Unit 2 Critical Thinking: the ba

2.1 Claims, assertions, statements

Claim is central to critical thinking.

Claims can be any form: texts, videos&audios, any documents...

A claim is what is expressed by a sentence. (the "meaning").

Here are some types of claims:

Fact and Opinion

You can state a fact only if it really is a fact. But you can claim that something is a fact and be mistaken, or even be lying.

    [A] Angola shares a border with Namibia.

    [B] The dinosaurs were cold-blooded.

    [C] Top bankers earn too much.

[A] is a (established/known) fact.

[B] is a claim (not statement/unknown) to fact. (No one knows it's right/wrong, but there is a fact existed.)

[C] is a purely opinion. (It depends on people. People differ in the standard of "too much" )

Value Judgment

Predictions and Probabilities

But you cannot, even with hindsight, say that the prediction was a fact when it was made.

Hypotheses (Theory)

Many scientific claims which are generally accepted, actually are not fact, but hypotheses.

Recommendations

"should be"...

2.2 Judging claims

If we questioned, or refused to believe, everything we read or heard, life as we know

it would come to a standstill.

But that does not mean we should respond with blind acceptance to everything that we read and hear. (fake documents, fake facts/beliefs, exaggerated/over-simplified ones, partial truths...)

Justification

When you evaluate claims..

Justified≠True

Justification is the process, while truth is about the claim itself.

For example, there could be a claim is true, but poorly justified. (by chance); Or, there could be a claim is false, but well justified.

Standards

马拉松那个例子。

严格讲，‘true’ means ‘the whole truth (does NOT allow degrees);

But, justification可以有不同程度 --- standards matters.

比如，法院审判： a guilty verdict is justified only if it can be proven beyond reasonable doubt. (无罪推定原则)

The balance of probability

There are degrees in justification in some cases. (e.g. civil cases)

Knowledge and certainty

(degrees of certainty)    near-certainty≠Certainty

But knowledge has certainty. (e.g. Mathematics and logic)

Complex claims

With connectives also considered.

Strong/Weak claims

Strong claims are more difficult to justified or easier to challenge.

Generalisations

e.g. "All men are ... than women".

【总结】

2.1    要有（从话语、文字各种材料中）提取有效claims的能力。(而不是迷失在情绪或是其他什么上面，特别是有的claims通过非常复杂隐晦的方式暗示出来，比如有的纪录片、电影、政治宣传).

2.2    要有evaluate/judge claims的能力。（从多大程度上，claim是可信的、正确的，抑或是根本不可信。而不是盲目相信一切---尤其是那些极富情绪煽动性和诱导力的claim）。