Hume speaks Of the Origin of Ideas

Hume’s take on the relationship between sensations and ideas is true to his usual style: clear and bold yet careful. His prose leads you step by cautious step up through an argument as though it were the most familiar route ever. Only on occasion does he spin you round and you realise with a jolt how far you’ve climbed; how distant is your starting point.

Section II of Hume’s Enquiry concerning Human Understanding offers no such surprises, although there is an uncharacteristic stumble that Hume seems to assume will go unnoticed. He sets off steadily with the claim that immediate perceptions (impressions) are more vivd than even the most vibrant of ideas; recalling the sensation of pain is nothing compared with having a smouldering cigarette end stabbed into your arm (my example, not Hume’s).

Ideas are nothing but the recollection and recombination of impressions. Our ability to shuffle impressions into combinations other than those in which they were first produced gives us an incredibly advanced faculty of imagination. New worlds are opened up: “the thought can in an instant transport us into the most distant regions of the universe; or even beyond the universe, into the unbounded chaos, where nature is supposed to lie in total confusion.”

The one counterexample Hume considers is dismissed as insignificant. It seems that we are able to form ideas of colour-shades that have not yet been impressed upon us. Having seen only two blue objects – one light blue and one dark blue – we can easily imagine a shade between the two. This also applies – Hume tells us – to pitches of sound, and presumably also to intensities of pain and maybe taste.

In fact Hume doesn’t use the phrase ‘intensities of …’. If he had thought in these terms, he might well have escaped his own counter-example by dividing the simple notion of a ’shade’ into the notion of combined colour and intensity of light. The idea of an unperceived shade is formed by the re-combination of colour-impression and intensity-impression. (As distinct from the idea of an unperceived hue formed by the combination of one colour-sensation and another.)

Interestingly, the earliest use of ‘intensity’ in this sense cited in the OED is attributed to James Hutton in 1794, eighteen years after Hume’s death. Perhaps Hume had in mind the right idea, but science had not yet provided the tools allowing its communication. This might be why he chose to take so little notice of such a stark – if accurate – counterexample.

That our ideas are restricted by past experience is for me the most striking thought. Maybe it should prompt us to rethink how we educate children; how we develop their capacity to entertain abstract concepts. Hands-on learning has for a long time been a buzz-phrase, but Hume gives fresh importance to this style of education. Not only does a broader range of perceptions give us access to more ideas, but a greater experience-base of emotions does too.

The selfish heart, unable to “easily conceive of the heights of friendship and generosity”, will have a hard time coping in a world where others base their relationships on these sentiments. Emotional enlightenment should be given thought along with every other form of education if we are to end up with capable, well-rounded members of society.

Shifting with the sands

What if it’s all a dream? What if my some of my most strongly-held beliefs are based on unreliable evidence? Descartes provides the questions in his First Meditation; here are two possible responses.

One option is to shrug off the scepticism. So what if we can be certain of very little? Certain or not, the beliefs Descartes has us doubt are pretty essential to everyday life; we’re hardly going to ditch them just because of some crazy notion that we may be dreaming. Stop believing you have a body and you might well end up dead. More the stuff of nightmares. Even if this is all a dream, for most of us it’s a damn good one. Let’s just get on with it and leave Descartes to wile away his life in an armchair for fear of entertaining unfounded beliefs.

Sensible as that may be, the second option gives me more comfort. Having read a bit of philosophy, most of us are comfortable to distance ourselves from the unsettling arguments we come across. This works out fine most of the time, but if you’re like me – and Descartes – the shadows are too persistent to be kept constantly at bay. They linger at the back of your mind, clouding forward when there’s space. Idle moments start to fill with niggling thoughts.

The sands may be shifting, but if we’re dreaming we’re shifting with them; from our perspective, they’re flat and solid. They can give us stability relative to their movement; certainty relative to their uncertainty. Dreaming too. When I ask if I have two hands, I’m not asking some deep question involving their existence in four-dimensional space, or whatever. All I want to know is whether there are hands – lumps of flesh and bone with five protrusions – attached to my body; the ‘are’ in the question needn’t have any heavy ontological import. Dream or not, if there are hands attached to what I nomally take to be my body, I’m happy. Believing that there is a desk in front of me just means that I have a bunch of other conditional beliefs, like that if I slam my fist down on top of it, I’ll get hurt while the desk won’t.

Since the belief that we might be dreaming isn’t usually at the forefront of our mind, the content of our other beliefs remains predominantly unaffected. Our belief that there’s a fire in the grate can be true even if we are dreaming it; all we standardly mean by our belief is that there’s something burning over there in that metal enclosure. It’s only when we begin considering the possibility that we’re dreaming that the very meaning of our belief alters. ‘Is’ starts to get all deep on us.

So long as we keep shifting with the sands, there is no obstacle to stability. We can have much more faith in our beliefs than Descartes supposes, since the majority of these beliefs are nothing more than claims relative to whatever situation God might have thrust us into. Only when we start to worry that the sand we’re on might be shifting do the claims stop being relative to our position and start being relative to another, hypothesised yet inaccessible vantage point. If you want certainty, shift with the sands and the rest will follow.