Logical & Critical Thinking by Sabrina Mulholland Jjones

tajana_tusek — 2018-02-15 12:26:43 UTC

Confirmation bias - when we tend to only consider what we have already experienced.
Heuristics - mental shortcuts we use to simplify decision making.
Framing - when how we are presented with a problem affects the way we see it.
Common fallacies - some common ways that we use reasoning that are not logical or critical.

Conformation bias

tajana_tusek — 2018-02-17 05:58:20 UTC

“The human understanding, when it has once adopted an opinion draws all things … to support and agree with it. And though there be a greater number and weight of instances to be found on the other side, yet these it either neglects and despises or … sets aside and rejects in order that by this great and pernicious predetermination, the authority of its former conclusions may remain inviolate”.

(Francis Bacon 1602).

Heuristics

tajana_tusek — 2018-02-17 05:59:19 UTC

Reasoning heuristic - A mental shortcut to simplify decision making is called
Availability heuristic - We judge the probability of an event by how quickly and easily examples of that event come to mind, by how available they are to us, rather than by identifying all of the alternatives and working out the real probabilities.

Species of Fallacious Arguments

tajana_tusek — 2018-02-18 11:40:44 UTC

An argument is simply a way to describe the way in which reasons support beliefs.

tajana_tusek — 2018-02-18 14:07:35 UTC

How to evaluate an argument

Identify the conclusion and the premises.
Put the argument in standard form.
Decide if the argument is deductive or non-deductive.
Determine whether the argument succeeds logically.
If the argument succeeds logically, assess whether the premises are true. For premises that are backed-up by a sub-arguments, repeat all the steps for the sub-arguments.
Make a final judgement: is the argument good or bad?

Statements

tajana_tusek — 2018-02-19 21:08:03 UTC

Statements are the kind of sentences that are either true or false.

Non-statements

tajana_tusek — 2018-02-19 21:17:46 UTC

Questions (except rhetorical)
Commands
Advice

Arguments

tajana_tusek — 2018-02-19 22:06:05 UTC

An argument is a group of statements some of which, the premises, are offered in support of another statement, the conclusion.

Conclusion indicators | Premise indicators

tajana_tusek — 2018-02-19 22:15:16 UTC

Validity

tajana_tusek — 2018-02-26 22:03:14 UTC

A deductive argument is an argument for which the premises are offered to provide logically conclusive support for its conclusion.

Strength

tajana_tusek — 2018-02-26 22:06:58 UTC

A non-deductive argument is an argument for which the premises are offered to provide probable – but not conclusive – support for its conclusions.

Evaluating arguments

tajana_tusek — 2018-02-27 21:04:38 UTC

1. Do the premises provide enough logical support for the conclusion?
2. Are the premises true?

Valid argument

tajana_tusek — 2018-02-27 21:05:10 UTC

A deductive argument that succeeds in providing decisive logical support.

Is it possible for the premises to be true and the conclusion to be false? (No)

An argument is valid if and only if there are no counter-examples to the argument, as it is then impossible to find a situation in which the premises of the argument are true and the conclusion is false.

Strong argument

tajana_tusek — 2018-03-01 20:21:58 UTC

A non-deductive argument that succeeds in providing probable, but not conclusive, logical support for its conclusion.

A weak argument

tajana_tusek — 2018-03-01 20:22:25 UTC

A non-deductive argument that fails to provide probable support for its conclusion.

tajana_tusek — 2018-03-04 19:55:10 UTC

There is a possibility that the conclusion may be false.

Invalid argument

tajana_tusek — 2018-03-05 10:10:36 UTC

A counter-example to a deductive argument

tajana_tusek — 2018-03-06 11:50:10 UTC

is a situation which shows that the argument can have true premises and a false conclusion.

If the argument being evaluated is deductive, then we can show it to be invalid and, therefore, bad if we can describe a counter-example.

A counter-example to a non-deductive argument

tajana_tusek — 2018-03-08 12:59:29 UTC

Since a non-deductive argument acknowledges that the conclusion might be false when the premises are true, but only in exceptional circumstances, you need to find a counter-example that is not so exceptional (a reasonable situation in which the premises are all true and the conclusion false).

If all you can come up is too far fetched, then you’re probably describing one of the exceptional cases that were excluded to begin with, and so you would fail to provide a counter-example, and you could conclude that the argument is strong.

tajana_tusek — 2018-03-11 12:59:52 UTC

Implausible counter-examples are counter-examples all the same, but they can only show that a deductive argument is invalid. However, only a plausible counter-example can show that a non-deductive argument is weak.

If the only counter-examples you can find are far-fetched stories, then you may have an indication to think that the argument is non-deductive.

tajana_tusek — 2018-03-11 13:01:06 UTC

You might also think of the search for a counter-example as a method that helps you determine whether an argument is deductive or non-deductive. If finding a counter-example to an argument makes us want to say that argument is no good, then the argument must be deductive, because in deductive arguments the premises are intended to give conclusive support for the conclusion.

On the other hand, if generating a counter-example does not incline us to give up the argument, then it is a non-deductive argument because non-deductive arguments have conclusions which are only meant to be strongly suggested by their premises, and leave it open that the conclusion may be false.

Counter-examples show invalidity / weakness of an argument

tajana_tusek — 2018-03-11 18:28:36 UTC

A sound argument is a valid argument that has true premises.

tajana_tusek — 2018-03-11 19:29:05 UTC

A sound argument is a deductive argument. It’s trying to establish conclusive support for its conclusion.
The argument is valid: the premises, if true, would guarantee that the conclusion is also true.
The premises are actually true

Therefore, a sound argument guarantees that its conclusion is true.

A cogent argument is a strong non-deductive argument that has true premises.

tajana_tusek — 2018-03-11 19:32:01 UTC

A cogent argument is by definition non-deductive, which means that the premises are intended to establish probable (but not conclusive) support for the conclusion.
A cogent argument is strong, so the premises, if they were true, would succeed in providing probable support for the conclusion.
The premises are actually true.

So the conclusion indeed receives probable support.

tajana_tusek — 2018-03-13 12:28:04 UTC

For deductive arguments, a premise is relevant if removing it makes a valid argument invalid.

tajana_tusek — 2018-03-13 12:29:17 UTC

Irrelevant premises do not make arguments bad by making them invalid. They make them bad (non-cogent) when they are false. So what should you do with irrelevant premises? Apply the principle of charity and remove them from the argument. Call this, pruning an argument.

Non-deductive arguments

tajana_tusek — 2018-03-13 12:30:44 UTC

A premise is irrelevant if having it in the argument does not make it stronger and removing it from the argument does not make it weaker.

How to evaluate real-world stuff

tajana_tusek — 2018-03-18 21:58:37 UTC

What, if any, statements does this passage contain?
If it’s an argument, what’s the conclusion? And what premises are supplied?
If it’s an argument, does it have any suppressed premises? If so, what are they?
How does the whole argument look in standard form with all premises made explicit?
Is the argument deductive or non-deductive?
If it’s deductive, is it valid? If it’s non-deductive, how strong is it? Can you think of a (plausible) counter-example?
Are the premises true?
So, is it a good or a bad argument?

tajana_tusek — 2018-03-18 22:53:54 UTC

Verification shows something to be true
Falsification shows something to be false.

tajana_tusek — 2018-03-22 11:04:40 UTC

tajana_tusek — 2018-03-22 11:05:08 UTC

Non-falsifiable hypotheses are not scientific.

tajana_tusek — 2018-03-22 21:14:13 UTC

Inference to the best explanation (is a non-deductive argument

tajana_tusek — 2018-03-22 21:17:53 UTC

S is a state of affairs, a collection of data, facts, observations, givens.
A hypothesis, H, would, if true, explain S.
No other hypothesis can explain S as well as H does.
Therefore, probably,
H is true.

tajana_tusek — 2018-03-22 21:20:47 UTC

Explanations aren't arguments.

Scientific practice includes particular processes and methods designed specifically to remove the influence of at least the more common and serious obstacles to good logical and critical thinking as done by scientists.

tajana_tusek — 2018-03-24 21:09:08 UTC

Scientific thinking is a subset of logical and critical thinking

tajana_tusek — 2018-03-25 12:37:56 UTC

"Theory" in science

tajana_tusek — 2018-03-25 20:34:21 UTC

A technical term used to describe a comprehensive account of some aspect of nature, supported by a large body of converging evidence, based on repeated observations and testing, usually integrating and generalising hypotheses, and making consistently accurate predictions across a broad area of scientific inquiry.

tajana_tusek — 2018-03-30 11:23:30 UTC

Scientific claims are falsifiable: there are observable outcomes that would be impossible if the claim were true.

tajana_tusek — 2018-03-30 11:40:59 UTC

Scientific theories are not ‘mere’ theories – untested, tentative, vague generalisations. They are, instead, comprehensive, supported by large bodies of converging evidence, based on repeated observations, usually integrating and generalising hypotheses and making consistently accurate predictions across a broad area of scientific inquiry

Reasoning by analogy

tajana_tusek — 2018-03-30 12:09:19 UTC

P is similar to Q in certain known respects.
P has some further feature– R.

Therefore, probably,

Q also has the feature R.

Burden of proof

tajana_tusek — 2018-04-02 09:38:35 UTC

To have the burden of proof is to be rationally required to produce evidence for your assertion claims.
Burdens of proof come in degrees.
To have a heavier burden of proof than some opponent is to be rationally required to produce more or better evidence for your assertion claims than your opponent is rationally required to produce.

The legal example: People accused of crimes are presumed innocent. The burden of proving that they are guilty rests on the prosecutor. The accused doesn’t have to prove anything. If the prosecutor doesn’t meet the burden, the presumption that the accused is innocent stands: Innocent until proven guilty.

We think unequal allocation of the burden of proof is only legitimate in truth-directed practices in the unusual situation in which such an allocation does make it easier to establish the truth (such as where one party has exclusive access to evidence (the Tax case), or the motives for enquiring in an issue are unusually divided between the parties (the buyer-beware case). We think allocating the burden of proof equally fits better with the ideas that good reasoners should always be able to provide reasons for their assertions; that argument is ‘truth-seeking’: concerned to lead us to hold true beliefs and reject false beliefs; that in truth directed inquiries you are almost never entitled to rely upon your opponent’s inability to show that their view is true.

A (bad) science example (BOP)

tajana_tusek — 2018-04-02 10:03:30 UTC

“The “no acid, no ulcer” consensus was treated as a default position, to be abandoned reluctantly, and only in the face of overwhelming evidence. The mistake, we suggest, was essentially getting the allocation of the burden of proof wrong, placing too heavy a burden on the bacterial theory”.

Authority

tajana_tusek — 2018-04-05 18:22:13 UTC

The authority has to have sufficient expertise.
It has to act within its area of expertise.
Its claims have to be consistent with a reasonable consensus in the area.
It has to act sincerely and free of bias.
It is only OK to resort to an authority if the reasoner themselves lacks expertise.

Fairness

tajana_tusek — 2018-04-05 18:52:02 UTC

historical
substantive

tajana_tusek — 2018-04-05 19:27:48 UTC

All moral statements are normative statements.
But not all normative statements are moral statements.

A descriptive statement

tajana_tusek — 2018-04-05 19:27:55 UTC

gives an account of how the world is without saying whether that's good or bad.

A normative statement

tajana_tusek — 2018-04-05 19:28:28 UTC

expresses an evaluation, saying that something is good or bad, better or worse, relative to some standard or alternative.

A moral statement

tajana_tusek — 2018-04-05 19:28:55 UTC

is a claim that something is morally good or bad, right and wrong, or has some other moral quality, such as being just, admirable, or blameworthy.

A moral argument

tajana_tusek — 2018-04-05 19:29:40 UTC

is an argument that includes at least one moral statement.

Is-Ought Problem

tajana_tusek — 2018-04-07 05:05:54 UTC

A valid deductive argument with a moral conclusion must have at least one moral statement in the premises to the argument.

Distinction between moral and scientific theories

tajana_tusek — 2018-04-08 20:20:59 UTC

Moral theories are not mere theories in the dismissive sense either. They too are based on repeated observations, are likely to integrate hypotheses, and attempt to explain and justify a range of moral or ethical judgements about particular cases.

But neither are moral theories quite like scientific theories. The data that scientific theories try to explain is provided by observation of the natural world. The data that moral theories try to explain is our considered moral judgements; judgements that have, we might say, survived the test of good logical and critical thinking. There is an obvious difference here. In the case of moral theories, we use our considered judgements to supply the data by which we judge the adequacy of moral theories.

Still, even with this difference acknowledged, we do use moral theories, and often in very similar ways to their scientific counterparts.

Moral theories offer general accounts of what makes an action right, accounting for as many of our considered judgments as possible (just as the scientists attempts to explain as many observations as possible), sometimes calling upon us to abandon some of those judgments, (just as scientists might reject some observations or hypotheses as mistaken), attempting to explain why a judgment in some past case is troubling and how we should judge in the future.

There is, however, one other important way in which moral theories are not like scientific theories:

In science, we assume that there is one right theory and that it will explain all of the data and probably lead us to abandon rival theories (though it may have incorporated significant parts of them). Moral theories do not seem to work quite like that. They are generated by our considered moral judgments and they reflect, for instance, the judgment that consequences matter; that recognition and respect for autonomous reasoning agents matter; that wisdom and judgment matter. Moral theories allow us to see the implications of the judgments that these (and other fundamental concerns) are each important in moral reasoning.

Moral theories are not ‘mere’ theories – untested, tentative, vague generalisations. They are based on repeated observations, integrated hypotheses, and attempt to explain a range of data. But the data that scientific theories try to explain is provided by observation of the natural world, the data that moral theories try to explain is our considered moral judgements; judgements that have, we might say, survived the test of good logical and critical thinking.

Act utilitarianism

tajana_tusek — 2018-04-08 20:22:21 UTC

Thee right action is the one that generates the most utility, understood by early proponents as the greatest happiness for the greatest number of people. The theory claims that right actions have a common property – their tendency to generate utility.

An important alternative theory responds to the fact that utilitarianism makes moral rightness depend upon what in fact would make people happy. According to Immanuel Kant, the ultimate principle of morality must be capable of guiding us to the right action in any circumstances. He tells us to ask if the motive we are considering acting from could become a universal law, a law to be followed by anyone in any situation. He is concerned with consistency and rationality, not consequences.

A further alternative theory downplays rules and principles, emphasising the importance of ‘practical wisdom’ in particular cases. The right action, according to Aristotelian virtue theory, is the action that would be chosen by an agent who has practical wisdom. But how are we to identify the person of practical wisdom? We can’t do so by seeing if they choose the right action, since the right action is the action they choose! (if we can work out whether they’ve chosen the right action on some other ground – utility maximization or respect for persons, perhaps? – that would be the test for right action, not the choice of the person of practical wisdom).

Moral relativism

tajana_tusek — 2018-04-08 20:48:55 UTC

Ethics then is not just a matter of taste. We can make sense of the idea of genuine moral disagreement, it seems to make perfectly good sense to try to convince people they are mistaken about ethical matters, and we change our minds about such matters in response to argument and reason.

tajana_tusek — 2018-04-08 20:52:33 UTC

Subjectivists claim that ethical statements report things about the utterer rather than about the world.

Course

tajana_tusek — 2018-04-08 21:04:56 UTC

Quizes

tajana_tusek — 2018-04-08 21:06:10 UTC

http://philosophy.lander.edu/logic/tvs_quiz.html

Ethical reasoning

tajana_tusek — 2018-04-08 21:13:16 UTC

Prejudices, purely emotional responses, and empirically implausible positions are not the only sorts of reasons that are unacceptable in moral discourse – blind appeals to authority may well go on the list as well – but they will be enough to give a sense of the constraints posed by the requirement for reason giving.

Perhaps most importantly, the role of reasons imposes a constraint of consistency. Consistency requires that if there are exactly the same reasons in support of one course of action as there are in support of another, then those actions will be equally right or equally wrong – they will be equally well supported or undercut by reasons.

If I object to racism on the grounds that ‘all people are equal’ then I must also object to those manifestations of other prejudices, such as sexism, that deny that principle: If I do not then it will seem that in one or other or both of the cases I am not really accepting ‘all people are equal’ as a reason at all. My position will not, in fact, be based on the reason or reasons I cite.

Good ethical reasoners must be able to reason logically, to avoid fallacies and inconsistencies, to clarify and analyze concepts, to construct and assess arguments and positions.

Fallacies

tajana_tusek — 2018-04-08 21:16:38 UTC

False dichotomy - is a type of informal fallacy in which something is falsely claimed to be an "either/or" situation, when in fact there is at least one additional option.
False compromise ?
Ambiguity is a type of uncertainty of meaning in which several interpretations are plausible. It is thus an attribute of any idea or statement whose intended meaning cannot be definitively resolved according to a rule or process with a finite number of steps.
Framing
Conformation bias

Smell Study

tajana_tusek — 2018-04-09 09:58:35 UTC

Quizlet

tajana_tusek — 2018-04-23 09:56:43 UTC