TEN OF THE GREATEST; LIVE FOR LISTS; Philosophical Principles

Article excerpt

Byline: by JULIAN BAGGINI Editor of The Philosopher's Magazine

1 THE HARM PRINCIPLE

by JOHN STUART MILL, 1806-1873

Whenever legislation is proposed that limits our freedoms, someone will reach for Mill's On Liberty and point to the passage that says, 'The sole end for which mankind are warranted, individually or collectively, in interfering with the liberty of action of any of their number, is self-protection. That the only purpose for which power can be rightfully exercised over any member of a civilised community, against his will, is to prevent harm to others. His own good, either physical or moral, is not suf-ficient warrant.' What could be clearer? Except it isn't clear: it depends on what you mean by harm. Does hate speech harm minorities? Does sexist language harm women, by making them less credible in the eyes of society? Philosophical principles are like credit agreements: the headlines are convincing, but the small print catches you out.

2 THE PRINCIPLE OF SUFFICIENT REASON

by GOTTFRIED LEIBNIZ 1646-1716

The idea that everything is as it is for a reason is the assumption behind most of philosophy. If we thought that things just happened, we would not bother to try to work out their causes. But then nor would we assume that longer days meant more sunshine meant warmer weather. But this principle is crucially different from the one that says everything must have a purpose. There must be a reason why the big bang happened, but that does not mean it happened for any end or goal.

3 THE MEAN

by ARISTOTLE, 382BC322BC

Moral thinking is steeped in sharp dualities: Good v Evil, God v Satan, Right v Wrong, Heaven v Hell. Popular mythology, from humanity's fall from grace in the Garden of Eden to Star Wars, is full of tales of people going over to the dark side. But long before modern psychology told us that we all have our shadow side, an Ancient Greek philosopher came up with an idea that was even more subtle: it is not that there are shades of grey between moral black and white - good and bad aren't opposites at all. Rather, the good is a 'mean' that stands between two bads: that of excess and that of deficiency. Courage, for instance, is the mean between the excess of rashness and the deficit of cowardice. Mercy is the mean between the excess of vengefulness and the deficiency of surrender. It's a brilliant idea that utterly transforms how you look at right and wrong.

4 THE FALSIFICATION PRINCIPLE

by KARL POPPER, 1902-1994

Common sense once held that a theory was scientific if you knew how to prove it. But Popper suggested that a theory is only scientific if you know what would disprove it. That's why conspiracy theories are nonsense: no matter what the evidence, believers insist this proves how tough the cover-up is. Similarly, you could argue that the theory that God does what is best for us is not scientific, because whatever happens, believers insist it must be for the greater good. God's goodness may be a theological claim but it's not evidential.

5 OUGHT IMPLIES CAN

by IMMANUEL KANT, 1724-1804

How often do people insist that 'Something should be done' even though they've no idea what that something is? But unless you have an idea what should be done, how do you even know that it's possible to do anything at all? It makes no sense to say something should be unless it actually can be. Kant is usually credited with formulating this principle: 'Since reason commands that such actions should take place,' he wrote, 'it must be possible for them to take place.' In other words, if a prescription is truly rational, then it must be possible. Which means if it looks rational, but isn't possible, it isn't rational at all, like expecting a system to run on debt indefinitely.

6 THE PRINCIPLE OF EVIDENCE

by DAVID HUME, 1771-1776

'A wise man proportions his belief to the evidence' sounds like advice you know already. …