Some Core Passages from "An Inquiry Concerning Human Understanding" by David Hume

The core of Hume's argument centers around over emphasizing a deficiency in the human mode of knowing and using it as a critique of being itself. It is true, human knowledge begins in the senses with particular sense data and has to be abstracted into universal concepts by the intellect. What this means is that all human concepts or universals are limited or incomplete by nature. It does not mean that being itself from which we abstracted the universal is deficient. For example, the Medieval Europeans only knew white swans and so maybe thought that the concept of "swan-ness" necessarily included being white. But then someone brought a black swan. This did not mean that all universals were impossible or that being itself rejects universal hylomorphic forms, but rather that their conceptions of swan-ness were simply incomplete and more experience helps us move closer to the objective universal. 

Indeed, how could we even speak of an objective world were it not a world which had some deeper order giving it intelligibility and stability in its patterns. An electron does what an electron does, and a proton, and gravity ... all the time. The intelligibility of the world to the mind requires the world itself to be the intelligible. 

Likewise, Plato's points about the universality of the nature of ideas and thus being qualitatively different from the physical and individual world still holds true. To be a radical empiricist would require the rejection of all intelligibility in the physical world and the mathematical world as well as the metaphysical. 

Hence these types of epistemological stances really boil down two options ... either a metaphysical realist view which brings one to the ascent of an ultimate reality or a wholly self-refuting skepticism. 

It is also clear that Hume sees to equate metaphysics in general with Cartesian metaphysics in that he only sees two possibilities, an a priori based metaphysics or his anti-metaphysical empiricism. 

It is also interesting to note that both Descartes and Hume are equating human certainty with being itself. Being is equivalent to whatever human certainty we can obtain. Thus being is clear and distinct thought or being is unreachable in itself. 

The Source of Factual Reasoning

Hume begins this passage by saying that "all the objects of human reason or enquiry", aka what are traditionally known as the speculative sciences (physics, mathematics, and metaphysics) are actually only two in number. There are only "relations of ideas", i.e. mathematics, and "matters of fact", i.e. the physical world. 

He then says that relations of ideas are those which are 'intuitively or demonstratively certain", such as arithmetic, algebra, and geometry. These mathematical relations are attainable by simple abstract thought without any recourse to the material content of the world. 

"Matters of fact", on the other hand, are obtained only conditionally in that they are never necessary, such that the contradictory matter of fact could not also be true. "That the sun will not rise tomorrow is no less intelligible a proposition, and implies no more contradiction than the affirmation, that it will rise." 

[It's interesting here that Hume chooses to use the phrase "matters of fact" instead of physical things or material things, which traditionally in philosophy are hylomorphic. Matters of fact seems to reflect a notion in Berkeley, namely that all one can know are the qualities presented to one's senses right now.]

Thus, we can inquire here whether there is anything metaphysical about reality which goes beyond the five senses and the brain's memory. "...to enquire what is the nature of that evidence which assures us of any real existence and matter of fact, beyond the present testimony of our senses, or the records of our memory." [Now he then says that these questions haven't been much addressed in the history of philosophy ... which only goes to show Hume's lack of knowledge on the subject, in my opinion.] 

Hume then says that we have a natural faith in reality which is actually mistaken and true philosophy will correct this. (212) 

Hume then makes a claim: "all reasonings concerning matter of fact seem to be founded on the relation of cause and effect." In other words, any knowledge of the material content of the world relies on us uniting together past, present, and future - both cause and effect. It is this mental union that reason claims to be able to transcend just what the senses provide us right now and those things stored in memory. 

Cause and Effect Based on Experience

How do we arrive at cause and effect? 

Hume, ironically, puts forth a universal truth though he whole argument is aimed at denying universal truths, that there is no a priori knowledge, i.e that there are no innate ideas that allow us to understand cause and effect in the world. 

"I shall venture to affirm, as a general proposition which admits of no exception, that the knowledge of this relation is not, in any instance, attained by reasonings a priori; buy arises entirely from experience, when we find any particular objects are constantly conjoined with each other." 

He claims that there is no object of knowing regarding the qualities relating to the senses that tells us the causes of a thing or its effects, i.e. we are not presented with the things past or its future, but only with its present. 

"nor can our reason, unassisted by experience ever draw any inference concerning real existence and matter of fact." 

His example of Adam here is like Berkeley's example of the blind man being present with a statue of Caesar the first time they can see. The core of what he is claiming is that it is our memory which supplies cause and effect and turns things into substances. 

[Berkeley makes a subtle jab by saying: "... we must be conscious of the utter inability, which we then lay under, of foretelling what would arise from them." Lay under must be a reference to the "stand under" of substance.] (213) 

Hume doubles down on this with the billiard ball example; that if we were created in front of a billiard table we could not know about the transfer of energy that would happen by hitting the cue ball at the stack. Nor if we held up a piece of metal that it would fall and not rise. "The mind can never possibly find the effect in the supposed cause, by the most accurate scrutiny and examination. For the effect is totally different from the cause, and consequently can never be discovered in it."  In other words, we cannot a priori know what effect will result from a thing. (214) 

Hume then makes a jump here from this opening point to something deeper. [And ironically he, again, states this as a universal truth ... in his attempt to deny universal truths.] He says that no sane philosopher ever has made a claim regarding ultimate causes for anything experienced in the world. Rather, through observation, experience, and analogy there are some scientific patterns that can emerge, but the cause of these patterns is a place where the mind just cannot go. In other words, he is rejecting the traditional method of the proofs for God's existence by categorically eliminating metaphysics at the start and therefore claiming we cannot enter any metaphysical explanation and thus must stay at physical causes. 

"Hence we may discover the reason why no philosopher, who is rational and modest, has ever pretended to assign the ultimate cause of any natural operation, or to show distinctly the action of that power, which produces any single effect in the universe. It is confessed, that the utmost effort of human reason is to reduce the principles, productive of natural phenomena, to a greater simplicity, and to resolve the many particular effects into a few general causes, by means of reasonings from analogy, experience, and observation. But as to the causes of these general causes, we should in vain attempt their discovery; nor shall we ever be able to satisfy ourselves, by any particular explication of them. These ultimate springs and principles are totally shut up from human curiosity and enquiry." (215)

Summary So Far

In the next paragraph, Hume says that science helps to reduce our ignorance of the world by these feeble attempts at patterns in understanding, but we can go no further. Philosophy, like metaphysics, only points to a hole or gap in human knowing and leads to nothing. 

To summarize what he has established so far, Hume then boils it down to this. What we know are matters of fact and relations of ideas. Matters of fact are known through cause and effect. Cause and effect is known through experience. Experience, though, brings a greater problem. What does experience rely on? 

The Problem Of Induction

Here Hume tries to make the point that we can have no inherent reasons as to why we connect sensible realities and their effects. He uses the example of bread and says there is no reason why we should connect bread to our health other than that is what we observe. "Our senses inform us of the color, weight, and consistence of bread; but neither sense nor reason can ever inform us of those qualities which fit it for the nourishment and support of a human body." (216) 

And again, "It is allowed on all hands that there is no known connection between the sensible qualities and the secret powers; and consequently, that the mind is not led to form such a conclusion concerning their constant and regular conjunction, by any thing which is knows of their nature." (217) 

He then answers the question above; what is experience based on? It is based on the presumption that the future will be like the past and present. 

Matters of Fact --> Cause and Effect --> Experience --> Assumption that Future will be like past --> Unprovable with reason

"As to past Experience, it can be allowed to give direct and certain information of those precise subjects only, and that precise period of time, which fell under its cognizance: But why this experience should be extended to future times, and to other objects, which for aught we know, may be only in appearance similar; this is the main question on which I would insist." (217) 

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