65 ideas
| 12926 | Wisdom is the science of happiness [Leibniz] |
| 12903 | Wise people have fewer acts of will, because such acts are linked together [Leibniz] |
| 12914 | Metaphysics is geometrical, resting on non-contradiction and sufficient reason [Leibniz] |
| 12915 | Definitions can only be real if the item is possible [Leibniz] |
| 19333 | A truth is just a proposition in which the predicate is contained within the subject [Leibniz] |
| 12910 | The predicate is in the subject of a true proposition [Leibniz] |
| 4901 | Truth has to be correspondence to facts, and a match between relations of ideas and relations in the world [Perry] |
| 18739 | Three stages of philosophical logic: syntactic (1905-55), possible worlds (1963-85), widening (1990-) [Horsten/Pettigrew] |
| 18741 | Logical formalization makes concepts precise, and also shows their interrelation [Horsten/Pettigrew] |
| 18744 | Models are sets with functions and relations, and truth built up from the components [Horsten/Pettigrew] |
| 12920 | There is no multiplicity without true units [Leibniz] |
| 18740 | If 'exist' doesn't express a property, we can hardly ask for its essence [Horsten/Pettigrew] |
| 12319 | What is not truly one being is not truly a being either [Leibniz] |
| 12922 | A thing 'expresses' another if they have a constant and fixed relationship [Leibniz] |
| 13079 | A substance contains the laws of its operations, and its actions come from its own depth [Leibniz] |
| 12745 | Philosophy needs the precision of the unity given by substances [Leibniz] |
| 12921 | Accidental unity has degrees, from a mob to a society to a machine or organism [Leibniz] |
| 12746 | We find unity in reason, and unity in perception, but these are not true unity [Leibniz] |
| 12916 | A body is a unified aggregate, unless it has an indivisible substance [Leibniz] |
| 12919 | Unity needs an indestructible substance, to contain everything which will happen to it [Leibniz] |
| 12923 | Every bodily substance must have a soul, or something analogous to a soul [Leibniz] |
| 12704 | Aggregates don’t reduce to points, or atoms, or illusion, so must reduce to substance [Leibniz] |
| 13077 | Basic predicates give the complete concept, which then predicts all of the actions [Leibniz] |
| 12908 | Essences exist in the divine understanding [Leibniz] |
| 12706 | Bodies need a soul (or something like it) to avoid being mere phenomena [Leibniz] |
| 12906 | Truths about species are eternal or necessary, but individual truths concern what exists [Leibniz] |
| 4885 | Identity is a very weak relation, which doesn't require interdefinability, or shared properties [Perry] |
| 4899 | Possible worlds thinking has clarified the logic of modality, but is problematic in epistemology [Perry] |
| 18745 | A Tarskian model can be seen as a possible state of affairs [Horsten/Pettigrew] |
| 18747 | The 'spheres model' was added to possible worlds, to cope with counterfactuals [Horsten/Pettigrew] |
| 18748 | Epistemic logic introduced impossible worlds [Horsten/Pettigrew] |
| 18746 | Possible worlds models contain sets of possible worlds; this is a large metaphysical commitment [Horsten/Pettigrew] |
| 18750 | Using possible worlds for knowledge and morality may be a step too far [Horsten/Pettigrew] |
| 4898 | Possible worlds are indices for a language, or concrete realities, or abstract possibilities [Perry] |
| 12904 | If varieties of myself can be conceived of as distinct from me, then they are not me [Leibniz] |
| 11981 | If someone's life went differently, then that would be another individual [Leibniz] |
| 12905 | I cannot think my non-existence, nor exist without being myself [Leibniz] |
| 19334 | I can't just know myself to be a substance; I must distinguish myself from others, which is hard [Leibniz] |
| 5033 | Nothing should be taken as certain without foundations [Leibniz] |
| 12913 | Nature is explained by mathematics and mechanism, but the laws rest on metaphysics [Leibniz] |
| 13089 | To fully conceive the subject is to explain the resulting predicates and events [Leibniz] |
| 5034 | Mind is a thinking substance which can know God and eternal truths [Leibniz] |
| 4887 | We try to cause other things to occur by causing mental events to occur [Perry] |
| 5032 | It seems probable that animals have souls, but not consciousness [Leibniz] |
| 4884 | Brain states must be in my head, and yet the pain seems to be in my hand [Perry] |
| 4888 | It seems plausible that many animals have experiences without knowing about them [Perry] |
| 5031 | Everything which happens is not necessary, but is certain after God chooses this universe [Leibniz] |
| 4891 | If epiphenomenalism just says mental events are effects but not causes, it is consistent with physicalism [Perry] |
| 4900 | Prior to Kripke, the mind-brain identity theory usually claimed that the identity was contingent [Perry] |
| 4892 | If physicalists stick with identity (not supervenience), Martian pain will not be like ours [Perry] |
| 4889 | Although we may classify ideas by content, we individuate them differently, as their content can change [Perry] |
| 4896 | The intension of an expression is a function from possible worlds to an appropriate extension [Perry] |
| 12911 | Concepts are what unite a proposition [Leibniz] |
| 4897 | A proposition is a set of possible worlds for which its intension delivers truth [Perry] |
| 4890 | A sharp analytic/synthetic line can rarely be drawn, but some concepts are central to thought [Perry] |
| 12925 | Beauty increases with familiarity [Leibniz] |
| 12927 | Happiness is advancement towards perfection [Leibniz] |
| 15955 | I think the corpuscular theory, rather than forms or qualities, best explains particular phenomena [Leibniz] |
| 12907 | Each possible world contains its own laws, reflected in the possible individuals of that world [Leibniz] |
| 12924 | Motion alone is relative, but force is real, and establishes its subject [Leibniz] |
| 12909 | Everything, even miracles, belongs to order [Leibniz] |
| 5030 | Miracles are extraordinary operations by God, but are nevertheless part of his design [Leibniz] |
| 12912 | Immortality without memory is useless [Leibniz] |
| 12917 | The soul is indestructible and always self-aware [Leibniz] |
| 12918 | Animals have souls, but lack consciousness [Leibniz] |