There is a physical sound present, but there is no sound experience. It is logical to think that things occur even if there is nobody to see/hear/taste them since changes can be observed (If you leave a burning paper and come later, it will be burnt)
The tables in the classroom – Do tables dance when nobody is around? It is improbable for such a thing to exist, therefore it is considered false, since it is impossible to prove. Theories of reality Common-sense realism – the world is the way we perceive it (“What you see it what is there”) Scientific realism – The world exists independently but is different from what we perceive it as (“Atoms in the void”) Phenomenalism – We can only know what we perceive – (“to be is to be perceived” Most theories suggest the existence of an independently existing reality (Things happen also without people).
Reason Using reason we gain knowledge that is beyond the immediate evidence of our senses. Rationalism – school of philosophy according to which reason is the most important source of knowledge – even more than experience Premises – The assumptions in logic, conclusions follow from them Fallacies – invalid patterns of reasoning Deductive reasoning i?? Moving from the general to the particular.
Syllogisms – A kind of argument that includes: Two premises and a conclusion Three terms, each occurring twice Quantifiers (all, some, no) Truth = a property of statements Validity = a property of arguments An argument is valid if the conclusion follows logically from the premises and invalid when it doesn’t. Trueness is independent on validity. The structure of arguments Validity of a syllogism doesn’t depend on the words used but on the structure. It is possible to substitute the elements for anything else and the validity won’t change. (A -; B is the same as seeds-;plants when speaking of validity).
A fallacy called brief bias is based on concentrating not on the structure but the words themselves which may lead to false conclusions. Venn diagrams – are a useful tool when deciding whether a syllogism is valid. However, Venn diagrams contain extra information which should NOT be considered as given in the first place. Deductive reasoning preserves truth – if the premises are both true then the conclusion must be true. Enthymeme = an incomplete argument (e. g. Jenny goes to Oxford so she must be intelligent) All deductive reasoning is based on inductive reasoning – experience Inductive reasoning i??
Moving from the particular to the general Is based on experience and observation which allows to draw conclusions Deduction and induction compared Deduction Reasoning from general to particular All metals expand when heated A is a metal -;A expands when heated More certain, less information than Induction How reliable is inductive reasoning’sometimes we make hasty generalizations. Sometimes, even well supported inductions are proved wrong. Confirmation bias – people only see things supporting their theories and ignore exceptions.
Good generalizations 1) Number – need to look at a large number of examples to be able to make a generalization 2) Variety – variety of circumstances – different types 3) Exceptions – actively look at counter-examples 4) Coherence – more evidence for unlikely things 5) Subject area – some areas are more certain than others (maths>biology) Informal Reasoning The ten deadly fallacies:
Ad ignorantiam Hasty generalization Post hoc ergo propter hoc Ad hominem Circular reasoning Special pleading Equivocation False analogy Claiming something is true because it cannot be proved false Generalizing from insufficient evidence Confusing a correlation with a causal connection Attacking/supporting the person rather than the argument.
Assuming the truth of what you are supposed to be proving Using double standards to excuse an individual or a group Using language ambiguously Assuming that because two things are alike in some aspects, they are alike in others Assuming that only two black and white alternatives exist A question that is biased because it contains a built in assumption Post hoc ergo propter hoc The fact that two things follow after each other doesn’t necessarily mean that one is the cause of the other. (e. g. Day is not the cause of night) Ad hominem fallacy (“against the man”) Not arguing – attacking/supporting the person.
(e. g. What do YOU know about it? You’re just a child! / Obama says it so it must be right) Circular reasoning (vicious circle / begging the question) Arguing with the thing that needs to be proven. (e. g. God must exist because dictated wrote the bible) Special pleading Exceptions for certain people (e. g. politician immunity) Equivocation Word used in two different ways in an argument (A hamburger is better than nothing and nothing is better than good health => hamburger is better than good health) Argument ad ignorantiam Saying something is true on the basis thet it cannot be proved wrong.
– God exists. – Do you have any proof that he does? – Do you have any proof that he does not’so he must. False analogy Using analogies that are not logically correct – only a rhetorical device (e. g. comparing rain to human problems) False dilemma Only putting something as black and white – suggesting binary thinking when there are other options as well (e. g. You either climb that tree or you will NEVER conquer your fear! ) Loaded questions Questions that contain suggestions and cannot be answered in a yes/no manner while not telling anything. (e. g. Do you always cheat on your exams? )
Causes of bad reasoning The main reasons are ignorance, laziness, pride and prejudice. We misuse rhetorical skills in order to persuade people – sometimes we even argue about things which we know are wrong rather than coming to the correct conclusion. Reason and certainty Laws of thought: The law of identity – If A then A. The law of non-contradiction – If A is A then it is not non-A The law of the excluded middle – Everything is either A or non-A. Nothing is both. Can deductive reasoning be doubted? “Reason is a matter of faith” Some things are unsure and unable to be categorized properly (day/night)
Everything is constantly changing? Can inductive reasoning be doubted? Induction is hard to apply for all rather than all observed Prison of consistency – When you take a position on something, it is difficult to change it without losing face or to look at it from a different perspective. (It is hard to find errors in my own test) .