Reading-Story (Being logical)

Some tips about the book “Being logical”

Being logical 是一个常读常新的小书,对写论文或者是日常的交流都很有启发。按照自己的理解重新梳理下书中的章节,好多时候感觉即使是按照这样去做了,但事实上和别人交谈的时候还是有很多稀里糊涂的地方,于是索性就改清醒的时候清晰,比如弄论文相关的工作,该糊涂的时候糊涂,比如和别人交流的时候,得饶人处且饶人。正如知道菜是怎么样做的并不代表就会做菜一样,这些理论知识最终还是要应用到实践中才能有价值。

Defination of terms

subjective opinion, objective opinion

“A statement may be categorical in form but may not express what is objectively the case. A per-son may say, “The Chicago Cubs are the best team in base-ball.” That is a categorical statement, but what it tells us is that the person making it has no doubts about this particular matter. It reveals what is subjectively the case, because it declares what is, in fact, the speaker’s opinion. But it does not refer to any objective state of affairs.”

Actually, one mysterious part of daily talking is that it is hard to distinguish between the subjective opinion and objective opinion. Just keep in mind to respect differnet person’s opinion. When there is a new statement, instead of considering if it subjective, and judge other people by this standard (the objective point you think might be the subjective point of generated by your mind). We may consider, why other people give out this argument, and what are their premise, and what are the potential argument in their mind. They may not express their logical process in a complete form, then it is your show time to ask key questions and make the converseation more interesting and efficient instead of going to a wrong way because that the conflicts between your idea and other people’s idea.

For example, if other people say opinion A (it might be reasonable or not), then your opinion is B, if you say the B direactly, then the conversation may goes to a bad atmosphere. Since sometimes, we may tend to give out conclusion before give out the reasons carefully. If you start to ask why there are A. Then to discuss why the premise is complete, maybe the talk will become more interesting.


“When constructing an argument, the first thing to be mindful of is the two basic elements of argument: premises and a conclusion. You will not end up with an argument if you simply make statements. Your statements must be such that some of them (the premises) serve as the supporting data for another statement (the conclusion).”

When talking with other people, try to “burn your head” if you want to make the conversation more interesting. Describing the facts may be good, but at the most of the time, it is the “premise”, if other people describe the “premise”, try to do some logical process based on their opinion or statement. Just viewing this as a kind of game. The logical processes that contains all kinds of arguments can drive the converstation go far.

Sometimes I feel a little bit frastrated. Most of the time, we just discuss all kinds of arguments in conversation. But we still could not do it well, sometimes, we do not know other people’s premise, sometimes, there are issue in our reasoning processes. sometimes, we push other people accept our conclusion but we did not realize that our premises are different.

statement, arguments, opinion

Part2.7 Part3.13
“The purpose of the reasoning process, logic’s principal concern, is demonstration. I am not reasoning with you if I sim-ply say that such-and-such is true and expect you to accept it as true only on my say-so. I must show you that such-and-such is true, and I do that by making an argument. An argu-ment will only be as good as the statements of which it is composed, and those statements, in turn, will only be as good as the terms of which they are composed. Everything I have said thus far has been said with argument in mind. Argument is the activity of logic, and any particular argument is a concrete manifestation of the reasoning process.”

These sentences well describe how the argument is composed by the statement and how the statement is composed by the term. If we feel confused to understanding sth, we may start by term, then statement and then compose the argument. “Argument is the acticity of the logic, and any particular argument is a concrete manifestation of the reasoning process”

type of the arguments

Part 3.17

argument的类型可以大致地分为 deductive and inductive。日常生活中更多用到的是deductive的形式,基于的都是所谓的common knowledge,而在research 的论文中更多用到的是inductive (增量的,特殊到一一般的方式) 的方式。

For the deductive argument, the truth of the conclusion was already contained in the major promise.

The premise of inductive arguments are all the particular facts that go together to serve as a collection of evidence.

How the inductive argument start if we do not sure its premise? We start with the hypotheses, which is an educated guess as how things must be, or at lease, likely to be.

The whole scientific enterprise rests squarely upon inductive reasoning. Scientists are continullay gathering up specific bits of data to see what larger patterns can be discerned from them.

Inductive reasonging is ordered to making reliable generalization (i.e., those having a high degree of probability) about large group of things. But we still can not test all cases, the commonly strategy is to come up with a collection of individuals, a part of whole group, that is representative of the whole. It has to be sufficiently large that you can be reasonablely sure it contains wll the variety to be found in the group as a whole.

这些论述还是很有启发的,首先是一个通多inductive argument的方法来认识这个research的过程,然后就关注各个部分,premise是什么,conclusion是什么,bond 是否 tight 等等。看paper的时候,这个evaluation到conclusion的过程是否充分,选择的几个exp是否representative,这些都是构造inductive argument需要思考的点。

According to the description here and here, the casual reasoning can be viewed as another type of reasonging or argument that shows the reason and effect of two things. We may use an example to express how these different logic forms work.

According to the description here it is much reasonable to view the casual reasoning as a subtype of the inductive reasoning. Other type of inductive reasoning contains: sign reasoning, analogical reasoning and the generalization reasoning. Here are some other discussions, it looks that the premise and conclusion is the cause and effect in the causal reasoning.

The suffecient condition and essential condition. Simply speaking, the essential condition like A+B+C = D, where only A, B and C exist at the same time, we can get the conclusion D. The sufficient condition may like A->D, B->D, C->D one of the A, B or C exists, we can get the conclusion D.

Here, we try to use several examples to show how different reasoning works.

Inductive reasoning:

Premise: Becasue yesterday is ranining
Conclusion: The land is wet
(It maybe true or not, we just construct a causal reasoning here.)

Premise: I eat at restaurant several times, the dish is good
Conclusion: The dish at this restaurant is good
(There is no casual and effects here)

Becareful the inductive conclusion can be disproven by counter evidence and the conclusion is always tentative here.

how to evaluate the correctness of argument

Since the inductive reasoning is always tentative, it is important to know how to evaluate the correctness of the inductive reasonging and what are principles behind it.

Common strategy integrated in the deductive argument


Typical fallacies

It is still interesting to know what are common errors during the reasoning process, just list some key points here, there are all kinds of fallacies, and we take several items here:

Denying the anticedent

The tricky part is the fallacy based on the suffecient and necessary condition.

Assuming the basic logic form is


Then the A is the suffecient condition of the B.

One commen mistake is that when there is -A we get -B

so we easily thinking


actually, the A is only one sufficient condition, maybe the A2 or A3 can also derive to the B. so there is a mistake here.

Another more tricky case is that, the equicalent of the A->B is the -B->-A

some times we may naively get -B->A, from the A->B, which may make some mistakes.

The critical thinking perspective is still figure out if A is the sufficient condition of the B. Some times A is just the necessary condition of the B, the form is :


Then we naively thinking it is a sufficient condition. We can see that there is -A -> -B since A is the necessary condition to construct B.

Slippery slope

One simple example is that:

“If I go out with you Thursday night, I won’t be able to study for my test Friday. Then I will fail the test. Then I will fail the class. Then I will lose my scholarship. Then I will have to drop out of college. Then I will not get the career I want, and I’ll be 30 years old still living with my parents, unmarried, unhappy, and no children or career! That’s why I just can’t go out with you!”

This type of reasoning fails to look at alternate causes or factors that could keep the worst from happening

Essentially, it mixes the sufficient condition and the necessary condition. For every logic step, it is actually the A->B, since A is not the necessary condition, and we think there is -A->-B, but actually there is C->B or E->B so, the -A can not get the -B

Hasty generailization

This is an common mistake when we use the inductive reasoning. Especially when we write paper, it is important to show enough example to get a solid conclusion. In other words, the idea of the scope is very important. When we make the generilized conclusion, do not forgot the scope we are using.


Only show the weaker point of the opponent’s opinion. Straw man fallacy happens when an opponent in a debate misinterprets or takes a small part of their opponent’s position in a debate.

Red Herring(either or)

Red herring can distract from the original topic under discussion



Reasoning types

Really good and clear online material