Changes

|Brief=a Scottish philosopher, historian, and essayist; he is widely considered the most important philosopher to write in the English language.|Summary=Hume’s contributions to our understanding of the processes of scientific knowledge change and the nature of scientific change knowledge come from his major philosophical works including ''A Treatise of Human Nature'' (1738) and ''Enquiries concerning Human Understanding'' (1748). He is most noted for his skeptical views on a variety of topics including the powers of human reason, metaphysics, human identity, and the existence of God.[[CiteRef::Fieser (2016)]] He is perhaps best known, first, for rejecting Aristotle’s epistemological distinction between knowledge and belief and replacing it with his own distinction between matters of fact (which depend on the way the world is) and relations of ideas (that are discoverable by thought, such as mathematical truths). This new distinction is known as Hume's Fork. Secondly, he is known for questioning the justifiability of whether knowledge derived from inductive reasoningcan be justified. The problem he posed is known today as Hume's Problem of Induction. [[CiteRef::Morris and Brown (2016)]] Thirdly, Hume questioned whether theological knowledge is possible,and played a substantial role in its removal from the scientific mosaic of the modern world. [[CiteRef::Hyman (2007)]] The impact of these skeptical fallibilist arguments is still felt to this day.|Historical Context=David Hume was born in Edinburgh, Scotland in 1711. His family had a modest estate and was socially connected, but not wealthy.[[CiteRef::Norton (2009)]] They recognized that Hume was precocious, and sent him to Edinburgh University two years early (at the age of 10 or 11) with his older brother (who was 12). He studied Latin and Greek, read widely in history, literature, and ancient and modern philosophy, as well as some mathematics and natural philosophy. [[CiteRef:: Morris and Brown (2016)]][[CiteRef:: Harris (2015)|p. 35-65]] Both at home and at the university, Hume was raised in the stern '''Calvinist faith''', with prayers and sermons as prominent features of his home and university life. [[CiteRef:: Morris and Brown (2016)]] Following the completion of his studies, Hume rejected his family's plan that he become a lawyer, and instead determined to become a scholar and philosopher, engaging in three years of intensive personal study. Living in the aftermath of the acceptance of [[Isaac Newton]]'s(1643-1727) revolutionary theories of motion and gravitation, eighteenth century thinkers proclaimed the ''''Age of Enlightenment'''' and expected philosophy (which then included what we would call the natural and social sciences) to dramatically improve human life. [[CiteRef::Bristow (2017)]] Hume, like many of his times, revered Newton, calling him "the greatest and rarest genius that ever arose for the ornament and instruction of the species". [[CiteRef::DePierris (2006)]]

Although little is known Following the completion of his studies, Humerejected his family's activities during his schooling and afterwards, plan that he would have spent the fourth year of the curriculum at Edinburgh studying natural philosophybecome a lawyer, and would have been exposed instead determined to experimental natural philosophybecome a scholar and philosopher, including Newton's theories. [[CiteRef::Harris (2015)|p. 38-40]] More than thirty engaging in three years earlier, in 1687, Newton had published his ''Philosophiae Naturalis Principia Mathematica'' (''Mathematical Principles of Natural Philosophy'') in which he put forth his '''laws of motion''', '''law of universal gravitation''', and his inductive '''experimental philosophy'''intensive personal study. [[CiteRef:: Westfall (1999)]][[CiteRef::Janiak (2016)]] By about 1700 these theories had become [[Theory Acceptance|accepted]] Living in Britain. [[CiteRef::Barseghyan (2015)|p. 210]] The works of other experimental philosophers were also available to the young Hume. The natural philosophy library at Edinburgh, to which Hume is known to have contributed, contained an extensive collection of the works aftermath of Robert Boyle(1627-1691), the works acceptance of [[Rene Descartes]] (1596-1650), and [[John LockeIsaac Newton]]'s (16321643-17041727) revolutionary theories of motion and gravitation, eighteenth century thinkers proclaimed the ''Essay Concerning Human Understanding''. This work, published in 1689, more than twenty years before Hume was born, propounded Locke's Age of Enlightenment'''empiricist''' view of human knowledge. [[CiteRef::Harris and expected philosophy (2015which then included what we would call the natural and social sciences)|pto dramatically improve human life. 38-40]][[CiteRef::Uzgalis Bristow (20162017)]] Boyle Hume, like many of his times, revered Newton, and Locke were all associated with calling him "the '''Royal Society of London''', which was founded in 1663, almost 50 years before Hume's birth, greatest and sought to promote rarest genius that ever arose for the experimental method ornament and instruction of the new natural philosophyspecies". [[CiteRef::Uzgalis (2016)]][[CiteRef::Rogers DePierris (19822006)]]

By Little is known of Hume's timeactivities during his schooling and afterwards. According to the curriculum then in place at Edinburgh, he would have spent his fourth year studying natural philosophy, and would have been exposed to experimental natural philosophy, including Newton's theories. [[AristotleCiteRef::Harris (2015)|p. 38-40]]More than thirty years earlier, in 1687, Newton had published his ''Philosophiae Naturalis Principia Mathematica''s (384 BC-322 BC''Mathematical Principles of Natural Philosophy'') teleological account of causation had been rejected in favour which he put forth his '''laws of the motion'''corpuscular mechanistic, ''' view law of causation. Derived from ancient atomismuniversal gravitation''', it held that material bodies are made of invisibly small particles, called corpusclesand his inductive '''experimental philosophy'''. The only form of causation is mechanical, by direct physical contact of bodies or their constituent corpuscles[[CiteRef:: Westfall (1999)]][[CiteRef::Janiak (2016)]] By about 1700 these theories had become [[Theory Acceptance|accepted]] in Britain. [[CiteRef::DePierris Barseghyan (20062015)|p. 210]] Natural The works of other experimental philosophers continued were also available to accept Aristotle's distinction between scientific knowledge and beliefthe young Hume. Scientific knowledge was taken The natural philosophy library at Edinburgh, to which Hume is known to be knowledge have contributed, contained an extensive collection of the works of Robert Boyle(1627-1691), the works of causes [[Rene Descartes]] (1596-1650), and consisted of [[John Locke]]'s (1632-1704) ''demonstrationsEssay Concerning Human Understanding'''; proving the necessary connection between cause and effect. This work, published in 1689, more than twenty years before Hume was born, propounded Locke supported this 's '''empiricist''' view of human knowledge . [[CiteRef::Harris (2015)|p. 38-40]][[CiteRef::Uzgalis (2016)]] Boyle, Newton, and made Locke were all associated with the popular notion '''Royal Society of a hypothetical hidden corpuscular microstructure London''', which was founded in 1663, almost 50 years before Hume's birth, and sought to promote the associated notion of a metaphysically necessary connection between cause experimental method and effect central to his system. He nonetheless viewed demonstrative knowledge as seldom attainable because of the unobservability of corpusclesnew natural philosophy. [[CiteRef::DePierris Uzgalis (20062016)]][[CiteRef::Kochiras Rogers (20141982)]]

Although many early eighteenth century thinkers regarded NewtonBy Hume's theories and Locketime, [[Aristotle]]'s empiricism to constitute a unified system, there was a distinct tension between them, which Hume recognized. Newton (384 BC-322 BC) teleological account of causation had been unable to explain his gravitational force rejected in terms favour of a the '''corpuscular mechanismmechanistic''' view of causation. He saw his inductive method as an alternative to the demands Derived from ancient atomism, it held that material bodies are made of a corpuscularism that stood in the way invisibly small particles, called corpuscles. The only form of the acceptance causation is mechanical, by direct physical contact of a mathematically lawful gravitational force on its own termsbodies or their constituent corpuscles. Hume[[CiteRef::DePierris (2006)]] Natural philosophers continued to accept Aristotle's Newton inspired skepticism distinction between scientific knowledge and belief. Scientific knowledge was taken to be knowledge of speculative metaphysical hypotheses led him to reject corpuscularism, causes and his enthusiastic championing consisted of Newton's inductive method led him to challenge ''demonstrations'''; proving the necessary connection between cause and effect. Locke's concept supported this view of causation, knowledge and Aristotle's taxonomy made the popular notion of knowledge a hypothetical hidden corpuscular microstructure and opinion in favour the associated notion of a new epistemic taxonomy metaphysically necessary connection between cause and new concept effect central to his system. He nonetheless recognized that demonstrative knowledge was seldom attainable because of the unobservability of causationcorpuscles. [[CiteRef::Hume DePierris (19752006)]][[CiteRef:: Morris and Brown Kochiras (20162014)]]

By the time he started work on Although many early eighteenth century thinkers regarded Newton's theories and Locke'A Treatise of Human Nature'' at the age of 23s empiricism to constitute a unified system, there was a distinct tension between them, which Hume recognized. Newton had become skeptical been unable to explain his gravitational force in terms of religious beliefa corpuscular mechanism. [[CiteRef:: Morris and Brown (2016)]] The term '''atheism''' was coined by Sir John Cheke almost two hundred years earlier in 1540, to refer He saw his inductive method as an alternative to the demands of a lack of belief corpuscularism that stood in divine providence. The term assumed its modern meaning the way of disbelief in the existence acceptance of God, as divine non-existence emerged as a disquieting possibility in the seventeenth centurymathematically lawful gravitational force on its own terms. [[CiteRef:: Hyman (2007)]] In early modern Christian EuropeHume's Newton inspired skepticism of speculative metaphysical hypotheses led him to reject corpuscularism, theological knowledge was deemed to derive from two sources. and his enthusiastic championing of Newton'''Natural religion''' attempted s inductive method led him to demonstrate Godchallenge Locke's existence and nature through reason, logicconcept of causation, and observation of the natural world. Aristotle'''Revealed religion''' was based on the premise that the text s taxonomy of the Bible was divinely inspired knowledge and thus opinion in favour of a source new epistemic taxonomy and new concept of reliable theological knowledgecausation. [[CiteRef::Fieser Hume (1975)]][[CiteRef::Morris and Brown (20172016)]]

DescartesBy the time he started work on ' rationalism had a proof 'A Treatise of GodHuman Nature''s existence at its foundation, but it was also a challenge to the theological methodology established by Thomas Aquinas (1225-1274), which stressed the limitations age of human reason23, and the need to rely on Biblical revelation. Descartes instead claimed a human capacity to know God and nature through reason alone. However, his rationalist argument for God's existence and guarantorship Hume had become skeptical of the certainty of scientific knowledge was soon rejected as circularreligious belief. [[CiteRef:: Hyman Morris and Brown (20072016)]][[CiteRef::Cottingham (1992)]] It was supplanted by NewtonThe term 's experimental philosophy and Locke's empiricism, both of which stressed experience and observation as sources of the limited knowledge to which humans could aspire, and eschewed metaphysics and speculative hypotheses. [[CiteRef::Rogers (1982)]] Both Newton and Locke were nevertheless devoutly religious, though they held non-standard beliefs. Newton authored an entire volume on Biblical prophesies. [[CiteRef::Mandelbrote (2004)]]Like many natural philosophers associated with the Royal Society, they sought to use the experimental method to demonstrate that the universe exhibited the order and purposefulness of a designed artifact crafted by an all-powerful Intelligence. Hume's atheism''Dialogues on Natural Theology'' was coined by Sir John Cheke (17791514-1557) was a response to such hopesalmost two hundred years earlier in 1540, and was to raise devastating objections refer to thema lack of belief in divine providence. Unlike Locke, Hume saw that empiricism must place God's The term assumed its modern meaning of disbelief in the existence among those speculative questions to be eschewed. [[CiteRef::Hyman (2007)]] Doubts about of God's , as divine non-existence also arose among French intellectuals emerged as a disquieting possibility in the mid-eighteenth seventeenth century, with the first to openly proclaim himself an atheist being Denis Diderot (1713-1784). [[CiteRef:: Hyman (2007)]][[CiteRef::Bristow (2017)]]|Major Contributions=HumeIn early modern Christian Europe, theological knowledge was deemed to derive from two sources. '''s main philosophical contributions were made via several works. The first was Natural religion''A Treatise of Human Nature'attempted to demonstrate God' published in three volumes in 1739 s existence and 1740nature through reason, when Hume was 29 years old. Since it sold poorlylogic, Hume recast and observation of the material into two later publications, natural world. ''Enquiries concerning Human Understanding'Revealed religion', published in 1748, and ''concerning was based on the premise that the Principles text of Morals'' published in 1751. Because the Bible was divinely inspired and thus a source of its controversial nature, Hume had ''Dialogs concerning Natural Religion'' published posthumously in 1779, three years after his deathreliable theological knowledge. [[CiteRef::Morris and Brown Fieser (2016)]][[CiteRef:: Norton (2009)]]

=== Hume and Moral Philosophy ===The basic goal Descartes' rationalism had a proof of God's existence at its foundation, but it was also a challenge to the first three of these works is indicated theological methodology established by Thomas Aquinas (1225-1274), which stressed the subtitle limitations of human reason, and the need to rely on Biblical revelation. Descartes instead claimed a human capacity to know God and nature through reason alone. However, his rationalist argument for God''Treatise''; "an attempt to introduce s existence and guarantorship of the experimental method into moral subjects"certainty of scientific knowledge was soon rejected as circular. [[CiteRef::Morris and Brown Hyman (2007)]][[CiteRef::Cottingham (20161992)|p.7]] Hume sought to extend It was supplanted by Newton's experimental philosophy from natural philosophy into what was then called '''moral philosophy''and Locke's empiricism, both of which he defined stressed experience and observation as sources of the "science of human nature"limited knowledge to which humans could aspire, and eschewed metaphysics and speculative hypotheses. [[CiteRef::Morris and Brown Rogers (20161982)|p.8]] The field of moral philosophy was much broader then than today, Both Newton and included topics that we might classify as psychology or cognitive scienceLocke were nevertheless devoutly religious, as well as epistemologythough they held non-standard beliefs. To Hume, Newton authored an understanding of entire volume on Biblical prophesies. [[CiteRef::Mandelbrote (2004)]] Like many natural philosophers associated with the workings Royal Society, they supported a form of natural religion that sought to use the mind was experimental method to demonstrate that the key to establishing universe exhibited the foundations order and purposefulness of a designed artifact crafted by an all other -powerful Intelligence. Hume doubted both revealed religion and natural religion as sources of knowledge, including "Mathematicsand published strong arguments against both. Unlike Locke, Natural Philosophy, and Natural Religion"Hume saw that empiricism must place God's existence among those speculative questions to be eschewed. [[CiteRef:: Norton Hyman (20092007)|p. 34]] Natural philosophersDoubts about God's existence also arose among French intellectuals in the mid-eighteenth century, like Newton and Boyle, he maintains, had cured themselves of their "passion for hypotheses and systems"with the first to openly proclaim himself an atheist being Denis Diderot (1713-1784). [[CiteRef:: Morris and Brown Hyman (20162007)|p. 8-9]] Hume sought to work the same cure for moral philosophy, which he saw as full of speculative metaphysical hypotheses and constant dispute. [[CiteRef::Morris and Brown Bristow (20162017)]] He proposed an empiricist alternative to ''|Major Contributions=Hume was one of a priorinumber of eighteenth century British philosophers whose work was inspired primarily by Newton'' metaphysics s physical theories and its speculative belief systemsexperimental philosophy. He was a naturalist who rejected any appeal to Hume and Colin MacLaurin (1698-1746) believed that the supernatural mind's operations could be studied by broadly Newtonian observational methods, and in explanations both cases this led them to forms of human naturelocal skepticism. For such beliefs, Joseph Priestly (1733-1804) and because he argued that we cannot justify many David Hartley (1705-1757) applied Newtonianism to both the operations of our beliefsthe mind and to its substance, he is noted as becoming materialists. George Turnbull (1698-1748) and his pupil Thomas Reid(1710-1796) sought to ground Newtonian empiricism in a skeptic. But he also observed that we have noncommon-rational faculties which compel certain sorts sense understanding of beliefs (such as the belief that there is a world external to my mind of which my senses provide knowledge), and it is these faculties of which he wishes to give a positive descriptive accountthus avoiding Hume's skepticism. [[CiteRef::Biro Nichols and Yaffe (20092016)]]

Hume sought 's main philosophical contributions to matters relevant to found an empirical science scientific change were made via several works. The first was ''A Treatise of the mindHuman Nature'' published in three volumes in 1739 and 1740, based on experience and observationwhen Hume was 29 years old. He noted that the application of Since it sold poorly, Hume recast the experimental method to "moral subjects" necessarily differed from its use in natural philosophymaterial into two later publications, because it was impossible to conduct experiments "purposely''Enquiries concerning Human Understanding'', with premeditation". Insteadpublished in 1748, knowledge would be gained "from cautious observation and ''concerning the Principles of human life...by menMorals''s behaviour published in company1751. Because of its controversial nature, Hume had ''Dialogs concerning Natural Religion'' published posthumously in affairs1779, three years after his death. [[CiteRef::Morris and in pleasures". Brown (2016)]][[CiteRef::Biro Norton (2009)]] Here we first consider Hume's views on the mind, which are critical to understanding his views regarding scientific methodology and change. We then consider three issues of central importance to [[Scientific Change|p. 42scientific change]] Experimental psychology in , types of knowledge, the modern sensestatus of inductive knowledge, with controlled experiments in and the laboratory, would not make its appearance until status of theological knowledge within the late 19th century. [[CiteRef::Leary (1979)Scientific Mosaic|scientific mosaic]].

By === Hume and The Science of Human Nature ===The basic goal of the time first three of Hume started work on his 's major works is indicated by the subtitle of the ''Treatise'' the notion that ; "an idea was the primary sort of mental content dominated European philosophy, due, in part, attempt to introduce the works of Descartes experimental method into moral subjects". [[CiteRef::Morris and LockeBrown (2016)|p. 7]] Hume instead used the term sought to extend Newton's experimental philosophy from natural philosophy into what was then called '''perceptionsmoral philosophy'''' to designate mental content , which he defined as the "science of any sorthuman nature". [[CiteRef::Morris and Brown (2016)|p. He supposed there are two sorts 8]] The field of perceptionsmoral philosophy was much broader then than today, '''impressions''' and '''ideas''', which was a new distinction. Impressions include feelings included topics that we get from our senses, such might classify as of a red tomato currently in front of mepsychology or cognitive science, as well as desires, emotions, passions, and sentiments, such as my current hunger for the tomatoepistemology. To Hume distinguished impressions from ideas by their degree of vivacity or force. Thus, I have an impression understanding of the tomato that is currently presentworkings of the mind was the key to establishing the foundations of all other knowledge, including "Mathematics, Natural Philosophy, and an idea of a tomato I ate last week. Hume supposed our ideas are faint copies of our impressionsNatural Religion". [[CiteRef::Owen Norton (2009)|p. 34]][[CiteRef::Morris His work in this area was thus critical to his ideas regarding scientific methodology and Brown (2016)]][[CiteRef::Biro (2009)]]scientific change.

Natural philosophers, like Newton and Boyle, Hume maintained, had cured themselves of their "passion for hypotheses and systems". [[CiteRef:: Morris and Brown (2016)|p. 8-9]] He sought to work the same cure for moral philosophy, which he saw as full of speculative metaphysical hypotheses and constant dispute. [[CiteRef::Morris and Brown (2016)]] He proposed an empiricist alternative to ''a priori'' metaphysics based on pure reason and the speculative belief systems to which it led. [[CiteRef::Norton (2009)]] As a naturalist, Hume rejected any appeal to the supernatural in explanations of human nature. For such beliefs, and because he argued that we cannot justify many of our beliefs, he is noted as a skeptic. But Hume himself rejected skepticism. While skepticism can't be defeated by reason, he observed that we have non-rational faculties which compel certain sorts of beliefs (such as the belief that there is a world external to my mind of which my senses provide knowledge). He wrote that "it is fortunate that Nature eventually breaks the force of all skeptical arguments, keeping them from having much influence on our understanding". [[CiteRef::Hume (2017)]] It was these faculties of which he sought to give a positive descriptive account. [[CiteRef::Biro (2009)]][[CiteRef::Wright (2012)]] Hume sought to found an empirical science of the mind, based on experience and observation. He noted that the application of the experimental method to "moral subjects" necessarily differed from its use in natural philosophy, because it was impossible to conduct experiments "purposely, with premeditation" on such matters. Instead, knowledge would be gained "from cautious observation of human life...by men's behaviour in company, in affairs, and in pleasures". [[CiteRef::Biro (2009)|p. 42]] Experimental psychology in the modern sense, with controlled experiments in the laboratory, would not make its appearance until the late 19th century. [[CiteRef::Leary (1979)]] Due in part to the works of Descartes and Locke, the notion that an idea was the primary sort of mental content dominated European philosophy by the time Hume started work on his ''Treatise''. Hume instead used the term ''''perceptions'''' to designate mental content of any sort. He supposed there are two sorts of perceptions, '''impressions''' and '''ideas''', which was a new distinction. Impressions include feelings we get from our senses, such as of a red tomato currently in front of me, as well as desires, emotions, passions, and sentiments, such as my current hunger for the tomato. Hume distinguished impressions from ideas by their degree of vivacity or force. Thus, I have an impression of the tomato that is currently present, and an idea of a tomato I ate last week. Hume supposed our ideas are faint copies of our impressions. [[CiteRef::Owen (2009)]][[CiteRef::Morris and Brown (2016)]][[CiteRef::Biro (2009)]] Noting that there is a regular order to our thoughts, he asserted that the mind has the power to associate ideas. Hume’s concepts about the association of ideas were novel. He posited three associative principles; '''resemblance''' (as when I recognize that the tomato currently before me resembles the one in my garden), '''contiguity''' in time and place (as when I notice that the tomato is on the table to my left) and '''causation''' (as when I notice that bumping the table causes the tomato to tumble to the floor). Hume believed that by thus anatomizing human nature, its laws of operation could be discovered. [[CiteRef::Morris and Brown (2016)]][[CiteRef::Biro (2009)]] [[CiteRef::Owen (2009)]] Hume He argued that the mind could not be an immaterial substance, though he was also critical of materialism. Regarding personal identity, he Hume wrote that “what we call a ''mind'' is nothing but a heap or collection of different perceptions, united together by certain relations, and supos’d, tho’ falslyfalsely, to be endow’d with perfect simplicity and identity”. [[CiteRef::McIntyre (2009) | p. 182]] It was Hume's careful analysis of the mind that led to his insights relevant to scientific methodology.

Hume took Newton’s opposition to demonstrative science much further, questioning the idea of a necessary mechanical connection between cause and effect. “Present "Let an object be presented to a man whose skill of ever so strong natural reason and intelligence are as great as you likeabilities;” " he wrote, “if the "if that object is of a kind that is be entirely new to him, no amount of studying he will not be able, by the most accurate examination of its perceptible sensible qualities will enable him , to discover any of its causes or effects. Adam [the Biblical first man], even if though his reasoning abilities were rational faculties be supposed, at the very first, entirely perfect from the start, couldn’t could not have inferred from the fluidity and transparency of water , that it could drown would suffocate him, or from the light and warmth of fire , that it could burn would consume him. The No object ever discovers, by the qualities of an object that which appear to the senses never reveal , either the causes that , which produced the object it, or the effects that , which will arise from it will have; nor can our reason, unaided unassisted by experience, ever draw any conclusion about inference concerning real existence and matters matter of fact.” " [[CiteRef:: Hume (17481975) |p. 12109-110]] The connection between a cause and its effect was learned by observation and experience, and could not be shown by demonstrative argument. [[CiteRef:: Bell (2009)]][[CiteRef::De Pierris (2006)]][[CiteRef:: Morris and Brown (2016)]] Hume recast Aristotle's distinction between knowledge and opinion as a distinction between '''Relations of ideas''' and '''Matters of fact'''. [[CiteRef::Hume(1784)| p. 11]] Relations of ideas are ''a priori'' truths that are discoverable independent of experience, and can be shown with certainty by demonstration or intuition. Because they must be true in any world, they cannot provide any new information about our own world. Relations of ideas are confined to the formal sciences of mathematics, geometry, and logic. Examples of such statements include 'a square’s sides add up to 360 degrees', '1 + 1 = 2', or, 'all bachelors are unmarried'. Relations of ideas can not be denied as their denial would imply a contradiction in their very definition. [[CiteRef:: Morris and Brown (2016)]][[CiteRef::Hume (1784)| p. 11]] Matters of fact, by contrast, are ''a posteriori'' statements based on knowledge obtained from the world through observation or experience. Examples of such statements include 'the sky is blue', or 'water is odourless'. Note that the contrary of a matter of fact is not something impossible. The claim that ‘the sun will not rise tomorrow’ is just as intelligible as, and no more contradictory than the claim that ‘the sun will rise tomorrow’. The two claims are only distinguishable by observation and experience. [[CiteRef::Morris and Brown (2016)]][[CiteRef::Hume 1784| p. 11]] Unlike relations of ideas, matters of fact do not hold true in all possible worlds and cannot be established by demonstration. They can never be known with certainty.

Having rejected demonstrative knowledge for the natural world, Hume recast Aristotle's distinction between scientific knowledge and opinion as a distinction between '''relations of ideas''' and '''matters of fact'''. [[CiteRef::Hume (1975)| pp. 108-113]] Relations of ideas are ''a priori'' truths that are discoverable independent of experience, and can be shown with certainty by demonstration or intuition. Because they must be true in any world, they cannot provide any new information about our own world. Relations of ideas are confined to the formal sciences of mathematics, geometry, and logic. Examples of such statements include 'a square’s sides add up to 360 degrees', '1 + 1 = 2', or, 'all bachelors are unmarried'. Relations of ideas can not be denied as their denial would imply a contradiction in their very definition. [[CiteRef:: Morris and Brown (2016)]][[CiteRef::Hume (1975)| pp. 108-113]] Matters of fact, by contrast, are ''a posteriori'' statements based on knowledge obtained from the world through observation or experience. Examples of such statements include 'the sky is blue', or 'water is odourless'. Note that the contrary of a matter of fact is not something impossible. The claim that ‘the sun will not rise tomorrow’ is just as intelligible as, and no more contradictory than the claim that ‘the sun will rise tomorrow’. The two claims are only distinguishable by observation and experience. [[CiteRef::Morris and Brown (2016)]][[CiteRef::Hume (1975)| pp. 11]] Unlike relations of ideas, matters of fact do not hold true in all possible worlds and cannot be established by demonstration. They can never be known with certainty. Hume’s new categories of knowledge made it clear that natural philosophy, since it relied on knowledge of matters of fact, could never aspire to the kind of certainty that Aristotle supposed for scientific knowledge, and should be content with the modest sort of knowledge available through Newton’s inductive method. [[CiteRef::De Pierris (2006)]]

1) "•I I have found that such and such an object has alwayshad such and been attended with such an effect..."

•I 2) "I foresee , that other objects , which appear are in appearance, similar , willhave be attended with similar effects." [[CiteRef:: Hume (17481975) |p. 16114]]

• 1) In the past, the future has been like the past.

• 2) Therefore, the future will be like the past.

But this argument itself relies on induction, ; the very mode of argument it seeks to justify. As Hume put it: "According to my account, all arguments about existence are based on the relation of cause and effect; our knowledge of that relation is derived entirely from experience; and in drawing conclusions from experience we assume that the future will be like the past. So if we try to prove this assumption by probable arguments, i.e. arguments regarding existence, we shall obviously be going in a circle, taking for granted the very point that is in question." [[CiteRef::Hume (17482008)| p. 16]] He concluded that "the conclusions we draw from experience are not based on reasoning or on any process of understanding". [[CiteRef:: Hume (17482008) |p. 15]] But induction is necessary for the conclusions that we draw, not only in Newtonian science, but also in our daily lives, which would not be possible without it. Hume concludes that we are compelled to use induction by a powerful natural instinct, or more specifically his principles of association. "All these operations" he wrote, "are species of natural instincts, which no reasoning… is able either to produce or prevent". [[CiteRef::Hume (1975)| p. 46-47]] Humans must, Hume concludes, rely on "the ordinary wisdom of nature", which insures that we form beliefs "by some instinct or mechanical tendency", rather than trusting "the fallacious deductions of our reason". [[CiteRef::Hume (1975) |p. 55]] In keeping with this naturalistic conclusion, Hume devotes an entire section of the ''Enquiry'' to an argument that non-human animals also learn by induction. He writes that "it seems evident that animals, like men, learn many things from experience, and infer that the same outcomes will always follow the same causes". [[CiteRef::Hume (17482008)| p. 53]] Hume’s conclusion was a radical challenge to the central role assigned by rationalists like Descartes and Leibniz to reason in the production of our knowledge, and is seen today as a step towards modern ideas in cognitive science and neuroscience.[[CiteRef::Biro (2009)]]

In the early modern Christian Europe, theology and natural philosophy were not deemed foreign to one another, but rather seen as compatible parts of an integrated [[Scientific Mosaic|mosaic]] of knowledge. [[CiteRef::Barseghyan (2015)|p. 65]] Theological knowledge derived from observations of nature and its supposed design, the supposed divine revelation of the Bible, and supposed miraculous events where God had intervened directly in human affairs. [[CiteRef::Fieser (20172016)]] As a thoroughgoing empiricist, Hume questioned all these sources of knowledge, and rejected theological knowledge as impossible.

In a letter to Henry Home (1696-1782) published in 1737, Hume confessed that he intended to include a skeptical discussion of miracles in his ''Treatise'' but left it out for fear of offending readers. Critics of religion in eighteenth century Europe faced the risk of fine, imprisonment, or worse. [[CiteRef::Fieser (20172016)]] Hume did later publish his critique in the ''Enquiry''in 1748. He wrote that "A wise man...proportions his belief to the evidence" [[CiteRef::Hume (20042008)| p. 56]] and drew the conclusion that "A miracle is a violation of the laws of nature; and because firm and unalterable experience has established these laws, the case against a miracle is- just because it is a miracle- as complete as any argument from experience can possibly be imagined to be....No testimony is sufficient to establish a miracle unless it is of such a kind that its falsehood would be more miraculous than the fact it tries to establish...When anyone tells me that he saw a dead man restored to life, I immediately ask myself whether it is more probable that this person either deceives or has been deceived or that what he reports really has happened...If the falsehood of his testimony would be more miraculous than the event he relates, then he can claim to command my belief or opinion, but not otherwise". [[CiteRef:: Hume (20042008)| p. 58-59]] The claim that a dead man was restored to life is, of course, central to Christian theology.Hume's arguments have gained a relevance beyond theological knowledge, and have been espoused as a [[methodology]] for evaluating other sorts of extraordinary or surprising claims, such as claims of paranormal occurrences or of extraterrestrial intelligence. They are succinctly summarized by the maxim, popularized by the twentieth century astronomer Carl Sagan (1934-1996), that "extraordinary claims demand extraordinary evidence". [[CiteRef::Sagan (1979)| p. 62]][[CiteRef:: Deming (2016)]] In 1757, Hume published an essay entitled ''The Natural History of Religion'' which was the first systematic attempt to explain religious belief solely in terms of what we would call psychological and sociological factors. [[CiteRef::Fieser (2016)]]

Having called revealed religion into question by doubting miraculous events, Hume's most ambitious skeptical attack on the possibility of theological knowledge was turned his attention to natural theology in his ''Dialogues concerning Natural Religion'', which he arranged to have published posthumously because of its inflammatory nature. In it, Hume raised devastating objections to the claim that the universe showed evidence of purposeful design by an Intelligent Creator. This claim was then widely popular among natural philosophers associated with the Royal Society [[CiteRef::Morris and Brown (2016)]] The ''Dialogues'' is written as a conversation between three characters; ''Cleanthes'', a proponent of the design argument, ''Demea'', a mystic, and ''Philo'' , a religious skeptic generally supposed to be Hume's spokesperson. Philo argues that the analogy between the universe and a designed artifact is weak. For example, we experience only one universe and have nothing to compare it to. We recognize human artifacts by contrast with non-artifacts such as rocks. He also notes that we have no experience of the origin of the universe, and that causal inference requires a basis in experienced constant conjunction between two things. For the origin of the universe we have nothing of the sort. ''Demea'' deems ''Cleanthes'' concept of God as cosmic designer to be anthropomorphic and limiting. In a discussion of the human condition, ''Philo'' asks why an infinitely wise, powerful, and good God would permit human suffering. By the end, Hume's characters ' arguments lead the reader to the conclude, with ''Philo'', that God's nature seems inconceivable, incomprehensible, and indefinable and therefore the question of God's existence is rendered meaningless. [[CiteRef::Hume (20152007)]][[CiteRef::Oppy (1996)]][[CiteRef::Morris and Brown (2016)]]|Criticism=Hume's skeptical arguments were troubling to many, and received a good deal of criticism. He was criticized, notably, by a fellow Scottish philosopher of his times; Thomas Reid. [[CiteRef::Fieser (2016)]][[CiteRef::Nichols and Yaffe (2016)]] Reid rejected Hume lamented 's theories of perception and causation because of their skeptical consequences. Hume supposed that our perceptual experience was of impressions in our minds. He also maintained that causal relations do not exist in the work fell "deadborn from world, but are rather posited in our minds when two events are constantly conjoined in experience. Such views, taken together, made it impossible to claim that our perceptual impressions are caused by objects in an external world. This would require that external objects themselves, and our impressions of them be conjoined in our experience, which is obviously impossible. Hume accepted that his belief in an external world was merely a matter of habit, custom, or instinct, and could not be justified. Reid found this unacceptable, and supposed that our perceptual experience was directly of objects in the press"world, just as everyday common sense tells us. He noted that such direct experience was no more mysterious than Hume's supposition that we directly experienced impressions in our mind. [[CiteRef::Morris Nichols and Brown Yaffe (2016)]][[CiteRef::Reid (2007)|ppp. 41-10]] It is howeverDescartes, Locke, Berkeley, today regarded and Hume's supposition that the direct objects of perception were mental entities such as a major ideas, impressions, sensations, or sense data remained widely popular into the twentieth century, [[CiteRef::Hatfield (2004)]] but had been strongly challenged by the beginning of the twenty first century [[CiteRef::Warren (2005)]][[CiteRef::Thompson (2007)]]. By that time though, the relationship between this problem and important workthat of external world skepticism had been substantially reconfigured. [[CiteRef::Clark (2017)]]

Historically, due The German philosopher Immanuel Kant(1724-1824) sought to respond to the threatening nature of Hume’s distinction between relations of ideas Hume's skeptical challenge regarding cause and matters of facteffect, particularly to Newtonian physics, as well as in his problem ''Critique of induction there have been many critics of Hume. One of the Pure Reason'' (1781) and most prominent critics explicitly in his ''Prolegomena to criticize Hume on the account of his distinction between the types of propositions was [[Immanuel Kant]]Any Future Metaphysics'' (1783). Kant criticized sought to synthesize early modern rationalism with empiricism, and thereby avert Hume's skepticism. He did this by supposing that the world as we can experience it, seeking to validate Newton’s propositions about the sensible world which could never be meaningful under Hume’s distinction. Kant theorized that , is structured by the world was interpreted through sensory and intellect and thus there must exist some sort of ''a priori'' synthetic propositionforms of our cognitive faculties.4 The existence of such understanding is thus a proposition would of course result in a proposition that fit both categories prerequisite for experience. Possible human experience thus conforms to certain necessary laws, which we can know through our reason, independently of Hume’s distinctionexperience. Unfortunately, Kant’s For Kant this ''a priori'' synthetic proposition was debunked with structuring framework included Euclidean space and time, and cause and effect. Kant argued that by such means, the arrival idea of probabilistic determinismnecessary causal laws that human reason could know was restored. [[CiteRef::Rohlf (2016)]][[CiteRef::De Pierris and Friedman (2013)]]

As for criticisms on In the twentieth century, Karl Popper (1902-1994) challenged Hume's Problem of Induction, there are skepticism on quite a few casesdifferent grounds. One of the more notable cases was the critique [[Karl Popper]] had towards rejected Hume, stating 's Newtonian inductivism. Popper argued that induction is a mythnever actually used in science, since all observation is selective and theory-laden.[[CiteRef::Popper (1959)]] [[CiteRef::Thornton (2016)]]Popper argued advocated a '''hypothetico-deductive method''' for science, arguing that science is created by conjecture and criticism rather than by reference to the past, and that the main purpose of observations wasn’t to make inferences about the future but to refute present existing theories. Popper was committed to the idea believed that Hume had incorrectly orientated himself towards was mistaken in seeking a means of justifying to justify knowledge. Popper, instead, preferred to look for sought a process by which to reveal and correct errorsscientific error.[[CiteRef::Popper (1963)]]

[[Wesley Salmon]] responded The strongest criticisms directed against Hume were based on his skepticism about theological knowledge. Due to his religious views, he was never able to obtain an academic faculty appointment. His critics called him "The Great Infidel". Hume's arguments in the ''Dialogs'' did not put a stop to this criticism the claim that natural philosophy could find evidence of intelligent design in Hume’s placenature, stating theories still need predictions in part because Hume failed to be testedsupply an adequate alternative explanation for apparently purposeful complexity. When Popperians have multiple theoriesIn 1802, each sharing twenty three years after the same quantity publication of empirical contentHume's ''Dialogues'', William Paley (1743-1805), Popperians would choose an English clergyman, expounded the theories which were better corroborated but lack any justification design argument in this decisionhis ''Natural Theology; or, Evidences of the Existence and Attributes of the Deity''. The Popperians either make Paley argued that the purposeful sophistication of biological "contrivances", such as the eye, were clear evidence of design by an inductive claimIntelligent Being. [[CiteRef::Ayala (2003)]][[CiteRef:: # A theory was reliable in Paley (1809)]] Among those who read and appreciated Paley's arguments were the naturalist Charles Darwin (1809-1882). In his ''Origin of Species'' (1859) Darwin argued that biological species were not separately created and are instead physically descended from pre-existing species, with all living things ultimately descended from a common ancestor. He explained Paley's contrivances by positing the pastprocess of natural selection, which he justified with extensive studies of animal breeding.# It will be reliable By explaining the appearance of design in living systems, Darwin's theory of evolution by natural selection dealt a severe blow to the future having survived falsificationdesign argument among natural scientists.Or they admit corroboration is not an indication Scientists [[Theory Acceptance|accepted]] methodological naturalism, and theological propositions were no longer considered part of predictive powerthe [[Scientific Mosaic|scientific mosaic]].[[CiteRef::Salmon Ruse (1999)]][[CiteRef::Ruse (19672003)]]|Page Status=Needs EditingEditor Approved