipse of May, 29, 1919,
Einstein's gravitational theory, confirmed in its astonishing prediction, apparently overthrew Newton's gravitational theory. This revolution in science was bitterly resisted by many scientists, yet was completed nearing 1930. Not yet dismissed as
pseudoscience,
race science flourished, overtaking medicine and
public health, even in America, with excesses of negative
eugenics. In the 1920s, some philosophers and scientists were appalled by the flaring
nationalism, racism, and bigotry, yet perhaps no less by the countermovements toward
metaphysics,
intuitionism, and
mysticism. mathematics,
logic, and physics, and sought to lend humankind a transparent, universal language competent to vet statements for either logical truth or empirical truth, no more confusion and irrationality. Staking it at the
analytic/synthetic gap, they sought to dissolve confusions by freeing language from "pseudostatements". And appropriating
Ludwig Wittgenstein's
verifiability criterion, many asserted that only statements logically or empirically verifiable are
cognitively meaningful, whereas the rest are merely
emotively meaningful. Further, they presumed a
semantic gulf between
observational terms versus
theoretical terms. Altogether, then, many withheld credence from science's claims about nature's unobservable aspects. Thus rejecting
scientific realism, many embraced
instrumentalism, whereby scientific theory is simply useful to predict human observations, or meaningless. Pursuing both
Bertrand Russell's program of
logical atomism, which aimed to deconstruct language into supposedly elementary parts, and Russell's endeavor of
logicism, which would reduce swaths of mathematics to
symbolic logic, the neopositivists envisioned both
everyday language and mathematics—thus physics, too—sharing a
logical syntax in symbolic logic. To gain cognitive meaningfulness,
theoretical terms would be translated, via
correspondence rules, into
observational terms—thus revealing any theory's actually empirical claims—and then
empirical operations would verify them within the observational structure, related to the theoretical structure through the logical syntax. Thus, a
logical calculus could be operated to objectively verify the theory's
falsity or truth. With this program termed
verificationism, logical positivists battled the
Marburg school's
neoKantianism,
Husserlian phenomenology, and, as their very epitome of philosophical transgression,
Heidegger's "
existential hermeneutics", which
Carnap accused of the most flagrant "pseudostatements". Popper asserted that although exemplary science is not dogmatic, science inevitably relies on "prejudices". Popper accepted Hume's criticism—the
problem of induction—as revealing verification to be impossible. Popper accepted
hypotheticodeductivism, sometimes termed it
deductivism, but restricted it to
denying the consequent, and thereby, refuting
verificationism, reframed it as
falsificationism. As to law or theory, Popper held confirmation of probable truth to be untenable, Logical positivism, Popper asserted, "is defeated by its typically
inductivist prejudice".
Problems Having highlighted Hume's
problem of induction,
John Maynard Keynes posed
logical probability to answer it—but then figured not quite.
Bertrand Russell held Keynes's book
A Treatise on Probability as induction's best examination, and if read with
Jean Nicod's ''Le Probleme logique de l'induction'' as well as
R B Braithwaite's review of that in the October 1925 issue of
Mind, to provide "most of what is known about induction", although the "subject is technical and difficult, involving a good deal of mathematics". Rather than
validate enumerative induction—the futile task of showing it a
deductive inference—some sought simply to
vindicate it. Feigl posed it as a rule, thus neither
a priori nor
a posteriori but
a fortiori. In such mission, Carnap sought to apply probability theory to formalize inductive logic by discovering an algorithm that would reveal "degree of confirmation".
Kurt Gödel's
incompleteness theorem of 1931 made the
logical positivists'
logicism, or reduction of mathematics to logic, doubtful. Some, including logical empiricist
Carl Hempel, argued for its possibility, anyway. ==Early criticism==