A Lucky Guess

Tara has a geography test. Question 7 asks: "What is the capital of Australia?" She has no idea. She half remembers four city names, closes her eyes, and picks one: Canberra. The next day her test comes back with a tick next to question 7. Canberra is right. Did Tara know the capital of Australia?

Right, but only by luck

Look at what Tara had. She believed "the capital of Australia is Canberra" - she wrote it down. And her belief was true. But almost everyone would say she didn't know it. She guessed, and she was lucky.

Now compare Tara with her friend Leo. Leo read about Australia last month, and he remembers that Canberra was built to be the capital so that neither Sydney nor Melbourne would get the job. Leo also wrote "Canberra". He and Tara wrote the same true answer. Only Leo knew it.

What luck leaves out

What does Leo have that Tara doesn't? Not a truer belief: both beliefs were exactly as true. Leo has reasons that connect his belief to the truth. He read it, and he remembers why. If the answer had been Sydney, the book would have said Sydney, and Leo would have written Sydney. Tara's guess had no such connection. It would have been Canberra whatever the answer was.

The same thing happens with a coin. Omid shouts "heads!" before the coin lands, and it lands heads. He was right. Did he know? No - he was right the way you are right half of the time when you call a coin.

A first idea of knowledge

So knowing something takes more than believing it, and more than the belief being true. A first idea of knowledge, which this course will fill in:

• you believe it;
• it is true;
• and you have good reasons for believing it - reasons that connect you to the truth, so that you are not right only by luck.

The next lesson looks at what makes a reason good.

Try it at home

1. Think of a time you got something right by guessing - a quiz answer, which door a friend would come out of, a score.
2. Did you know it, or were you lucky? How can you tell?
3. Now think of something you got right because you knew it. What did you have the second time that you didn't have the first?

Words to know

• guess - picking an answer without reasons that connect to the truth
• knowledge - a true belief that you have good reasons for

Big idea

A lucky guess can be right, but it isn't knowledge. To know something, you need to believe it, it must be true, and you need good reasons for it - reasons that would have led you to the truth whatever it was.