The Nature and Methods of Philosophy

U1 AOS 1

Valid

Logical and all premises result in the conclusion. All premises and conclusion are related to eachother so if the premises were true, then the conclusion would have been true as well.

Fallacious

Flawed

Premises

Exploration of argument. Statements/ evidence that come to a conclusion

Inductive reasoning

Observations that allow us to decide what seems most likely. A prediction that doesn’t guarantee certainty.

Deductive reasoning

Arguments result in certainty if premises are true and logic valid. Moves from general premises to a necessary conclusion.

Sound

Perfect argument- Premises are true and their link to the conclusion is valid. Validity + True Premises

Assertions

Answers. They indicate wether an argument is valid or fallacious, there are many techniques that form the branch known as logic.

Logic and reason

Methodical, reputable, and objective

Logic

The process of reaching a conclusion based as premises.

Structure for an argument

P1

P2

P3

Conclusion

Entaillement

All facts lead to another. Premises ‘entail’ the conclusion.

Necessary conditions

Sufficient conclusions

Words that indicate an INDUCTIVE argument

Low modality; Probably, maybe, and most.

Interrlocuter

Participants involved with the conversation, debate, or dialogue. They usually ask the questions. If the responder responds with a question, they are an interrlocuter. They can accept or offer a counter argument.

Socratic Dialogue

Made by socrates. Aims to guide individuals toward independent conclusions or recognise their own ignorance. A method of philosophical inquiry using structured questioning.

Limits of deductive reasoning

It requires us to be certain.

Limits on inductive reasoning

Reasoning isn’t correct, and the future doesn’t always resemble the past.

Logic

The process of reaching a CONCLUSION based upon statements known as PREMISES. 

Deductive reasoning example

P1) All men are mortal

P2) Socrates is a man

C: Therefore Socrates is mortal

Example of a NOT sound argument

P1) Iago is jealous of Othello

P2) Othello is easily manipulated

C: Therefore Othello Desdemona dies

Premises and conclusion are all true but the premises don’t necessarily result in the conclusion so it’s not valid or sound.

Why is it important to be rational?

Rationality is our distinguishing characteristic- arguments allow us to be persuaded to be more rational.

How is logic and reason beneficial?

What are the aspects of the Tripartite Soul?  Which are we hoping to mainly engage in when dealing with argument?

Head- rational (logic and thinking) heart- spirited (emotions and feelings) and appetitive (sex drive, need for food, etc)

Virtue

Acquired through habitual actions, not innate. It’s found in the Golden Mean. It leads to pleasure and well-being. The product of habituation guided by reason.

Argument to the Best Explanation

A way of reasoning where we infer that the best possible explanation for a set of facts to be true.

Deduction of different possibilities.

Example of Argument to the Best Explanation

1) Someone spilled water

2) The sink is leaking

3) A window was left open, and rain came in. Outside it hasn’t rained. The sink is dripping. Best possible explanation= The sink is leaking.

Nicomachean Ethics

Virtue isn’t an inherent quality, it’s rather acquired through repeated habitual events.

The Golden Mean

A scale between Excess and Virtue.

Reductio Ad Absurdum

Form of argumentation where a claims disproven by demonstrating that it’s logical conlusion leads to an absurd or contradictory result.

Trabscendental Arguments

Type of philosophical reasoning that seeks to establish the necessary conditions for the possibilities of certain concepts or experiences.

Analogies

Tools that draw parallels between conceptual and more tangible situations, emphasising similarities to aid in understanding or illustrating a point. E.g. Plato’s Cave

Thought Experiment

Hypothetical scenarios or imaginary situations made to explain philosophical or scientific ideas. Test without doing an experiment. E.g. Famous Violinist.

Inductive vs Abductive

Inductive reasoning generalises from observations, whereas abductive reasoning selects the most plausible explanation.

Cogency

For inductive arguments, cogency means strong reasoning and true premises.

Common Mistakes in Evaluating Arguments Assumptions

vague premises, and missing steps weaken an argument, contradictions within an argument, assuming the conclusion in the premises, arguing that one event must inevitably lead to another without sufficient evidence, and equivocation

Formal Fallacies

Errors in logical structure.

Informal Fallacies

Errors in reasoning due to content rather than structure.

Reflective Equilibrium

A method of refining moral beliefs through ongoing reflection and adjustment.

Logical asessment

Focuses on the structure of the reasoning:

Does the conclusion follow from the premises?

Would a rational person be persuaded if the premises were accepted?

Deductive argument is valid when

It’s impossible for premises to be true and the conclusion to be false.

The conclusion follows necessity from the premises.

The structure guarantees truth of the conclusion, even if the premises are false.

Features of validity

About form, not content.

A valid argument can have false premises

A deductive argument is either valid or invalid, with no in-between strength levels

Validity does not guarantee truth — that requires soundness

 

What are inducted arguments evaluated using?

Inductive reasoning is evaluated using cogency, not validity.

When is an inductive argument cogent?

-Premises are credible, reliable, and based on good evidence

-Conclusion is strongly supported, though not guaranteed

-The sample size or quality of evidence is appropriate

-No obvious counterexample weaken the generalisation

Inductive argument

Aims to give probability, not certainty. It moves from specific observations → a general or likely conclusion. The conclusions remain probable

Factual assessment

Even if an argument is logically perfect, it can still fail if its premises are not true or not reliable. Factual assessment checks the content of the argument, not just its structure.

4 main areas of factual assessment

Truth, speaker-relative propositions, assessing vague premises, and soundness

Truth in factual assessment

A statement is true when it accurately corresponds to the way the world actually is. This is often called the correspondence theory of truth.

A statement is true if

It describes reality correctly, and

The facts in the world match what the statement claims.

In philosophy, truth is

objective (not dependent on personal feelings)

independent of who says it

testable through evidence, logic, or observation

about the relationship between a claim and reality

A premise must aim to express something that can be true or false. Factual evaluation asks

Is this premise actually true?

Is there reliable evidence for it?

Does it rely on outdated, biased, or incomplete information?

An argument with one or more false premises cannot be

sound (even if the logic is valid).

What are speaker-Relative Propositions

Premises that depend on the perspective, context, or values of the speaker. These are not universally true or false.

Examples of speaker-relative propositions

Value judgments (“Chocolate is the best dessert”)

Contextual claims (“It is cold in here”)

Claims about personal preference or individual experience

Cultural or ethical claims that vary between communities

What to do when evaluating Speaker-relative propositions

Ask whether the premise is objective or subjective

Check whether the speaker assumes universality when only giving a personal claim

Look for hidden assumptions (e.g., “good”, “fair”, “better”, “important”) that must be clarified before evaluation

These propositions are not “wrong”, but they cannot ground a deductive argument unless supported by more general, shared claims.

What is are vague premises? Why are they problematic?

When it uses unclear or imprecise language that prevents proper evaluation. It cannot be clearly tested for truth. It may hide assumptions or exaggerations and can be interpreted in multiple ways, weakening the argument.

How to evaluate vague premises

Identify the word or phrase that is unclear

Ask: What exactly does this mean?

Rewrite or specify the premise if possible

Decide whether vagueness affects the argument’s strength or validity

A deductive argument is sound when

It is valid (the reasoning is structurally correct

All its premises are true in reality

-If either condition fails, the argument is not sound.

Affirming the consequent

formal fallacy that occurs in conditional ("if...then") statements. It mistakenly asserts the truth of the original statement based on the truth of the consequent where that truth is not sufficient to make valid the resulting conclusion.

Denying the antecedent

is also a fallacy which occurs in a conditional ("if...then") statement but is, in essence the reverse of affirming the consequent.  Thus it is made when one mistakenly concludes that the original statement is false based on the falsity of the antecedent (the "if" part).

Undistributed middle

This is a fallacy which is a mistake that can happen in categorical syllogisms, which are a way of making logical arguments using categories or groups. In this fallacy, the term that connects the two premises, known as the middle term, doesn't include all members of the group it should.

Is-ought fallacy

Highlights the difficulty of deriving moral or prescriptive conclusions directly from factual or descriptive observations.  This fallacy suggests that just because something is a certain way or is observed to happen (an "is" statement), it doesn't automatically imply how things ought to be or what actions are morally right (an "ought" statement).

Ad populum/ Appeal to the Bandwagon

A fallacy that argues something must be true or worthwhile simply because many people believe it or do it. The popularity of a belief is treated as evidence, even though widespread acceptance does not guarantee truth or correctness. This fallacy often relies on social pressure rather than reasons or evidence.  GROUP THINK

Ad Hominem

A fallacy when an argument is rejected by attacking the person making it rather than addressing the reasoning or evidence presented. By shifting focus from the argument to the speaker’s character, background, or motives, the discussion is diverted and the original claim is left unexamined.

Genetic fallacy

Occurs when an argument is judged as true or false based on where it comes from rather than on its reasoning or evidence. By focusing on the origin of an idea or the background of the person who presents it, the argument itself is ignored.

 

Key difference between Genetic + Ad Hominem fallacy

Genetic is judgement on a group whereas Ad Hominem is judgement on an individual

The Naturalistic Fallacy

An error in philosophy. Normative conclusions about what ought to be are wrongly derived from descriptive premises about what is natural. It happens when people mistakenly assume that if something occurs in nature, it is inherently good or right. G.E. Moore notably identified this fallacy in Principia Ethica. It suggests that ethical or moral judgments cannot solely be deduced from observable facts in the natural world. This highlights that what is natural is not necessarily morally acceptable, as ethical considerations transcend empirical observations.

The Conflating Morality with Legality

The Conflating Morality with Legality fallacy occurs when individuals erroneously assume that something is morally right or wrong based solely on its legal status. This fallacy arises from a failure to distinguish between ethical principles and legal regulations. Just because an action is legal does not necessarily make it morally just, and vice versa. This fallacy warns against equating legality with morality, urging a nuanced understanding that acknowledges the independent realms of ethics and law. It underscores the importance of considering ethical implications beyond legal frameworks and recognizing that not all morally right or wrong actions are explicitly addressed by the law.

Equivocation

Equivocation exploits the ambiguity of language by changing the meaning of a word during the course of an argument. The same term is used in different ways without clarification, making the argument appear sound when it is not. Because the shift in meaning is subtle, the conclusion can seem reasonable even though it is not properly supported.

The Amphiboly fallacy

The Amphiboly fallacy occurs when ambiguity in sentence structure or grammatical construction leads to misconstrued interpretations. It arises when a statement's syntax allows for multiple, often misleading, meanings due to poorly constructed or awkward language. Misunderstandings emerge as a result of the ambiguity, and individuals may draw incorrect conclusions based on different interpretations of the same statement. Recognising and addressing ambiguous language is crucial to avoid the Amphiboly fallacy, promoting clear communication and accurate understanding of the intended message. 

Composition and division

Fallacies when properties are wrongly transferred between parts and wholes.
The fallacy of composition: assumes that because each part of an argument shares a property, the whole formed by combining them must have it as well.
The fallacy of division: assumes that because a whole has a particular property, each of its parts must share it.

Error in both: ignoring how arrangement and interaction create properties that parts do not have independently.

Causal /Not a Cause for a Cause Fallacy

A fallacy when a causal connection is assumed between events without adequate evidence. Typically arises when one event is taken to have caused another simply because it happened earlier or occurred at the same time. The error lies in treating sequence or correlation as sufficient proof of causation, without ruling out coincidence or alternative explanations.

Problems with Arguments

-Inconsistency

-Begging the Question (Circular Reasoning)

-Slippery Slope

-Straw man

-False dilemma

The problem of inconsistency in arguments

When there are contradictions or conflicting elements within a set of premises or propositions. Inconsistency undermines the logical coherence of an argument, rendering it logically invalid. Philosophers strive for consistency to maintain the integrity of their reasoning. Identifying and addressing inconsistencies is crucial for constructing sound and persuasive arguments. Failure to rectify inconsistencies can weaken the overall philosophical stance, as it hinders the credibility and logical force of the argument. Philosophical rigor demands a commitment to coherence, and resolving inconsistencies is fundamental to ensuring the robustness of philosophical reasoning.

 

The problem of Begging the Question (Circular Reasoning)

-Argument assumes the truth of its conclusion within its premises. Rather than offering independent support, the reasoning merely restates the claim in a different form or relies on an unstated assumption that already presupposes what is being argued.

-Can appear persuasive while providing no genuine justification.

-The problem is not that the conclusion is false, but that it has not been meaningfully supported.

The problem of Slippery slope reasoning

Occurs when a claim is rejected on the basis that accepting it will inevitably lead to a chain of increasingly negative outcomes, without sufficient evidence for each step. It relies on exaggerated escalation rather than reasoned support and skips justification, often appealing to fear.

The problem of Straw man reasoning

When an argument is distorted or simplified in order to make it easier to attack. Instead of responding to an opponent’s actual claim, a weakened or exaggerated version is substituted and then criticised.

The problem is not disagreement but misrepresentation: by shifting the target, the original argument is left unanswered, and the discussion is diverted away from genuine evaluation of reasons and evidence.

The problem with False dilemma reasoning

When a situation is framed as offering only two mutually exclusive options, even though other reasonable alternatives exist. By artificially restricting the range of possibilities, the argument forces acceptance of one position simply because the other is rejected.

The problem lies not in drawing distinctions, but in ignoring complexity: real situations often allow for intermediate positions, multiple commitments, or responses that do not fit neatly into a binary choice.