Hume's's Enquiry, UC Davis Philosophy 1, G. J. Mattey

Hume's An Enquiry Concerning Human Understanding
UC Davis Philosophy 1
G. J. Mattey

An Enquiry Concerning Human Understanding Philosophy 1 Spring, 2002 G. J. Mattey	British Empiricism John Locke (1632-1704) adopted Descartess new way of ideas Locke rejected innate ideas, claiming that all ideas come from experience He also held that all that can be known on this basis is our own existence, the existence of God, and that of material things we are now sensing George Berkeley (1695-1753) denied the existence of matter altogether
David Hume Born 1711 Scottish Historian of England Popular essayist Worked in diplomacy Denied teaching position due to charges of atheism Died 1776	Hume's Contributions Argued for moderate skepticism in theoretical matters Cause and effect Personal identity Existence and nature of God Tried to base geometry on sensory experience Originated the belief-desire account of human action Proposed an ethical theory based on the feeling of sympathy
Species of Philosophy There have been two prevailing species of philosophy A popular philosophy, which is easy to comprehend and which motivates people to act virtuously An abstruse philosophy, which is difficult and which seeks to understand the principles governing human nature	Reason and Action Profound research is thought to be useless, and it produces uncertainty that leads to melancholy and rejection It cannot be sustained in a social setting Merely acting, while ignorant, is despised The mind needs rest from constant activity The best life is a mixed one "Be a philosopher, but, amid all your philosophy, be still a man"
Metaphysics Metaphysics is accurate and abstract Accuracy is advantageous to art, business, government, law, etc. The study of metaphysics is pleasurable to those with vigorous minds But its obscurity harbors error by giving shelter to superstition This is why metaphysics must be pursued, yet in an easy manner	The Powers of the Mind An investigation of the powers of the mind will show it unsuited for the investigation of remote and abstruse subjects It is satisfying in itself to map the powers of the mind Can we discover the fundamental sources of these powers? Since they have not been discovered yet, it must be hard to find them
The Origin of Ideas Impressions are original, lively thoughts Sensations Emotions Desires Volitions Ideas are less-lively copies of impressions All (or nearly all) ideas are copies of impressions The test for validity of an abstruse philosophical idea is to find the impression of which it is a copy	The Association of Ideas Ideas and impressions occurring in the mind are connected by general principles Even the most disorganized thought has some thread of order in it There are three such principles Resemblance Contiguity Cause and effect
Relations of Ideas and Matters of Fact Mathematical sciences, which are intuitively or demonstratively certain, concern only relations of ideas They are based on mere thinking Other objects of investigation concern matters of fact There is no contradiction in denying them So what evidence do we have of their truth?	Cause and Effect The senses and memory attest to the real existence of things This testimony is extended by reasoning about cause and effect This reasoning moves from a present fact to a remote fact It does so through the presumption of a real causal connection between the facts But how is this connection known to hold?
Cause and Effect Discovered through Experience We do not know a priori what effect will follow from a given cause Only experience allows us to discover the connection, e.g., that bread nourishes Custom conceals this reliance on experience We cannot without experience predict a particular effect Nor can we discover the general relation	Ultimate Causes Unknown The best we should hope for in natural philosophy is to reduce the causes of natural phenomena to a few (gravity, cohesion) These are based on analogy and observation The causes of these causes are beyond our reach Mathematics cannot uncover causes
Causal Reasoning Causal reasoning is based on experience What justifies our use of experience to draw conclusion about matters of fact? We connect sensible qualities with secret powers: bodies with the perceived qualities of bread have the power to nourish us By what reasoning do we extend the power observed in one piece of bread to an unobserved piece? There is no apparent medium to connect the two	The Missing Link There can be no demonstration connecting the observed with the unobserved The opposite can always be conceived So the connection could only be established by probable reasoning about matters of fact All such reasoning is based on similarity What is the medium connecting the similar to the similar?
Begging the Question It might be said that experience is the required medium It could serve as a medium only if the future resembles the past We infer that the future resembles the past only on the basis of experience But this use of experience then requires the premise that the future resembles the past	Is There an Inference At All? We do not know how to support the inference from the observed to the unobserved It may be that there is no inference at all A child learns at once to avoid a hot surface, and no inference seems to be involved
Skepticism Skepticism talks of doubting, suspending judgment, refraining from rash conclusions As such, it does not ally itself with any of the passions, except love of truth For this reason, it is stigmatized as libertine, profane, and irreligious But skepticism about the basis of causal inference does not undermine ordinary reasoning	Custom and Habit The reason we make judgments based on experience and refrain from then when lacking experience is custom or habit This allows us to conjoin things which in themselves are dissimilar, such as weight and solidity Custom is the great guide to human life It always terminates in a present sensation or memory
Belief The difference between belief and fiction is not to be found in the idea itself Instead, it is a feeling found in belief alone It "gives [ideas] more weight and influence, makes them appear of greater importance, enforces them in the mind, and renders them the governing principle of our action"	Mechanisms of Belief Belief is an intense idea of something In the case of the relation of cause and effect, the idea of one thing is intensified in the presence of the idea of another The same holds for resemblance: our idea of a friend is intensified by a picture of him And also for contiguity: my idea of my home is more intense upon my approach Custom accounts for all these phenomena, in harmony with nature
Probability Although there is no chance in the world, our ignorance of causes makes it seem as if there is Our beliefs about chances reflect the intensity of our ideas of each alternative Our ideas of causes vary in intensity with the number of cases If enough cases concur, there is belief	Necessary Connection Mathematics deals with clear concepts, but with complicated inferences Metaphysics deals with obscure concepts, though its inferences are short The most obscure ideas in metaphysics are those of power, force, energy, or necessary connection What impression lies behind them?
Sources of the Idea Ideas of external objects do not reveal necessary connections We experience only the conjunction; the power remains hidden It is thought that experience of our willing a change in ones body reveals a power But this pretension will be exploded	Willing to Move The consequences of our willing can only be determined through experience We do not know how mind and body are connected We lack control over some parts of our body We do not bring about movements directly
Willing Ideas It is also thought that will is the power to produce or control ideas But we lack an impression of this power We do not know how the mind brings about ideas We lack control over some ideas Our control is variable	Occasionalism Nicolas Malebranche and others claimed that only God is a cause, and alleged causes are only occasions for Gods causality This view detracts from Gods power It also has philosophical defects It too-boldly carries us beyond experience We are as ignorant of any causal power in the mind as in bodies
The Origin of the Idea of Power All we discover through experience is conjunction, not connection Do we, then, have no idea of power at all? When there is constant conjunction, we assert that there is a causal connection The only similarity in the conjunction is repetition of similar instances We feel a transition, and this feeling is the impression from which the idea of power is copied	Causality Defined A cause can be defined in terms of the feeling of transition One definition of cause is "an object followed by another and whose appearance always conveys the thought to that other" This transition is explained in terms of custom and habit
Antecedent Skepticism Descartes sought to prevent error and thus doubted what he could By bringing his own faculties under doubt, he prevented any possibility of removing doubt If there were any self-evident starting point for recovery from doubt, its application would involve the faculties in question A more moderate version is useful: to begin with what is self-evident and make only small steps	Consequent Skepticism Some skeptics focus on the actual deficiencies in our mental faculties Sensory illusion is generally cited But it can be corrected through reason A more difficult problem lies in the natural tendency to suppose that the images of the senses are external, independent objects
Doubting the Senses Philosophy shows that the images of the senses are distinct from independent objects At best, they are copies of those objects But the claim of resemblance cannot be justified We do not know the origin of the images And we have no way to compare the two Appeal to God is ruled out So the teachings of nature are incorrect, and those of philosophy lead to skepticism	Primary and Secondary Qualities It can be shown that the claim of resemblance is contrary to reason We cannot abstract extension from color, primary from secondary qualities Secondary qualities depend on the senses and exist in the mind Primary qualities are no different So, primary qualities exist in the mind All that is left is an unknown something
Skepticism About Mathematics Abstract reasoning involving space and time fall prey to paradoxes of the infinite A real line is divided into infinitely many parts, each one of which is infinitely divisible But this itself is paradoxical, because the initial ideas seem clear, so we are skeptical of our skepticism	Pyrrhonism Extreme skepticism would have us doubt all reasoning concerning matters of fact But this Pyrrhonism is overcome by our need to act Nothing of any lasting value results from itit is mere amusement So the skeptic should confine himself to philosophical objections into abstract matters, such as causality
Mitigated Skepticism Most people are dogmatic, as this is the most effective way to bring about action Some skepticism might cure them of this A just reasoner will always entertain some doubt and caution Another form of mitigated skepticism restricts human investigation to what lies in experience (not the supernatural, e.g.)	.

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