Philosophy
Page 11
Consider, for example, the litmus test often taken in high-school physics classes. Each student is given a piece of the same paper and told to place it on their tongue. To some, the paper tastes bitter; to others, it has no taste at all. So, is the paper really bitter or not? Which students are deceived by their senses?
Case study: Locke and political liberalism
For Locke, the thesis that human beings are born blank slates implies that we are born free and equal, a thesis that led him to develop a groundbreaking political theory. Having read the work of Hobbes, Locke was determined to show that social contract theory need not lead to absolute sovereignty.
Like Rousseau, Locke starts with a more optimistic picture of human behaviour in the state of nature. Although we wouldn’t constantly be at one another’s throats without government, in Locke’s view we would have plenty of occasions for disagreement over one thing in particular: property.
What is property? What does someone have a right to claim as their own – and why? This question cuts right to the core of human social relations. It may not occur to us to ask this question when we are accustomed to dealing only with property transference. That is, it seems obvious that, if you own something, and you give it or sell it to me, then I have the right to claim it as my own. But how did you (or whoever transferred it to you) come to own it in the first place? If you are the first to discover a stretch of land, for example, do you have the right to claim it?
Locke argues that we become rightful owners of something by mixing our labour with it. Clearly, you own your own labour. So, if you make a stretch of unclaimed land into a farm, then you can rightfully call that farm your own. This thesis represented a revolutionary departure from divine or royal conceptions of property and continues to provide a model for rightful ownership today.
In Locke’s view, we consent to government only in order to secure an impartial judge to prevent and resolve property disputes. By conceiving of human social relations in terms of innate freedom and equality, Locke became the founding father of political liberalism. His threefold civic formula of ‘life, liberty and property’ influenced the United States Declaration of Independence, which famously guarantees ‘life, liberty, and the pursuit of happiness’.
The same kind of disagreement turns up for so many other sensations. If the five senses give different data to different people, how can they be regarded as a reliable source of knowledge?
Locke sets out to show that the problem of sensory reliability can be solved by distinguishing between two different types of qualities. Primary qualities, which include size (‘extension’), shape (‘figure’), quantity (‘number’) and motion, are objective because they really exist in the objects. Secondary qualities, which include colour, smell, taste and sound, are subjective, because they exist only in our minds.
It may seem surprising at first to hear Locke assert that a sensation like colour doesn’t really exist. On closer examination, however, it seems he may be right. What is the colour yellow? It is a certain wavelength of light reflecting off an object. Because a wavelength of light has a certain size, shape, quantity and extension, it really exists (it is a primary quality in Locke’s terms). The yellowness, however, is just your eye’s interpretation of that wavelength.
It’s the same for sound. Locke’s answer to the famous philosophical question: if a tree falls in the forest and no one is there to hear it, does it make a sound? is ‘no’. A falling tree creates a disturbance in the air (a primary quality) that becomes a sound (a secondary quality) only for those who have ears. The same goes for taste and smell. These secondary qualities are mental interpretations of primary qualities.
Spotlight
A philosophy professor walks in to give his class their final exam. Placing his chair on his desk, he says, ‘Using every applicable thing you've learned in this course, prove to me that this chair DOES NOT EXIST.’ Pencils fly furiously as the students embark on long, complicated novels. One student, however, spends just 30 seconds writing his answer and then turns it in – to the astonishment of his peers. The professor takes one glance at the exam and gives it an A. The student’s answer to the question: ‘What chair?’
Locke asserts that only the subjective aspect of sensation is unreliable. Primary qualities are reliable because they are objectively measurable. For example, with the litmus test, we need simply show that there are molecules of a certain size and shape on the paper. The fact that this primary quality is interpreted as bitter to some and not to others need not concern us at all. Or so Locke thought…
Berkeley’s slippery slope
George Berkeley (1685–1753) was an eighteenth-century Irish bishop who read Locke’s works enthusiastically, wanting to be an empiricist. He found, however, that Locke’s distinction between primary and secondary qualities becomes a slippery slope that leads straight into idealism, the view we met in Chapter 1, according to which the material world around us is not real.
Berkeley discovered that the very same arguments Locke uses to show that secondary qualities are subjective apply in the same way to primary qualities. Therefore all qualities are subjective, and nothing really exists outside the mind!
Now, if it be certain that those original qualities [i.e., primary qualities] are inseparably united with the other sensible qualities [i.e. secondary qualities], and not, even in thought, capable of being abstracted from them, it plainly follows that they exist only in the mind. But I desire any one to reflect and try whether he can, by any abstraction of thought, conceive the extension and motion of a body without all other sensible qualities. For my own part, I see evidently that it is not in my power to frame an idea of a body extended and moving, but I must withal give it some colour or other sensible quality which is acknowledged to exist only in the mind. In short, extension, figure, and motion, abstracted from all other qualities, are inconceivable. Where therefore the other sensible qualities are, there must these be also, to wit, in the mind and nowhere else.
George Berkeley, Of the Principles of Human Knowledge (http://www.marxists.org/reference/subject/philosophy/works/en/berkeley.htm)
Berkeley reasons syllogistically that, if wavelength 570–590 nm is yellow, and yellow is subjective, then wavelength 570–590 nm must be subjective as well.
Berkeley was rather eccentric for a bishop, because he actually came to believe that the world does not exist. He figured it would be much more efficient for God to transmit the idea of the world to our minds without bothering to create matter. (Descartes, in contrast, as we saw in Chapter 5, would regard this as an intolerable deception, of which a benevolent deity would be incapable.)
Philosophers continue to regard Berkeley as an important part of the history of philosophy, not necessarily because they agree with his idealist conclusion, but because he put his finger on a real problem with pure empiricism. Perhaps the only solution is to find a way to combine it with rationalism, as we shall see Kant attempting, in Chapter 9.
Spotlight
Overheard in eighteenth-century Ireland: ‘Did you hear that George Berkeley died? His girlfriend stopped seeing him.’
Key ideas
Idealism: The view that the material world around us is not real
Memory criterion of personal identity: Consciousness of the past makes you the same person as you were then, despite all your physical and mental changes
Political liberalism: A limited conception of government based on liberty and equality
Primary qualities: Objective qualities that really exist in the objects
Problem of personal identity: How does a human being remain the same person throughout their life?
Secondary qualities: Subjective qualities that exist only in our minds
Ship of Theseus thought experiment: If all of a ship’s planks are replaced one by one, does it remain the same ship?
Tabula rasa: Latin for ‘blank slate’; the theory that human beings are born without any innate ideas
Fact-check
/> 1 According to Locke, the sensation of taste is which of the following?
a A primary quality
b A secondary quality
c An objective quality
d A substantial quality
2 Locke thinks that, when we sleep, we are not…
a Persons
b Human beings
c Really existing
d Really alive
3 Which of the following is central to political liberalism?
a Absolute sovereignty
b Idealism
c Memory
d Equality
4 What does it mean to say that Locke’s distinction between primary and secondary qualities is a ‘slippery slope’?
a It is surprisingly hard to understand
b It contains hidden contradictions
c It disguises other, more controversial, claims
d It leads to something Locke did not intend
5 Which of the following raises the problem of personal identity?
a Alzheimer’s disease
b An ‘antique’ clock with new parts
c Tone deafness
d Colour blindness
6 Suppose Joe and Arlene can’t remember making their wedding vows. Which of the following would Locke be most likely to say?
a They’re no longer married because they’re no longer the same persons
b They’re still married because they’re still the same human beings
c They’re no longer married because they’re no longer the same human beings
d They’re still married because they’re still the same persons
7 Which of the following views does Berkeley endorse?
a Empiricism
b Idealism
c Materialism
d Dualism
8 Which of the following would have the most legitimate claim to own a cave at the bottom of the ocean, according to Locke?
a The person who first discovered it
b The country nearest to it
c The people who make it into a tourist attraction
d The people who know most about ocean caves
9 On which of the following grounds does Berkeley argue that primary qualities exist only in the mind?
a They can’t be conceived without secondary qualities
b They are less reliable than secondary qualities
c They are more reliable than secondary qualities
d They are never accompanied by secondary qualities
10 Where does all knowledge come from, according to Locke?
a Experience
b Reason
c Perception
d Ideas
Dig deeper
Nicholas Jolley, Locke: His Philosophical Thought (Oxford University Press, 1999)
Galen Strawson, Locke on Personal Identity (Princeton University Press, 2011)
William Uzgalis, Locke's Essay Concerning Human Understanding: A Reader's Guide (Continuum, 2007)
8
Hume and causality
‘A wise man proportions his belief to the evidence.’
David Hume
In this chapter you will learn:
• about the problem of induction
• why Hume questions the laws of nature
• the connection between repetition and causation
• why Hume thinks empiricism requires scepticism
• how Leibniz and Spinoza use theism to secure the laws of nature
• Hume’s distinction between logical truths and observed truths
• why Hume rejects miracles as well as the existence of an enduring self.
Thought experiment: miracle pool
It’s Friday night. You’re heading down to your favourite watering hole to have a drink and shoot some pool. When you arrive you note with displeasure that someone you don’t know has already commandeered the pool table. It’s a large man in an odd, reddish hat. He feels your gaze as you pass to the bar and looks up.
‘I’m just getting started,’ he says. ‘Would you like to join me?’
You shrug and nod. Drinks are bought, introductions are made, and the balls are racked.
He breaks and it’s an open table.
‘The three in that corner,’ you call, leaning in for an easy shot.
David holds up his hand. ‘What makes you say that?’
You pause and smile uncertainly. Is he making a joke? When he says nothing further, you take your shot.
The cue ball rolls fast up to the three. Upon contact, however, it comes to an instant halt without budging the three at all. The two balls remain at absolute rest.
‘What the hell?’ you complain. ‘Something’s wrong with the table.’ You reach for the cue ball, pick it up and shake it, while sliding your other hand over the green material on the table.
‘Why do you think something’s wrong?’ David asks.
‘Are you kidding me? This ball just defied the laws of physics…’
‘What a strange thing to say,’ David remarks. ‘Inanimate objects aren’t capable of defying or obeying any laws…’ He plucks the cue ball from your hand, placing it back on the table where it had stopped. ‘Nine in the side.’
You stare at him uncomprehendingly. Not only is he completely unconcerned about the behaviour of the cue ball, he has just called an impossible shot.
‘The nine in this pocket?’ you interject.
‘Yes.’
‘But that would be a miracle!’
David wrinkles his brow in amusement and takes his shot. The cue ball rolls to the nine. Then, barely making contact, and without budging the nine, it reverses and rolls back to where it started.
You gape. He shrugs.
You look around, expecting someone to jump out of the shadows and yell ‘April Fool!’ No one does. You peer into your drink and take a whiff, wondering if someone slipped you a hallucinogen.
‘How’d you rig the balls?’ you ask, reaching for the nine. But he blocks your hand.
‘Just take your turn, will you?’
‘Well, fine,’ you mutter. ‘Why not? But I’m not putting any money on this game.’ You scan the table and then point. ‘The seven in that corner.’
You bend low, aiming carefully for a long shot. The cue ball rolls fast up to the seven. Upon contact, the seven stays at absolute rest while the cue ball leaps off the table and flies towards David, smacking into him hard, right between the eyes. He falls backward against some chairs and tumbles noisily to the ground.
People sitting at the bar turn and gasp. The bartender throws down his rag and storms angrily towards you…
That wasn’t supposed to happen
We’ve all made predictions that turned out to be wrong. When this happens, we typically discover some hidden factor, which, if known, would have enabled us to make the right prediction. The world is very predictable.
And it’s a good thing, because we count on it.
Imagine how hard it would be to carry on with your life if you weren’t sure whether the sun would rise tomorrow or whether gravity would hold.
The world behaves in such a predicable way that scientists codify its behaviour in terms of ‘laws’: ‘For every action, there is an equal and opposite reaction’ and so on. You probably learned several of these laws in your school physics lessons and ‘proved’ them using various projectiles. Well, leave it to philosophers to question what everyone else takes for granted as common knowledge.
The notion of a law implies necessity. When we learn the laws of physics we come to believe that objects behave as they do because they have to. Upon closer examination, however, it cannot be denied that there is a gap between the following two statements:
Things always behave this way.
Things have to behave this way.
To see the gap, all you have to do is think of something you always do, such as have a morning cup of coffee. Suppose you have had a cup of coffee every morning for the past 100 years. Does that mean you have to
have a cup of coffee this morning?
Of course not. In fact, human beings behave in surprising ways far more often than do inanimate objects, which is what leads some people to believe in free will, as discussed in Chapter 6. Setting aside the question of free will, the coffee example shows, at least, that repetition is not the same as necessity.
The problem of induction
The Scottish philosopher David Hume (1711–76) was the first to point this out. He made a revolutionary impact on the history of Western civilization with a single assertion:
The future may not be like the past.
On the surface, this assertion seems so obvious. Of course the future could be different! Who expects it to be the same?
But everyone does, including you. You expect the sun to rise, you expect gravity to hold, and you expect the action of every billiard ball to have an equal and opposite reaction.
To show that these expectations are unwarranted, Hume presents a thought experiment about billiard balls, as in the opening of this chapter. Granted that, in the past, every action has met with an equal and opposite reaction, Hume asks: how do you know this will hold in the future? What’s to stop a billiard ball from behaving in a completely new way?
When I see, for instance, a billiard-ball moving in a straight line towards another; even suppose motion in the second ball should by accident be suggested to me, as the result of their contact or impulse; may I not conceive, that a hundred different events might as well follow from that cause? May not both these balls remain at absolute rest? May not the first ball return in a straight line, or leap off from the second in any line or direction? All these suppositions are consistent and conceivable. Why then should we give the preference to one, which is no more consistent or conceivable than the rest? All our reasonings a priori will never be able to show us any foundation for this preference.