1. Some Preliminary Obstacles to Thinking Critically
Cognitive biases and a few other loose ends

2. Cognitive Biases 1/18
The ugly truth: There are subconscious factors in belief formation.
These factors are called “cognitive biases”.

3. Cognitive Biases 2/18
Belief Bias: A highly believable conclusion (perhaps one already believed) can lead us to think that an (any) argument for that conclusion is a good one.

4. Cognitive Biases 3/18 For example, consider:
Grasshoppers have six legs.
All insects have six legs.
Therefore, grasshoppers are insects.

5. Cognitive Biases 4/18 This is a BAD piece of reasoning.
The obvious truth of the conclusion may make you blind to this. That’s belief bias.
Notice that the conclusion, together with the second premise, do properly yield the first premise. That is:

6. Cognitive Biases 5/18 This new argument... ... is a good one.
Grasshoppers are insects.
All insects have six legs.
Therefore, grasshoppers have six legs.
... is a good one.

7. Cognitive Biases 6/18
Belief Bias is, again, subconscious, but keep in mind:
If you have a certain view V on a serious issue, then it is worth having a good reason for V. To endorse every argument for V is to ignore the difference between the good reasons and the bad reasons for believing V.

8. Cognitive Biases 7/18 For example: Gay Marriage ...
1. Mitt Romney is anti-gay-marriage.
2. Mitt Romney is a genius.
3. Therefore, gay marriage is unacceptable.
... Is a BAD piece of reasoning.

9. Cognitive Biases 8/18 On the other hand, so is:
1. Mitt Romney is anti-gay marriage.
2. Mitt Romney is an idiot.
Therefore, gay marriage is acceptable.
The moral: Don’t check only the conclusion of an argument to determine whether the argument is any good! The fact that you endorse an argument’s conclusion is no reason to endorse the argument as a piece of good reasoning.

10. Cognitive Biases 9/18
Heuristics: Rules followed subconsciously in estimating probabilities.
Moore/Parker’s Example: Availability Heuristic: “[U]nconsciously assigning a probability to a type of event on the basis of how often one thinks of events of that type”

11. Cognitive Biases 10/18 For example ...
Watching lots of the evening news may lead one to think frequently about homicides in the U.S., which may in turn lead one to overestimate the likelihood of being a victim of a homicide in the near future.

12. Cognitive Biases 11/18
False Consensus Effect: The unjustified (though natural and subconscious) assumption that one’s attitudes are held widely in one’s society.
A philosophical example:
Reduction of all phenomena to physical phenomena

13. Cognitive Biases 12/18
Bandwagon Effect: The unjustified (though natural and subconscious) tendency to follow the crowd.
Why Rorschach Tests must be done individually!
“Magic Eye 3D”

14. Cognitive Biases 13/18 In-group Bias
Easier to form negative opinions of people who are not in our group than to form them of people who are.

15. Cognitive Biases 14/18
Kafka, “Community” (1920, my trans.): “We are five friends, we once came out of a house one after the other, one came first and positioned himself next to the gate, then ... came the second out of the gate and positioned himself not far from the first, then the third, then the fourth, then the fifth. At length we all stood in a row. The people were aware of us, pointed to us and said: ‘The five have now come out of this house.’ Since then we have lived together, and it would be a happy life, if a sixth had not immediately wanted to join us.

16. Cognitive Biases 15/18
“He does nothing to us, but he is burdensome to us, and that is to have done enough; why does he press himself in where no one wants to have him? We do not know him and do not want to take him in with us. Earlier, in fact, we five did not know each other, and if you will, we do not know each other even now, but what is possible and what is tolerated with the five of us is not possible and would not be tolerated with that sixth. Besides, we are five and do not want to be six....”

17. Cognitive Biases 16/18 Obedience to authority
Millgram Experiments (1960s)

18. Cognitive Biases 17/18
Overconfidence Effect/Better-Than-Average Illusion
American Idol
Most above average?

19. Cognitive Biases 18/18 How to Defend Against These?
Since they are subconscious phenomena, there is no way of stopping them once they have begun to affect our belief-forming processes.
But we can help to prevent them from arising altogether by STOPPING and THINKING CRITICALLY.

20. Always Think Critically?
Well, no.
Sometimes there’s no time!
It is often, perhaps always, easier or more expedient to act instinctively, or to act without much thought.
Sometimes things will turn out all right; sometimes it will cost you!

21. Truth and Knowledge If we reason critically, and reason well, we want:
(i) our conclusions to be true;
(ii) to know that our conclusions are true.
So ... What are truth and knowledge?
Topics for another class! But we can say a few things.

22. Truth
A claim (opinion, belief etc.) represents the world as being a certain way. So it is true just in case there is the right kind of correspondence between the world and the representation.
(If this doesn’t make any sense, just use your intuitive notion of truth!)

23. Knowledge A subject S knows that p only if:
S believes that p;
p is true;
S has good reason for believing that p.
(If this doesn’t make any sense, just use your intuitive notion of knowledge!)