Answers to Problems from Logic: A Very Short Introduction
看完的第一本 VSI ~就当形式逻辑总算入了门(自称)。
翻译有够差的还是英文好。
没有人在被 treat well 的情况下反思现状,肯定是因为现实的痛苦。
VSI 这套好书迟早被这些译者毁了。
读书感想可能直接写在这里了。有空写写形式逻辑笔记。
答案有空补。会形式逻辑的可以在评论区回复哦~
Chapter 1
Is the following inference deductively valid, inductively valid, or neither? Why? Jose is Spanish; most Spanish people are Catholics; so Jose is Catholic.
Chapter 2
Symbolize the following inference, and evaluate its validity. Either Jones is a knave or he is a fool; but he is certainly a knave; so he is not a fool.
Chapter 3
Symbolize the following inference, and evaluate its validity. Someone either saw the shooting or heard it; so either someone saw the shooting it someone heard it.
Chapter 4
Symbolize the following inference, and evaluate its validity. Everyone wanted to win the prize; so the person who won the race wanted to win the prize.
Chapter 5
Symbolize the following inference, and evaluate its validity. You made an omelette, and you don't make an omelette and not break an egg; so you broke an egg.
Chapter 6
Symbolize the following inference, and evaluate its validity. It's impossible for pigs to fly, and it's impossible for pigs to breathe under water; so it must be the case that pigs neither fly nor breathe under water.
Chapter 7
Symbolize the following inference, and evaluate its validity. If you believe in God, then you go to church; but you go to church; so you believe in God.
Chapter 8
Symbolize the following inference, and evaluate its validity. It has always rained, and it always will rain; so it's raining now.
Chapter 9
Symbolize the following inference, and evaluate its validity. *Pat is a woman, and the person who cleaned the windows is not a woman; so Pat is not the person who cleaned the windows.
Chapter 10
Symbolize the following inference, and evaluate its validity, where the level of acceptability is 0.5. Jenny is clever; and either Jenny is not clever or she is beautiful; so Jenny is beautiful.
Chapter 11
The following set of statistics was collected from ten people (called 1-10).
$$ \begin{matrix} & 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 \\\\ \hline \text{Tall} & v & & v & & v & & & & v & \\\\ \text{Wealthy} & v & & v & & v & & v & v & & \\\\ \text{happy} & v & v & & v & v & & & v & v & \\\\ \end{matrix} $$
If r is a randomly chosen person in this collection, assess the inductive validity of the following inference. r is tall and rich; so r is happy.
Chapter 12
Suppose there are two illnesses, A and B, that have exactly the same observable symptoms. 90% of those who present with the symptoms have illness A; the other 10% have illness B. Suppose, also, that there is a pathology test t distinguish between A and B. The test gives the correct answer 9 times out of 10.
- What is the probability that the test, when applied to a randomly chosen person with the symptoms, will say that they have illness B?
- What is the probability that someone with the symptoms has illness B, given that the test says that they do?
Chapter 13
You hire a car. If you do not take out insurance, and you have an accident, it will cost you $1,500.
If you take out insurance, and have an accident, it will cost you $300.
The insurance costs $90, and you estimate that the probability of an accident is 0.05. Assuming that the only considerations are financial ones, should you take out the insurance?