Hume - Of the Understanding

David Hume was twelve years old when he went to the University of Edinburgh, and fourteen or fifteen when he left. Before he was twenty the inspiration for A Treatise of Human Nature struck him, and by the time he turned twenty-five it is supposed to have been composed. The Treatise was published in 1739 with the subtitle of An attempt to introduce the experimental method of reasoning into moral subjects. I don't know what you were thinking about when you were a teenager, but I think it safe to say that Hume was something of a philosophical prodigy.

The Treatise is a massive undertaking, and would be for anyone of any age at any time. It is amazing how closely Hume touches the very nature of our understanding and reasoning, and the various operations of the mind. I'm not sure how much justice I could do it, but what the heck. Here is a summary of Book I: Of the understanding. Be warned, this will be lengthy; very lengthy indeed!

Part 1: Ideas

The mind, Hume says, is a bundle of perceptions, and these perceptions are of two kinds: impressions and ideas. An impression is the product of a sense-perception, and ideas follow impressions first as an idea that exactly corresponds to the impression, and then as new ideas which arise from reflection. Consider someone seeing an apple for the first time: the sight of the apple corresponds exactly to the simple idea of an apple, and it will be the colour and shape of that initial fruit. Over time that person will encounter apples of other colours and shapes such that the idea of an apple, though it may still be that first red one, actually represents apples of all the various colours and shapes, if that person stops to think about it. Here Hume is in agreement with his contemporary George Berkeley who said that all general ideas are particular ones that have been annexed to a certain term (what image comes to your mind when I say the word "human"?)

So, from the sight of an object we get a simple idea which exactly corresponds to the object. But imagine then touching and eating that apple: you now have a compounded idea involving not just the idea of an apple, but also the idea of sweetness and smoothness. Upon reflection new ideas may arise, such as, perhaps, the idea of throwing that apple at someone or planting its seeds. Regardless of where your thinking and reflecting take you, the main thing to remember here is that every idea has its origin from some simple impression.

Impressions also involve the "passions" or emotions, such as an assault of anger or a deluge of love, and from those experiences we form very lively ideas of the emotions, and upon reflection we form new ideas about anger or love. But as we think and form ideas the images, or the force and liveliness of the images, become ever more faint compared with the impressions, which enter the mind with the greatest force.

Now, if you think about it, we cannot introduce understanding into the mix until we begin to associate ideas. You understand that an apple is bright red only if you have ideas of other shades of red with which to compare it; you can relate two objects which have no connection to each other through relations such as distance. Hume comes to seven  philosophical relations of this sort:

1. Resemblance: how things resemble each-other is necessary to all philosophical relation, but it is also the greatest source of error - just because one things resembles another does not necessarily mean that the one will behave exactly the same as the other.
2. Identity: this applies to all objects that are constant and unchangeable and which endure. Something which springs into existence and proceeds to change constantly in dramatic and essential ways cannot inspire in anyone the idea of identity.
3. Space and time: under this heading we find distance, contiguity, and terms like above, below, before, after, etc...
4. Quantity: that guy has 5 apples, while I just have this measly one.
5. Quality: or perhaps better said, degrees of quality. Here we have colour, taste, texture, and things of that sort.
6. Contrariety: those two boats are similar, but one has no mast.
7. Cause and effect: this is a very important relation, without which no reasoning would be possible. It is that idea we form from seeing one thing constantly associated with another.

Part 2: of ideas of space and time

Since a simple idea corresponds exactly to a simple impression, we can form no false ideas about that impression; or, as Hume says, the relations, contradictions, and agreements of these ideas are all applicable. You might say, well I could imagine an apple with the shape and colour of a banana, but of course then you are not considering your idea of an apple, but that of a banana. Hume then takes issue with philosophers who discuss notions of the infinite divisibility of space and time. 

When we think of matter we can have a justified idea of a smallest indivisible  part of that matter, or even considering lines, we can have an idea of a mathematical point: but in both cases we can go no further. If you try to imagine dividing a mathematical point you simply end up with the idea of more mathematical points. Since a simple idea corresponds to a simple impression it follows that the impressions of space and time are also not infinitely divisible. It is impossible and contradictory that a finite extension (extension=matter) can have an infinite number of parts, and "whatever appears impossible and contradictory upon comparison of these ideas, must be really impossible and contradictory." It helps nothing to imagine only an infinite number of proportional parts, such as we encounter in Zeno's famous paradox - the contradiction is not resolved. 

The same things applies to time, as each part of time succeeds another, and no two parts can co-exist. Our idea takes us to one indivisible "moment" of time. The moment we start to doubt this is the moment we introduce concepts which have no foundation in experience, and can lead us down the garden path. 

What we must admit to is this: the idea we have in our mind of the infinite is little more than the word itself and represents nothing but its definition. This section was mostly in response to the rationalists like Descartes who supposed that because we have an idea of the infinite, the infinite must exist. The answer is that we do not have any idea of it.

This is not to say that there is definitely nothing in the universe to which the definition of infinite applies, but that without a doubt there is no impression we could ever have of it, and consequently there is not one thing we can say for it outside of its use it math.

"We must in the end rest contented with experience."

Part 3: of knowledge and probability

 

Consider again the 7 types of philosophical relation; these may be further divided into 2 classes: 

1. Those which depend entirely upon the idea.

Consider the relation of equality in a triangle (which may fall under the relation of quantity). The three angles equal two right angles, and this relation is always true and will forever be true, granted that our idea of a triangle does not change. 

2. Those which may be changed without any change in the idea

Relations in space and time, for example. The congruity and distance between two objects may change without any change in the ideas of the objects.

Of these two classes, only those relations which fall under the first can be the objects of certain knowledge. This is because they depend solely on our ideas, and we can make no error in them so long as we hold our ideas constant. The second class, however, deals with place, causation, and identity and none of these relations can offer absolute certainty, as will be shown later. But, to return to the first class...

There are four relations which depend entirely on ideas: resemblance, contrariety, degrees in quality, and quantity or number. The first three are intuitive; that is, we take note of these relations immediately without any further inquiry or reasoning. Proportion in quantity and number, however, is a different story.

Hume calls geometry "the art, by which we fix the proportions of figures." It is an art because geometry draws its first principles from the general appearance of objects, and then fixes the proportions. The perfect figures of geometry are not to found in nature however, so there is a slight defect introduced there when reasoning from geometry to the external world. Algebra and arithmetic suffer no similar defect because they take as their standard number, and there can be no error introduced here (so long as our idea of number does not change.)

So much for certainty, what of the second class of relations mentioned above? Since we can not speak in terms of absolute certainty here, we are therefore reduced to probability. The three relations noted in this class were identity, space and time, and causation. Of the first two, "the mind cannot go beyond what is immediately present to the senses." When comparing the location in time and space and the identity of two objects we are simply perceiving and not reasoning. Nothing in the object could possibly tell us that it is always remote from, or contiguous with, another object. We can only know these things with a degree of probability through experience, and then we find that we are actually discussing cause and effect. What is the "cause" of somethings motion, location, or particular identity?

Causation  

What is the impression which first gives rise to the idea of cause and effect? It cannot be any quality in objects, but must arise from some relation amongst objects. We can note, then, that causes and effects are contiguous: there is a priority in time of cause before effect. But there is more to our idea then this - we think of a cause as necessary. We do not imagine, for example, that there is only a 'chance' that water will freeze when the temperature dips below zero degrees Celsius, we think of it as necessary. However, it is not possible that we can get this idea from pure reasoning - nobody could look at water in one place and feel cold in another, and reason that cold should cause water to freeze - so we must have developed this idea through impressions of observation and experience. But how does this lead us to an idea of necessary cause?

So we start with impressions of the senses and of memory (for if we had no memory we could not remember that one object has always followed another.) From this impression we get an idea, by inference, of contiguity, succession, and constant conjunction. But we are still a long way from anything like a necessary connection; we are still dealing with probability - even if we observe that conjunction a thousand times.

Hume puts the origin of the idea of necessary connection aside here and proceeds to the nature of that idea and of belief in general. You can skip it if you want, but belief certainly does come to bear on the question of necessary causes.

Belief

What is belief? Consider an idea believed in: nothing new is added to the idea through belief. Furthermore, two people could be presented with the same idea, and one believes while the other is incredulous. So what is the difference between belief and incredulity (unwillingness to believe)? The difference must be found in the manner by which we receive the idea rather than the nature of the idea itself. An idea believed in "feels" different than an idea seen as fictitious.

Hume defines belief as "a lively idea related to or associated with a present impression."

What are the causes of belief? From the above definition the answer must lie in the impressions associated with the belief, and also in the relation of ideas. When the mind is presented with an impression, it is transported to ideas which are related to it, and these ideas receive some of the force and "vivacity" of the impression. In what ways are ideas given force and vigor?

Resemblance: For example, when you see a picture of a loved one, the impression is caused by resemblance and the passions associated with it are enlivened. When you are presented with another picture, the force of the former is lessened as its idea competes with that of the new picture. Hume also points to the objects and rituals present in Catholicism as another example. These act similarly, enlivening the ideas associated with them. Consider some object - a staff, a chalice, or robe - that is said to have been used by a saint centuries ago. Just by being in the presence of the object, the believer's related ideas are all enlivened.

Contiguity: A good example of this would be to consider what happens as you near home at the end of a long trip. Like, when I drove from Victoria to St. John's a few years ago. My idea of home was faint and easily forgotten as I traveled through scenery and cities where I had never been before. My mind was turned towards these things. When I boarded the ferry in Nova Scotia that idea of home began to come to life, and with every passing landmark the liveliness of that idea increased: as when I saw the coast emerge through the shrouds of fog, or passed by Marble Mountain, and finally as I crossed the isthmus connecting the main of the island to the Avalon. Perhaps a similar phenomenon can be said to happen when pilgrims visit mecca or the Holy Land. There is a contiguity in the mind between that place and all the events that are supposed to have occurred there which immediately comes to bear on the belief.

Custom: Custom proceeds from past repetition and operates before we have time for reflection. Culture and education could probably go here.


The influence of belief

Of the passions, admiration, shock, or surprise can cause a more easy belief. This is why individuals who make extravagant claims and "magnificent pretensions" often invite an easy faith from other people who are credulous. (credulity - "a too easy belief in the testimony of others.")

Of the imagination, belief causes a more easy reception of extraordinary events. This is why writers try to make the surrounding events in their stories as true and believable as possible. We see this a lot these days where "gritty" and realistic fantasies are so popular. The Game of Thrones, for example - though it contains many impossible things - somehow still feels believable. Also, think of the new wave of superhero movies, dark and realistic and fully explained in the light of science (explained at least for the purposes of the movie.)

As the Cardinal de Retz said, "there are many things, in which the world wishes to be deceived."

But, enough of that, lets get back to the idea of necessary connection:

Of the idea of necessary connection


Again, what impression gives rise to the idea of necessity, considering that every idea begins as an impression? Simply seeing two objects in conjunction is not enough to inspire any new idea about those objects, but after repeated observations, "upon the appearance of one of the objects, the mind is determined by custom to consider its usual attendant." It is this determination that is the impression we are looking for; that is, from seeing that one object always follows another we reflect and form the idea of cause and effect, and this creates a new impression: "an internal impression of the mind, or a determination to carry our thoughts from one object to another." And this is exactly as far as we can go when considering the necessity of causes and effects.

All this is not to say that the objects we observe don't actually have some hidden "power" by which they are able to produce an effect, but we should not think that our idea of this is adequate. At first I thought that maybe Hume's thesis is outdated; that surely modern science can answer the question of "why" one thing produces an effect, or "how" is produces it. But if you think about it, all we have done is to remove the question to a more minute scale.

Consider a pool table. Before having any experience of moving bodies it is not possible to judge what will happen when two balls impact each other. The idea of the two of them simply coming to rest, or even of the one annihilating the other is just as possible as the idea of both of them moving in different directions after impact. But even after we perform observations and learn of trajectories and energy transfer, we can no more explain why one ball causes the other move than we could the first time we saw it. 

Why is there a transfer of energy? What causes that? Why do particles, such as quarks, have the mass and spin that they have? For all our progress since Hume's day we still are only observing and accumulating experiments, and these certainly do strongly indicate unchangeable and permanent laws of nature, but no amount of observation will ever give us any new ideas about the objects we observe and the "secret power" by which they produce effects. And even that is beside the point, which is that we can form no idea of cause at all without experience.

This brings us to Hume's definition of cause: "an object precedent and contiguous to another, and so united with it, that the idea of the one determines the mind to form the idea of the other." (emphasis added by me)

Because causation is an idea that exists in the mind, "anything may produce anything." This is not to say that everything may be the real cause of anything, but since cause is determined  in the mind anything may be perceived to produce anything. For example, when playing poker, sometimes there are all-in scenarios where you have the best hand but your opponent has several "outs" by which he or she could win the hand. The mind immediately dwells on those outs, almost expecting them, and if your opponent hits one of those outs on several occasions you being to feel that you and your thoughts are somehow the cause of that outcome. From this mistaken idea of causation you may then form any number of new superstitions, such as walking away from the table, forcing yourself to think of something else, etc...

So Hume gives us some general rules by which to judge of causes and effects:
- The cause and effect must be continuous in space and time
- The cause must be prior to the effect
- There must be a constant union between cause and effect
- The same cause always produces the same effect
- When multiple causes produce the same effect, there must be something common among the causes.
- Anything which exists for a period of time without producing its effect must not be the sole cause of that effect.

For Hume philosophers commit some of the most egregious errors. Upon discovering that there is no known connection between objects, they are not content to conclude that we can have no idea of power or agency, so they torture themselves trying to explain it. The analogy drawn here is to the endless and fruitless task of Sisyphus.

Part IV: of the sceptical and other systems of philosophy

From all this you might expect Hume to be a thorough skeptic, but actually he asserts that a total skepticism is not possible, it is even contradictory, since skeptics of that sort are using reason to attack reason. Reasoning and belief are kinds of sensation or manners of conception, and these cannot be destroyed by ideas and reflection. You could try to hold on to some abstract reasoning to deny the possibility of anything, but the moment you relent, nature takes over and returns you to that state of being where you reason on cause and effect. This is because it isn't easy to form a strong belief based on nothing but abstractions and subtile reasoning, there is no lively idea there informed by any present impression; there is no chalice you could hold in your hand that enlivens a total skepticism!

The last chapter in this book is maybe my favourite. Of all the sections and chapters that outline his philosophy, he admits in the last that he still overwhelmed by uncertainty and doubt - not about the system he has devised, but about the consequences of it. "the memory, senses, and understanding are...all of them founded on the imagination, or the vivacity of our ideas."

"We have, therefore, nothing left but betwixt a false reason and none at all."

But, I think, as does Hume, that there is actually a positive consequence to this system. That is, we should not torture ourselves with unanswerable questions, but live life as we naturally do, by the very reason we live by. Yet, "if we assent to every trivial suggestion of the fancy; beside that these suggestions are often contrary to each other; they lead us into such errors, absurdities, and obscurities, that we must as last become asham'd of our credulity."

Even when we are unable to completely dispel the cloud of uncertainty, "nature herself suffices to that purpose, and cures me of this philosophical melancholy and delirium, either by relaxing this bent of mind, or by some avocation, and lively impression of my senses, which obliterate all these chimera's."

I wish I could quote this chapter in full, but I can't find the text online. So here are a few more quotes:

"If I must be a fool, as all those who reason or believe anything certainly are, my follies shall at least be natural and agreeable. Where I strive against my inclination, I shall have a good reason for my resistance; and will no more be led a wandering into such dreary solitudes, and rough passages, as I have hitherto met with."  Hume, in the progression of these thoughts actually at one point suffered a nervous breakdown. The cure to this was a denial of abstract philosophical thought, and an embrace of friendship, comradeship, and a love of life. That is really the message to be taken home: do not torture yourself with unanswerable questions, but be content with experience.

Anyway, I will leave it there. The next book is entitled "Of the passions", and I am interested to see where he takes that topic.