Combining Philosophers

All the ideas for Horsten,L/Pettigrew,R, Thrasymachus and Henry Sidgwick

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14 ideas

5. Theory of Logic / A. Overview of Logic / 9. Philosophical Logic
Three stages of philosophical logic: syntactic (1905-55), possible worlds (1963-85), widening (1990-) [Horsten/Pettigrew]
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
Logical formalization makes concepts precise, and also shows their interrelation [Horsten/Pettigrew]
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
Models are sets with functions and relations, and truth built up from the components [Horsten/Pettigrew]
7. Existence / A. Nature of Existence / 1. Nature of Existence
If 'exist' doesn't express a property, we can hardly ask for its essence [Horsten/Pettigrew]
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
A Tarskian model can be seen as a possible state of affairs [Horsten/Pettigrew]
The 'spheres model' was added to possible worlds, to cope with counterfactuals [Horsten/Pettigrew]
10. Modality / E. Possible worlds / 1. Possible Worlds / b. Impossible worlds
Epistemic logic introduced impossible worlds [Horsten/Pettigrew]
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
Possible worlds models contain sets of possible worlds; this is a large metaphysical commitment [Horsten/Pettigrew]
Using possible worlds for knowledge and morality may be a step too far [Horsten/Pettigrew]
16. Persons / F. Free Will / 2. Sources of Free Will
If we say that freedom depends on rationality, the irrational actions are not free [Sidgwick]
23. Ethics / A. Egoism / 1. Ethical Egoism
Self-interest is not rational, if the self is just a succession of memories and behaviour [Sidgwick, by Gray]
23. Ethics / E. Utilitarianism / 1. Utilitarianism
It is self-evident (from the point of view of the Universe) that no individual has more importance than another [Sidgwick]
24. Political Theory / D. Ideologies / 4. Social Utilitarianism
Sidwick argues for utilitarian institutions, rather than actions [Sidgwick, by Tuckness/Wolf]
28. God / C. Attitudes to God / 3. Deism
Clearly the gods ignore human affairs, or they would have given us justice [Thrasymachus]