Overview

A Treatise of Human Understanding was first published in 1738. Humedividedthebookintothreeparts.Thefirstbookdiscussedthe nature and mechanism of understanding. In it, Hume explores thought, the foundation of belief, and the place of skepticism. The second book focuses on the passions, investigating the mechanism and function of both emotion and free will. The third book is centeredonmorality.Inthissection,Humeexaminestherootsofthe moral impulse and the nature of moral ideas such as justice, obligationsandbenevolence. Hume enters the work with an argument for the validity of empiricism. He begins with the premise thatall knowledge is based uponsenseexperience.Hethendemonstratesthatallcomplexideas areformedfromsimpleideas,andthatallsimpleideasenterintothe consciousnessthroughthevehicleof senseimpressions. Thislineof reasonequatesideaswithexperiencesandsubjectsthembothtothe samemeasuresofverificationandvalidation.

AnotherkeypiecetoHume’sargumentishisdefinitionof“mattersof fact.” Hume describes matters of fact as aspects of understanding thatmustbeexperienced.Reasonandinstinctare,bythisdefinition, unable to provide us with factual validation. This is the foundation that allows Hume to critically examine metaphysical systems and concepts.TheGodconceptandbeliefsrelatedtothesoularebeyond sense experience and verification. Therefore, they are meaningless questions in epistemological terms. We do not have the capacity to evaluatetheinthelightofexperience. Hume next uses the empiricist definition of fact to investigate the nature of the concepts of space, time and mathematics. In essence, wehavenodirectexperienceof space,butratheronlyof objectswe encounter. Noneof theseobjectshasa qualitywhichcanbedefined as space. Similarly, we have no direct experience of time. We only recognize and form impressions of events we experience. Each of these concepts, therefore, is an illusion of reason. We cannot rest uponitifweareseekingsureandcertainknowledge. Hume examines mathematics from the angle of infinite divisibility. He shows that while in mathematical terms there is no limit to the extent to whichweareableto dividenumbers, ata certainpointin the division, the parts become so small that we are unable to

experience them directly. Therefore, the idea of infinite divisibility, extending beyond the realm of experiential knowledge, becomes meaningless in direct terms. Hume shows that this is the case with many mathematical principles. However, though mathematics itself is beyond experience, it is a system that affords consistent and certain knowledge within the realm of logic. Within the realm of mathematics, and disconnected from the need for experience as a form of validation, mathematics does offer the capacity for perfect certainty. Humeintroducesthetoolsof logic whichheemploysin hisanalysis ofthought.Thefirstofthesetoolsisthemicroscope.Themicroscope isHume’snamefortheprocessof breakinganidea intothevarious simple ideas of whichitiscomposed. If any of these simple ideas is still difficult to understand, it is then isolate and the impressions which led to it are reenacted. It is at this point that Hume’s second logical tool comes into play. This tool, the razor, essentially cuts off alltermsorqualitiesthatcannotbeproventoarisefromthesimple components of the whole concept. The razor establishes certain termsasbeyondtheboundsoflogicandthereforemeaningless. Although Hume establishes metaphysical and conceptual terms as logically meaningless, this is not to say that he finds abstract concepts worthless. Hume believes that the human mind naturally forms associations between impressions that are similar in the framework of space or time. He argues that these associations are the foundation of our capacity to form general expectations and principles. They are abstractions from specific instances that allow us to visualize things we have not experienced by association with thingsthatwehave. The final tool of Hume’s logical analysis is the fork, the capacity to divide truths into various kinds. The first level at which this tool is used is the division of truths based on the relation of ideas from those based on fact. Truths based on the relation of ideas are necessary truths; they are proven once and remained proven for all time. Mathematicsisanentiresystembaseduponthesenecessarytruths. Truthsbasedonfactarethosethatconcerntheoutsideworld. They arethe“mattersoffact”whichareexperiencedinexternalreality. Humenextturnshisattentiontothepassions,therealmofemotions and will. In order to properly describe the nature of the passions, Hume first shows the difference between primary and secondary

impressions. He describes primary impressions as those that arise directlyfromsenseexperience.Secondaryimpressions,ontheother hand, arise internally but have their roots in an original sense experience.Theyareanoutgrowthofprimaryimpressions. Hume first classifies passions as secondary impressions and next divides the passions into two categories: direct and indirect. Direct passions include desire, aversion, grief, joy, hope, despair, security, and fear. Indirect passions include pride and humility, envy and generosity, malice and pity, love and hatred. Direct passions arise from an immediate association with pain or pleasure. Indirect passionsaredevelopedinthesamefashion,butrequiretheinclusion of additional qualities in order to be established. Hume then investigatestherootsandobjectsofeachofthesepassions. Hume recognizes the place of reason in understanding by noticing thatmoraldecisionsinfluenceone’sactionswhiledecisionsmadeon the basis of reason alone do not. Therefore, morality is not based uponreason.Furthermore,anyrecognitionofcauseandeffectstems from a belief we hold about the connections between events and objectsweexperience.Inaddition,thisbeliefonlyhasthecapacityto influence our behavior if it connects with a sense of personal interest. Personalinterest isderived, directly orindirectly, fromthe pain or pleasure we can anticipate associated with the experience. Therefore, our reasoning o the connections between things in our experience are not motivating factors. Instead, weare motivated by pleasure and pain. Passions are the driving force in human thought andaction,andtheproperandonlyplaceofreasoninourthoughtis toservethepassions. Using the platform he has thus established, Hume moves into a discussionof morality.Hehasshownthathumanityismotivatedby passions rather than by reason. He has shown, as well, that the passions are the forces in human understanding that move one towardspleasureandawayfrompain.Inextendingintothearenaof morality, he shows that virtue is our impression of actions that will move towards the pleasure side of the scale, which vice is our impressionofactionsthatwillpushustowardspain. Hume stresses that these moral distinctions are impression rather than constructed ideas, and that these impressions arise solely in consideration of human actions and only within the social framework.Animalsareexemptfromamoralconsideration,andour morality is based not only upon how our actions will affect us, but

the impact they will have upon the whole of society. This leads to a discussion of sympathy as the driving force of morality. Hume recognizessympathyasthefoundationofthemoralobligation. Humegoesontoelaboratefurtheruponhisclassificationofmorality asanimpressionarisingfromthepassions.Hedemonstratesthatwe have no direct experience of the moral impulse. Instead, we receive an internal impression when considering an action which we deem tobeimmoral.Thequalityofimmoralityorviceisnotdefinedbyan idea but by an impression. This verifies his placement of morality amongst the aspects of understanding at which we arrive through sentimentratherthanreason.Reasoncanonlyhelpustounderstand morality. It is not the element of understanding that produces the moralimpulse,butratherthatofpassion.