Summaries of The Philosopher’s Toolkit

  • 1.10 – Definitions
  • 1.12 – Tautology, Self-Contradiction, Law of Non-Contradiction
  • 2.3 – Dialectic/Socratic Method versus Eristics and Apologetics
  • 2.4 – Analogies (Cave, Sun, Ship), illustration and Argument, Strong and Weak
  • 2.6 – Intuition Pumps, metaphor and imagery, not arguments
  • 3.18 -Charity and Fidelity versus Straw Man
  • 4.9 – Essence versus Accident
  • 4.13 – Necessary and Sufficient
  • 5.1 – Aphorism, Fragment, Remark
  • 5.3 – Socratic Elenchus and Aporia (impasse)


1.10 – Definitions

  • Define your terms, or it is easy to argue at cross purposes or commit the fallacy of equivocation.
  • Be precise and avoid vagueness or ambiguities.
  • Fix the definition for the purposes of your discussion. Others may argue that they have a better or alternative definition. This may lead them to reach different conclusions. You might respond by adopting the new definition, defending your original or proposing a new one. Any conclusion you reach apply only to those concepts as defined.
  • If too narrow, then it can’t be applied as broadly as hoped. In order to show that it is too narrow, point to the case that ought to be covered by the definition, but clearly isn’t.
  • If too broad, then indicate a case that fits the definition but which should clearly not be included. The ideal definition permits application of the term to just those cases to which it should apply – and to no others.
  • Rule of thumb – it is better if your definition corresponds as closely as possible to the way in which the term is ordinarily used in the kinds of debates to which your claims are pertinent, thought sometimes new terms may need to be coined.
  • There is a long philosophical tradition of quests for adequate definitions, that best articulates the concept in question. What counts as the best is debatable, and some terms evade precise definition. More recent thinkers (pragmatists and post-structuralists) hold that definitions are just conceptual instruments that organize our interactions with each other and the world but do not reflect any independent reality. Some propose that all philosophical puzzles are rooted in failure to understand how ordinary language functions.


1.12 – Tautology, Self-Contradiction, Law of Non-Contradiction

Tautology – a statement that is necessarily true, true in every possible world.

  • (p or not p)
  • all valid arguments can be restated as tautologies
  • empty or trivially true

Self-Contradiction – a statement that is necessarily false in every possible world.

  • (p and not p)

Law of Non-Contradiction – It is false that any statement can be both true and false.

  • Not (p and not p)
  • foundation upon which all logic is built
  • attempts to break it are themselves contradictions


  • Parmenides of Elea – “what is is and cannot not be’
  • Leibniz ‘identity of indiscernibles’



2.3 – Dialectic/Socratic Method versus Eristics and Apologetics

  • Eristic – principally concerned with winning arguments.
  • Apologetic – defending something already determined to be the truth.
  • Dialectic – Discovering or disclosing truths not yet (or no longer) known. A back and forth process between two or more points of view. One of the central features of philosophical education in medieval and Renaissance thought.
  1. One party advances a claim. (positive moment)
  2. Some ‘other’ party or parties advances some contrary claim or claims, or the ‘other’ launches into a critical analysis of the original claim, looking for incoherence or falsehoods or logical inconsistencies or absurd implications in the claim. (negative moment)
  3. The first party attempts to defend, to refine or to modify the original claim in light of the challenges brought by the other(s).
  4. The other(s)s responds to the first party’s defense, refinement or modification with newly refined criticisms or counterclaims
  5. Ultimately, a more sophisticated and/or accurate understanding of the issue at hand emerges.


  • Plato’s oneness, otherness, collection, and division – transcend the many images of the truth to grasp the one form of which those images are copies – ‘Divided Line’, ‘Charioteer of the Soul’; used to discern what makes things the same as one another and different from other things.


2.4 – Analogies (Cave, Sun, Ship), illustration and Argument, Strong and Weak



2.6 – Intuition Pumps, metaphor and imagery, not arguments



2.10 – Useful Fictions


Jean-Jacques Rousseau (1712-78) – social contract – an agreement by which we all manage to live together

  • is the act sanctioned by the social contract

John Rawls (1921-2002) – ‘ideal observer’ – the person who designed the political arrangements of the world from behind a ‘veil of ignorance’, not knowing what position in that society the observer would occupy.

  • derived from Adam Smith’s ‘impartial spectator’
  • constant figure to return to when deciding what is just, “what would the ideal observer’ say?

Friedrich Wilhelm Nietzsche (1844-1900) – ubermensch (overman) who would be able to overcome the nihilistic culture we endure and embrace the eternal recurrence, living this life again and again for eternity.

Different from most thought experiments

Useful fictions

  • …subspecies of thought experiment (used as part of an argument)
  • but serve a purpose beyond thought experiment

Useful in Explanation

  • Some maintained as explanatory tools


Don’t mistake fiction for fact.  Fictions are most useful when clearly fictional.


3.18 -Charity and Fidelity versus Straw Man



3.20 – Reductios

Hollywood ‘high concept comedies’ share something with the logical form reductio ad absurdum (RAA) , but while the comedies start from possible or plausible premises and end in hilarity, philosophical RAAs start with the premises of the position they undermine and end in absurdity, or contradiction, hoping to show that the premise must be wrong.

Plato demonstrates his mastery of the RAA in Book I of Republic in a discussion of justice. as repaying debts by countering with the example of returning weapons to a madman you know will use them to kill innocent people. (331e-332a).

RAAs are powerful because they allow us to suppose the opponent’s premise is true for the sake of the argument. “Suppose you are right. What would that lead to?” If it must lead to absurd or contradictory consequences, forcing the opponent to admit there is something wrong with their argument.

But Plato is charitable and assumes that he opponent must not mean that and offers a stronger interpretation, encouraging us not to abandon positions, but to refine them.

One problem with RAAs: when to accept the ‘absurd’ consequences, and when to abandon or modify our position? Are we left with only our intuitions to determine whether our position is absurd or just a surprise? It is truly absurd when it is a logical contradiction (proof by contradiction/reductio ad impossible), but returning a weapon to a madman is merely counter-intuitive, not logically contradictory. Reductios are not usually conclusive, rather they offer a choice to accept the consequence or reject the premises, often a hard choice but not a strict refutation.



4.9 – Essence versus Accident



4.13 – Necessary and Sufficient



5.1 – Aphorism, Fragment, Remark



5.3 – Socratic Elenchus and Aporia (impasse)



6.1 – Class Critique

Previous philosophers held that “human culture develops through the action of the thoughts, ideas and intentions of people, independently of the economic order in which they were produced.”

‘Class critique’ – “criticizing philosophical concepts and theories on the basis of the ways in which they serve or subvert class hierarchy or class struggle”

Classic example – Karl Marx and Friedrich Engels contended that “the mode of production …characteristic of a social order acts as a kind of ‘substructure’ built upon it” and “it is not the dynamics of ideas that determine society; it is the dynamics of the economic base that determine our ideas”…”determining the contents of our conscious minds without our even realizing it.”

Antonio Gramsci (1891-1937) said that the “culture can affect the economic substructure too.”

Examples of using tool of class critique

  • Protestant Reformation was not about a new religion but a result of capitalism deposing feudalism. Religion is a tool of the ruling class to mollify the exploited to dull their pain, an “opium of the people”.
  • ‘false consciousness’
    • e.g. liberal political rights were developed for the ruling class, are enjoyed by that class and are protected for that class and their interests.
    • US Civil War was not fought to end slavery but to clear the way for capitalist intervention in the American South.
    • Gulf and Iraq Wars were sold as protecting the people and their sovereignty, but was really to protect power in a strategic region to ensure European and US access to Middle East oil.

To use this tool, ask

  1. Does this help the ruling class , serve class interests, or promote resistance or revolution?
  2. Does it help manipulate and exploit subordinate classes, relieve their suffering or blunt resistance?
  3. How is this term used in practice?

Is it based on power and interest of the ruling class or on sound reasoning?


6.4 Feminist Critique

Philosophy describes the passions as forces to be dominated and controlled by reason; a reflection of concepts of male as rational and female as passionate, used by males to keep females subordinate.

  • Carol Gillgan
  • Helene Cixous
  • Nancy Chodorow
  • Margaret Benston
  • Heidi Hartmann
  • Mary Daly
  • Ruth Hubbard
  • Lorraine Code