Editing David Hume (section)

=== Induction and causation<!--linked from 'Problem of induction'--> ===
The cornerstone of Hume's epistemology is the [[problem of induction]]. This may be the area of Hume's thought where his scepticism about human powers of reason is most pronounced.{{sfn| Kenyon|Craig|1985|p=?}} The problem revolves around the plausibility of [[inductive reasoning]], that is, reasoning from the observed behaviour of objects to their behaviour when unobserved. As Hume wrote, induction concerns how things behave when they go "beyond the present testimony of the senses, or the records of our memory".{{sfn|Hume|1777|p=26}} Hume argues that we tend to believe that things behave in a regular manner, meaning that patterns in the behaviour of objects seem to persist into the future, and throughout the unobserved present.{{sfn|Atherton|1999|loc=[https://books.google.com/books?id=9u56iKhWQu4C&dq=hume+Uniformity+of+Nature&pg=PA202 pp. 202–203]}} Hume's argument is that we cannot rationally justify the claim that nature will continue to be uniform, as justification comes in only two varieties—demonstrative reasoning and probable reasoning<ref group="lower-roman">These are Hume's terms. In modern parlance, ''demonstration'' may be termed ''[[deductive reasoning]]'', while ''probability'' may be termed ''[[inductive reasoning]]''.

[[Peter Millican|Millican, Peter]]. 1996. ''[https://web.archive.org/web/20171020020313/http://www.davidhume.org/papers/millican/1996PhD.pdf Hume, Induction and Probability]''. Leeds: [[University of Leeds]]. Archived from the [http://www.davidhume.org/papers/millican/1996PhD.pdf original] on 20 October 2017. Retrieved 6 June 2014.</ref>—and both of these are inadequate. With regard to demonstrative reasoning, Hume argues that the uniformity principle cannot be demonstrated, as it is "consistent and conceivable" that nature might stop being regular.{{sfn|Hume|1777|p=111}} Turning to probable reasoning, Hume argues that we cannot hold that nature will continue to be uniform because it has been in the past. As this is using the very sort of reasoning (induction) that is under question, it would be [[circular reasoning]].{{sfn|Hume|1777|p=115}} Thus, no form of justification will rationally warrant our inductive inferences.

Hume's solution to this problem is to argue that, rather than reason, natural instinct explains the human practice of making inductive inferences. He asserts that "Nature, by an absolute and uncontroulable {{sic}} necessity has determin'd us to judge as well as to breathe and feel." In 1985, and in agreement with Hume, John D. Kenyon writes:{{sfn|Kenyon|Craig|1985|p=254}}

<blockquote>Reason might manage to raise a doubt about the truth of a conclusion of natural inductive inference just for a moment&nbsp;... but the sheer agreeableness of animal faith will protect us from excessive caution and sterile suspension of belief.</blockquote>

Others, such as [[Charles Sanders Peirce]], have demurred from Hume's solution,{{sfn|Harris|2004|loc=[https://books.google.com/books?id=uBbfizzKTDoC&pg=PA42 p. 42]}} while some, such as Kant and [[Karl Popper]], have thought that Hume's analysis has "posed a most fundamental challenge to all human knowledge claims".{{sfn|Popkin|2014}}

The notion of [[Causality|causation]] is closely linked to the problem of induction. According to Hume, we reason inductively by associating constantly conjoined events. It is the mental act of association that is the basis of our concept of causation. At least three interpretations of Hume's theory of causation are represented in the literature:{{sfn|Read|Richman|2002|pp=13–14, 69}}

# the [[Logical positivism|logical positivist]];
# the sceptical realist; and
# the [[Quasi-realism|quasi-realist]].

Hume acknowledged that there are events constantly unfolding, and humanity cannot guarantee that these events are caused by prior events or are independent instances. He opposed the widely accepted theory of causation that 'all events have a specific course or reason'. Therefore, Hume crafted his own theory of causation, formed through his empiricist and sceptic beliefs. He split causation into two realms: "All the objects of human reason or enquiry may naturally be divided into two kinds, to wit, Relations of Ideas, and Matters of Fact."<ref name=":5" /> Relations of Ideas are ''a priori'' and represent universal bonds between ideas that mark the cornerstones of human thought. Matters of Fact are dependent on the observer and experience. They are often not universally held to be true among multiple persons. Hume was an Empiricist, meaning he believed "causes and effects are discoverable not by reason, but by experience".<ref name=":5" /> He goes on to say that, even with the perspective of the past, humanity cannot dictate future events because thoughts of the past are limited, compared to the possibilities for the future. Hume's separation between Matters of Fact and Relations of Ideas is often referred to as "[[Hume's fork]]."<ref name="SEP">Morris, William Edward, and Charlotte R. Brown. 2019 [2001]. "[https://plato.stanford.edu/entries/hume/ David Hume]." ''[[Stanford Encyclopedia of Philosophy]]''. Stanford: Metaphysics Research Lab. Retrieved 18 May 2020.</ref>

Hume explains his theory of causation and causal inference by division into three different parts. In these three branches he explains his ideas and compares and contrasts his views to his predecessors. These branches are the Critical Phase, the Constructive Phase, and Belief.<ref name="Davidhume 1748">"Davidhume.org." Texts – An Enquiry concerning Human Understanding (1748, 1777). Web. 19 March 2017.<!--find direct ref--></ref> In the Critical Phase, Hume denies his predecessors' theories of causation. Next, he uses the Constructive Phase to resolve any doubts the reader may have had while observing the Critical Phase. "Habit or Custom" mends the gaps in reasoning that occur without the human mind even realising it. Associating ideas has become second nature to the human mind. It "makes us expect for the future, a similar train of events with those which have appeared in the past".<ref name=":5" /> However, Hume says that this association cannot be trusted because the span of the human mind to comprehend the past is not necessarily applicable to the wide and distant future. This leads him to the third branch of causal inference, Belief. Belief is what drives the human mind to hold that expectancy of the future is based on past experience. Throughout his explanation of causal inference, Hume is arguing that the future is not certain to be repetition of the past and that the only way to justify induction is through uniformity.

The [[logical positivism|logical positivist]] interpretation is that Hume analyses causal propositions, such as "A causes B", in terms of regularities in perception: "A causes B" is equivalent to "Whenever A-type events happen, B-type ones follow", where "whenever" refers to all possible perceptions.<ref>For this account of Hume's views on causation cf. {{harvtxt|Ayer|1946|pp=40–42}}</ref> In his ''Treatise of Human Nature'', Hume wrote:{{sfn|Hume|1739|p=167}}

<blockquote>Power and necessity…are…qualities of perceptions, not of objects…felt by the soul and not perceiv'd externally in bodies.</blockquote>

This view is rejected by sceptical [[Philosophical realism|realists]], who argue that Hume thought that causation amounts to more than just the regular succession of events.<ref name="CSW" group="lower-roman" /> Hume said that, when two events are causally conjoined, a necessary connection underpins the conjunction:{{sfn|Hume|1739|p=78|ps=, original emphasis}}

<blockquote>Shall we rest contented with these two relations of contiguity and succession, as affording a complete idea of causation? By no means…there is a ''necessary connexion'' to be taken into consideration.</blockquote>

Angela Coventry writes that, for Hume, "there is nothing in any particular instance of cause and effect involving external objects which suggests the idea of power or necessary connection" and "we are ignorant of the powers that operate between objects".{{sfn|Coventry|2006|loc=[https://books.google.com/books?id=gq348MmuojAC&q=%22effect+involving%22 pp. 91–92]}} However, while denying the possibility of knowing the powers between objects, Hume accepted the causal principle, writing: "I never asserted so absurd a proposition as that something could arise without a cause."{{sfn|Hume|2011|p=187}}

It has been argued that, while Hume did not think that causation is reducible to pure regularity, he was not a fully-fledged realist either. [[Simon Blackburn]] calls this a [[quasi-realism|quasi-realist]] reading,{{sfn|Blackburn|1990|p=?}} saying that "Someone talking of cause is voicing a distinct mental set: he is by no means in the same state as someone merely describing regular sequences."<ref>Quoted by {{harvtxt|Dauer|2010|p=97}}</ref> In Hume's words, "nothing is more usual than to apply to external bodies every internal sensation, which they occasion".{{sfn|Hume|1777|p=78, fn 17}}