Critical thinking revision
Unit 1: Evidence and credibility
Glossary
Argument – A set of claims, some presented as reasons, for accepting a further claim – the conclusion. Normally basic claims are put forward as reasons to support further claims.
Argument Indicators – Words commonly used to show reasons are being presented in support of a conclusion e.g. therefore, so, hence…
Assumption – A belief that is clearly accepted or taken for granted but is not stated or made explicit. Sometimes as explicit claim is called an assumption because no reasons have been given for accepting it or we wish to challenge the claim.
Belief – Claims or sentences that a certain person holds to be true or right. These can be scientific, religious, moral, prudential… A belief may be true or false.
Conclusion – A belief presented with reasons for accepting it. If a chain of reasoning is given then the final one is called the main conclusion and the previous ones are known as intermediate conclusions. A conclusion doesn’t necessarily come at the end of a statement. It could be a fact, a recommendation and interpretation, a decision…
Consistent / inconsistent – If two or more claims can both be true at the same time then they are consistent, if they cannot both be correct then they are inconsistent.
Contradiction – An inconsistency, where a claim is said to be both true or false – which it cannot be
Converse – The opposite of a hypothetical e.g. If A then B, if B then A. A converse is sometimes true but sometimes not.
Counter-example – The challenge of a general claim to weaken it.
Entails – A logically inescapable consequence
Fallacy – A pattern of reasoning that is mistakenly commonly used or any error in reasoning.
Flaws – A weak argument that gives little support to its conclusion.
Hypothetical – A sentence which has the general form if claim A then claim B.
Imply / Implication – Suggesting or leading to believe.
Inference – The step from reason to conclusion.
Knowledge – Knowing some fact, knowing how to do something, be acquainted with an object, place or person.
Necessary conditions – To say that A is a necessary condition for B is to say that A must happen in order for B to happen.
Sufficient conditions – To say that A is a sufficient condition for B is to say that if A happens then B will happen as well.
Principles – May be used in an argument as a reason conclusion or assumption, they have implications that go beyond the case in point.
Reasons – Supporting statements for a conclusion.
Supposition / supposition reasoning – A sentence beginning with a synonym for the word suppose which does not commit the speaker to a view. This reasoning is common in theoretical concepts.
Valid / invalid – Valid is used as a general term of approval. If the reasons are true then the conclusion will be true; the reasons cannot be true and the conclusion false. Validity is the relationship between reason and conclusion.
Assessing Credibility
An argument’s evidence will only be used if it is declared credible/believable. Credibility does not establish for certain what is true, but, after applying criteria in a disciplined way, it can be determined which is most likely.
Credibility criteria:
-Neutrality -Expertise -Ability to see
-Vested Interest -Reputation
-Bias -Experience
Neutrality
A neutral source is impartial – it does not take sides. There would be no reason or motive to lie therefore evidence shouldn’t be distorted or only one side of an argument presented.
Neutrality will increase credibility.
Vested Interest
A source holding vested interest in evidence will have something to gain or lose from promoting or defending a particular point of view. Evidence could be distorted, only certain bits selected, lies could be told to benefit a certain view point.
Vested Interest usually decreased credibility, unless it is a vested interest to tell the truth, then it would increase credibility.
Bias
A vested interest can lead to bias. If the source of evidence favours a particular side, see things in a certain way or has a preference for something, this is biased, however it doesn’t necessarily mean their evidence will be influenced by this. Bias can include prejudice, strongly held beliefs, irrational views and lack of impartiality and personal preferences and loyalties. The language used often gives an idea if there is bias involved. Bias can lead to deception and lies, as in propaganda (organized programme of publicity used to spread a particular view) and ethnocentrism (seeing their own group as the centre of everything)
Bias will decrease the credibility of evidence.
Expertise and Experience
If a source has specific knowledge, training, skills or familiarity with a subject then the evidence they give is likely to be judged more highly than from someone who is not an expert. However experts do get it wrong and standards of expertise change over the years so the date of the evidence has to be taken into account. Expertise and experience will only back up the evidence if it is relevant and the competence is in that certain area or field of training. However reasons to question experts can be because there is a disagreement between experts, incorrect judgments may be made, expertise and their advise can change over time and experts as a group can be seen as harmful.
Having Expertise and Experience will increase the credibility of evidence.
Reputation
If a source has a certain character, achievement, regard or standing this is their reputation e.g. honesty, fairness, exaggeration… and this will affect if the evidence they give is judged as credible.
In general, the higher the reputation, the more credible the source is seen to be.
Some newspapers have higher reputation than others. They are divided into upmarket broadsheets and down market tabloids. This used to refer to size however now come of the broadsheets are available in a smaller size. Quality broadsheets seem to have more detailed information from different view points, where as tabloids tend to contain more human interest stories and celebrity gossip. The hard news provided by broadsheets is deemed more credible than the gossip of tabloids.
Ability to see
It needs to be considered is the source of the evidence is primary or secondary i.e if they witnessed the event themselves or if they are reporting from hearsay.
First hand, eyewitness accounts are deemed more credible than hear say evidence.
If the event is witnessed first hand, then it can be judged how well the person could see the happenings e.g. there vision or hearing could be impaired, obstructions could prevent a clear view, there could have been distractions, it could have been dark…
If their ability to see is reduced then so will their credibility.
Corroboration
Corroboration refers to pieces of evidence which support each other, if evidence points in the same direction or tells the same story, it corroborates. The balance, weight and quality of evidence needs to be looked at as well as if the evidence corroborates. Uncorroborated evidence is a single account not backed up by anything else. This will lower the credibility of it. Credibility will be lowered even further is there is conflicting evidence – evidence saying different things which contradicts each other.
If evidence corroborates, credibility is increased, however if people are in fear of something, they may all tell the same false story.
Selectivity and representativeness
Evidence is always selected as all information cannot be included. Selection always has to happen and will always be incomplete as it is not practical or feasible to collect all information available.
We are unsure of facts given are representative of whole populations or participants have been selected to give specific results. Ideally, the evidence would be representative of the population or situation as a whole so it can be generalized. Researchers use a range of methods, such as random sampling so as to give everyone an equal chance of being chosen, as there is not time to question the whole population.
Evidence is sometimes specially selected in support of an argument and evidence going against the argument will be ignored. This type of selection is often made by vested interest or bias.
The presentation of unrepresentative information, biased samples or specially selected evidence will decrease the credibility of a source.
Context
This is the setting or situation in which evidence is produced. This includes things like ability to see and observing what happened, motives in misrepresenting the truth and the difficulties of judging what is true. We need to be aware of the context in order to see how it may have shaped the evidence. The context includes where the event happened, how many people were there, what year the evidence was written in, the political and economical views. Journalists reporting often depends on the context they get their information from and who or what they are biased towards. If evidence comes from questions and answers, these answers are given in a certain social context, i.e. a relationship with the interviewer. Social desirability can mean people want to present themselves in the best possible light so will emphasis their positive features and down play their negative ones. Interviewer effects can mean that people may respond to questions in terms of the way they are presented with it. The linguistic content can influence the answers people give by asking leading questions…
Observation and Eyewitness accounts
Most eyewitness accounts are seen as reliable and credible as they actually saw what happened instead of a distorted account that has been re-told. However, these eyewitness accounts show they are often unreliable and inaccurate.
There are many factors affecting observation:
Observation is based on the five senses, so if any of these are impaired then the credibility will be lessened e.g. partially sighted, colour blind, reduced hearing… Senses can also be affected by a number of factors, such as tiredness, drugs, alcohol… which may affect the accuracy of reports.
Context can also affect the accounts, such as time of the day, weather conditions, distance from the event, obstructions, distractions…
Perception, expectation and memory can influence accounts due to their pre-existing knowledge, experience, expectations and beliefs which can be used to reconstruct observations.
Bias and prejudice can distort accounts as people are not neutral.
Prior knowledge and expertise can mean that an observation can be shaped and reasons given.
Sources and types of evidence
Classification of evidence
Primary and Secondary sources: The distinction between primary and secondary sources varies in different areas. For historians, primary material consists of evidence from the period they are studying and secondary material is writings by historians which may include selected analyzed and interpreted evidence. In sociology, primary evidence is new material produced as part of their research and all other evidence not gained personally is secondary.
First hand and second hand evidence: First hand evidence is the same as an eyewitness account, meaning an event has been directly observed. Second hand evidence is hearsay or a report from some one who has the heard of the event from some one else. First hand evidence is usually seen as more credible as often when information is passed on details may be missed out or altered.
Direct and Circumstantial: These are legal terms used in courts of law. Direct evidence refers to eyewitness testimony and circumstantial evidence is non direct evidence which has been inferred or suggested.
Historical evidence
It is often hard to assess whether historical evidence is genuine. It is often worth a lot of money so people tend to fake it. History has been rewritten through doctoring of evidence such as forging documents and tampering with photos.
Time and evidence: Generally, the further back we go in time, the less evidence there is available and most of it is written from the viewpoint of the powerful so it is not representative of the whole population. Historians have to therefore construct the history of many people from no direct evidence therefore there credibility should be questioned.
Evidence from social sciences
Social scientists often use statistical data which can lead to problems as the data may not have been gathered in a fair way so may be unreliable. It is uncertain whether statistics measure what they claim to measure. Participant observation is one way of collecting information, however this can cause problems as people act differently when they are being watched. Interviews can also be shaped by investigator effects or social desirability and the samples are often not representative. Questionnaire results can also be difficult to trust as credible as the sample may not be representative, the questions may be ambiguous and unreflective of real life and may not measure what they are designed to measure. Experiments often cause problems as they are seen as artificial.
Internet Evidence
Assessing the credibility on internet sources is crucial as any one can set up a website airing their views, containing false information or being a reliable source. Reputation and neutrality will aid to credibility of websites. If a company is known for producing balanced reports it is likely they won’t report a hoax as they don’t want their reputation ruined. The writers of the article will affect the credibility, if they are experts we are more likely to believe them. Some government internet sites have a vested interest in bias in promoting a particular policy. Pressure groups will usually only present one side of an issue.
Making a reasoned judgment
Framework for making a judgment
When deciding which side to take, the judgment must be reasoned. It must be found by examining the evidence through looking at corroboration and conflict, balance of evidence, weight of evidence and quality of evidence in order to come to a reasoned judgment.