An Enquiry Concerning Human Understanding

“[I]n every art or profession, even those which most concern life or action, that a spirit of accuracy, however acquired, carries all of them nearer their perfection […]”

Hume remarks on the complexities of genuine philosophy and gives the reason for pursuing such an endeavor. One would pursue philosophy even when it is difficult or complex to achieve ever greater perfection. Every activity worth doing is worth doing well, and perfection is pursued in every industry. In philosophy, Hume wants to be as precise and accurate as possible so as to carry him closer to perfection than ever before.

“It is remarkable concerning the operations of the mind, that, though most intimately present to us, yet, whenever they become the object of reflection, they seem involved in obscurity […]”

Certain complex things make sense when we are not thinking about them, but immediately become unintelligible when we focus on them. For example, everyone understands the concept of time when they aren’t thinking about it, but one would be hard-pressed to give an accurate and illuminating explanation of it.

“The most lively thought is still inferior to the dullest sensation.”

Hume says that sensations are superior to thoughts and ideas, even though people generally think it’s the other way around. People commonly think that ideas are greater because they exist in the mind and can extend infinitely—one can think of anything, anywhere, at any time. Hume compares the sensation of feeling heat with the memory and points out that the tactile experience is far superior. Thoughts and ideas (as memories) are always going to be inferior, he argues.

“But though our thought seems to possess this unbounded liberty, we shall find, upon a nearer examination, that it is really confined within very narrow limits […]”

People commonly believe that thought is limitless: We can imagine anything, think of anything, combine an infinite number of sensory impressions. However, the limitations of thought become clear when we consider the following: Every single thought exists solely because of a previous sensory impression. This impression created the ability to think about it at some later point. All ideas begin with sensation.

“[E]very idea which we examine is copied from a similar impression.”

The ideas present in the mind don’t come from the mind itself. They are also not created from nothing; they have their source in some other thing. For Hume, these things are our impressions. Hume is not an Aristotelian. However, Hume does follow Aristotle in believing that humans acquire knowledge through sensory experiences.

“It is evident, that there is a principle of connexion between the different thoughts or ideas of the mind, and that, in their appearance to the memory or imagination, they introduce each other with a certain degree of method and regularity.”

Much of Hume’s work concerns the connections between realities and concepts. Hume says that when we happen to produce a chain of different thoughts, one after the other, there is always going to be some link between them, no matter how disparate and unlike one another they may appear on the surface.

“This proposition, that causes and effects are discoverable, not by reason, but by experience, will readily be admitted […]”

Hume says that people in general assume that the cause-and-effect relationship is rationally discovered. However, the senses and not the intellect discover this; it is a relation that can only be experienced, not rationally argued.

“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.”

Classically, philosophers had talked about how the effect is always in the cause in some way, and that the cause is always greater than the effect. Hume wants to say that this is not the case; there is no necessary connection between cause and effect, and nothing about an effect could ever tell us that the cause was greater.

“It must certainly be allowed, that nature has kept us at a great distance from all her secrets, and has afforded us only the knowledge of a few superficial qualities of objects […]”

Hume’s work is a precursor to the philosophy of Immanuel Kant. Here, Hume says what Kant will state with more force: There is no way for the human mind to access with depth real objects in the world. Nature only gives a general impression of itself, and human beings are only vaguely aware of the truth of things. The limitations of human knowing prevent us from knowing the world in as satisfactory a way as we would hope.

“I shall allow, if you please, that the one proposition may justly be inferred from the other […] But if you insist, that the inference is made by a chain of reasoning, I desire you to produce that reasoning.”

Human beings infer all kinds of knowledge about the world. Hume points out that this is not done by reason, as it is so commonly supposed. Inference is made by experience; there is no rational, intrinsic, and necessary connection between various propositions. We understand the way they are related through experience and memory, not by reason.

“For wherever the repetition of any particular act or operation produces a propensity to renew the same act or operation, without being impelled by any reasoning or process of the understanding; we always say, that this propensity is the effect of Custom.”

When Hume tries to understand how we experience cause and effect, and the repetitive nature of acts that come in succession, he defers to what he calls custom. Since cause and effect are not discoverable through reason, they must be discoverable by experience. They are understood through custom, something that occurs some way in general but that has no rational basis. It simply is what it is, much like Hume’s perception of the cause/effect relationship.

“[T]he difference between fiction and belief lies in some sentiment or feeling […]”

Hume explores how belief and fiction impact humans subjectively. Things which we are told have no effect on us are called fiction; they are stories or events that hold no sway over the mind or emotions. Those things that do have an emotional impact are what we call beliefs; they hold some power over our mind and will.

“Though there be no such thing as Chance in the world; our ignorance of the real cause of any event has the same influence on the understanding, and begets a like species of belief or opinion.”

Hume says there is no such thing as chance. Due to the materialistic and deterministic nature of the universe, all events can be predicted and mapped out provided we have enough information. Since we do not have that information, certain things will occur for which we have no explanation or manner of understanding. We say that these things happen by chance when what we really mean is that we have no way of predicting them.

“It seems a proposition, which will not admit of much dispute, that all our ideas are nothing but copies of our impressions, or, in other words, that it is impossible for us to think of anything, which we have not antecedently felt, either by our external or internal senses.”

Many think that ideas and thoughts are original, that they spring from the mind, but this is false. Every idea has its source in some sense impression we experience, either from a physical and external source (feeling the cold, hearing music, seeing a tree) or from some interior source (experiencing anger or jealousy). All ideas are just copies; this makes ideas inferior to experience, which is the source for all knowledge.

“But there is nothing in a number of instances, different from every single instance, which is supposed to be exactly similar; except only, that after a repetition of similar instances, the mind is carried by habit […]”

When a single event of impression is experienced, nothing can be gained by way of true knowledge. However, if a series of impressions are all similar, the mind recognizes the similarities. It imagines a connection that links the various experiences together.

“The general observations, treasured up by a course of experience, give us the clue of human nature, and teach us to unravel all its intricacies.”

Those who have more experience are believed more knowledgeable or wise; this is because they have more sensory impressions to draw from to make sense of the world. Someone with a wealth of experience gained by observation of the world over a long and sustained period of time can more accurately gauge human nature.

“Had not objects a regular conjunction with each other, we should never have entertained any notion of cause and effect; and this regular conjunction produces that inference of the understanding, which is the only connexion, that we can have any comprehension of.”

We could be mistaken when we recognize a cause-and-effect relation in any single event. It is only in observing repeated and sustained events, or the existence of two or more objects, that one can infer a connection. After repeated proximate appearances, one makes sense of their conjunction.

“Human actions, therefore, either can have no moral turpitude at all, as proceeding from so good a cause; or if they have any turpitude, they must involve our Creator in the same guilt, while he is acknowledged to be their ultimate cause and author.”

If one must admit God’s activity in the world, Hume reduces the possibilities to one of two extremes. If God is the creator who brings all things into existence, then human action must either be completely devoid of evil since it has its source in an all-good God, or any evil that exists must be attributed to God alone since God is the source of all existence.

“Animals, therefore, are not guided in these inferences by reasoning: Neither are children: Neither are the generality of mankind […]”

Lower animals are distinguished from human beings due to their lack of intellect and will, and thus a lack of any ability to reason. Whatever they are able to do must be due to something other than reason. Since animals can make inferences by taking account of their actions and choices, making inferences is not due to reason. The same can be said of small children, who have not developed the full and proper use of their rational abilities.

“We frequently hesitate concerning the reports of others. We balance the opposite circumstances, which cause any doubt or uncertainty; and when we discover a superiority on any side, we incline to it […]”

People often question external reports of particular events. Our personal experiences are one thing, but others’ experiences are quite another. When we hear someone else’s account, we question whether it is false, considering how the opposite could be the case. If we discover that one side is clearly superior to the other, that is the side to which we incline and judge that it must be so.

“There must, therefore, be a uniform experience against every miraculous event, otherwise the event would not merit that appellation. And as a uniform experience amounts to a proof, there is here a direct and full proof, from the nature of the fact, against the existence of any miracle […]”

We only call something a miracle when it goes against our normal experience or defies our expectations in some grand way. The fact that something is perceived to be miraculous means that it worked in a way contrary to experience. We only know things by our experiences and that the world works a particular way, ruling out the possibility of miracles.

“In destroying a rival system, it likewise destroys the credit of those miracles, on which that system was established […]”

If we were to suppose that some miracle did exist, or that some particular group was privy to miracles, then we would have to admit that contradictory miracles attributed to other religions or philosophies are false. If we were to do this, however—admit that one set of miracles is false or impossible as opposed to a different set—then we would have logically excluded the possibility of all miracles carte blanche.

“If the cause be known only by the effect, we never ought to ascribe to it any qualities, beyond what are precisely requisite to produce the effect […]”

The philosophers in the classical tradition, such as Plato and Aristotle, taught that causes are always greater than their effects—an effect must participate in its cause in some lesser degree, or otherwise it would simply remain a part of the original cause. Hume argues against this. If all we see are the effects of things, then there is nothing that necessitates attributing them to some greater cause. All we experience are our impressions; these impressions are the only things which can be reasonably expected to exist.