17 ideas
| 23269 | Philosophy must start from clearly observed facts [Galen] |
| Full Idea: True philosophers concern themselves first and foremost to take clearly observed facts as their point of departure. | |
| From: Galen (The soul's dependence on the body [c.170], Kiv.11.817) | |
| A reaction: I love this one, especially the desire that the facts be 'clearly observed'. That, thank goodness, eliminates quantum mechanics. If you don't love history and the physical sciences, you are not a philosopher. Oh, and reliable gossip. |
| 18739 | Three stages of philosophical logic: syntactic (1905-55), possible worlds (1963-85), widening (1990-) [Horsten/Pettigrew] |
| Full Idea: Three periods can be distinguished in philosophical logic: the syntactic stage, from Russell's definite descriptions to the 1950s, the dominance of possible world semantics from the 50s to 80s, and a current widening of the subject. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 1) | |
| A reaction: [compressed] I've read elsewhere that the arrival of Tarski's account of truth in 1933, taking things beyond the syntactic, was also a landmark. |
| 18741 | Logical formalization makes concepts precise, and also shows their interrelation [Horsten/Pettigrew] |
| Full Idea: Logical formalization forces the investigator to make the central philosophical concepts precise. It can also show how some philosophical concepts and objects can be defined in terms of others. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 2) | |
| A reaction: This is the main rationale of the highly formal and mathematical approach to such things. The downside is when you impose 'precision' on language that was never intended to be precise. |
| 18744 | Models are sets with functions and relations, and truth built up from the components [Horsten/Pettigrew] |
| Full Idea: A (logical) model is a set with functions and relations defined on it that specify the denotation of the non-logical vocabulary. A series of recursive clauses explicate how truth values of complex sentences are compositionally determined from the parts. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 3) | |
| A reaction: See the ideas on 'Functions in logic' and 'Relations in logic' (in the alphabetical list) to expand this important idea. |
| 18740 | If 'exist' doesn't express a property, we can hardly ask for its essence [Horsten/Pettigrew] |
| Full Idea: If there is indeed no property of existence that is expressed by the word 'exist', then it makes no sense to ask for its essence. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 2) | |
| A reaction: As far as I can tell, this was exactly Aristotle's conclusion, so he skirted round the question of 'being qua being', and focused on the nature of objects instead. Grand continental talk of 'Being' doesn't sound very interesting. |
| 18745 | A Tarskian model can be seen as a possible state of affairs [Horsten/Pettigrew] |
| Full Idea: A Tarskian model can in a sense be seen as a model of a possible state of affairs. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 3) | |
| A reaction: I include this remark to show how possible worlds semantics built on the arrival of model theory. |
| 18747 | The 'spheres model' was added to possible worlds, to cope with counterfactuals [Horsten/Pettigrew] |
| Full Idea: The notion of a possible worlds model was extended (resulting in the concept of a 'spheres model') in order to obtain a satisfactory logical treatment of counterfactual conditional sentences. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 4) | |
| A reaction: Thus we add 'centred' worlds, and an 'actual' world, to the loose original model. It is important to remember when we discuss 'close' worlds that we are then committed to these presuppositions. |
| 18748 | Epistemic logic introduced impossible worlds [Horsten/Pettigrew] |
| Full Idea: The idea of 'impossible worlds' was introduced into epistemic logic. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 4) | |
| A reaction: Nathan Salmon seems interested in their role in metaphysics (presumably in relation to Meinongian impossible objects, like circular squares, which must necessarily be circular). |
| 18746 | Possible worlds models contain sets of possible worlds; this is a large metaphysical commitment [Horsten/Pettigrew] |
| Full Idea: Each possible worlds model contains a set of possible worlds. For this reason, possible worlds semantics is often charged with smuggling in heavy metaphysical commitments. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 3) | |
| A reaction: To a beginner it looks very odd that you should try to explain possibility by constructing a model of it in terms of 'possible' worlds. |
| 18750 | Using possible worlds for knowledge and morality may be a step too far [Horsten/Pettigrew] |
| Full Idea: When the possible worlds semantics were further extended to model notions of knowledge and of moral obligation, the application was beginning to look distinctly forced and artificial. | |
| From: Horsten,L/Pettigrew,R (Mathematical Methods in Philosophy [2014], 5) | |
| A reaction: They accept lots of successes in modelling necessity and time. |
| 23266 | The spirit in the soul wants freedom, power and honour [Galen] |
| Full Idea: The spirited part of the soul is desiderative of freedom, victory, power, authority, reputation, and honour. | |
| From: Galen (The soul's dependence on the body [c.170], Kiv.2.772) | |
| A reaction: This is the concept of 'thumos' [spirit], taken straight from Plato's tripartite account of the soul, in 'Republic'. Note that it includes a desire for freedom (in an age of slavery). |
| 23219 | Stopping the heart doesn't terminate activity; pressing the brain does that [Galen, by Cobb] |
| Full Idea: Even when an animals heart was stopped [by hand] it continued its muted whimpers, …but when the brain was pressed the animal stopped making a noise and became unconscious. | |
| From: report of Galen (The soul's dependence on the body [c.170]) by Matthew Cobb - The Idea of the Brain 1 | |
| A reaction: It's not that the ancients didn't do science. It's that ancient people paid no attention to what their scientists discovered. |
| 23264 | Philosophers think faculties are in substances, and invent a faculty for every activity [Galen] |
| Full Idea: Philosophers conceive of faculties as things which inhabit 'substances' much as we inhabit houses, not realising that causes of events are conceived in relational terms. We therefore attribute as many faculties to a substance as activities. | |
| From: Galen (The soul's dependence on the body [c.170], Kiv.2.769) | |
| A reaction: This seems to demolish speculative faculties, but they were revived during the Enlightenment. I am happy to talk of 'philosophical faculties' where they are presumed to originate a type of thought, without commitment to any neuroscience. |
| 23220 | The brain contains memory and reason, and is the source of sensation and decision [Galen] |
| Full Idea: The brain is the principal organ of the psychical members. For within the brain is seated memory, reason and intellect, and from the brain is distributed the power, sensation and voluntary motion. | |
| From: Galen (The soul's dependence on the body [c.170]), quoted by Matthew Cobb - The Idea of the Brain 1 | |
| A reaction: [not sure of ref] Interesting that he assigns the whole of mind to the brain, and not just some aspect of it. He had done experiments. Understanding the role of the brain was amazingly slow. Impeded by religion, I guess. |
| 23265 | The rational part of the soul is the desire for truth, understanding and recollection [Galen] |
| Full Idea: That part of the soul which we call rational is desiderative: …it desires truth, knowledge, learning, understanding, and recollection - in short, all the good things. | |
| From: Galen (The soul's dependence on the body [c.170], Kiv.2.772) | |
| A reaction: Truth is no surprise, but recollection is. Note the separation of knowledge from understanding. This is a very good characterisation of rationality. For the Greeks it has a moral dimension, of wanting what is good. |
| 23268 | We execute irredeemable people, to protect ourselves, as a deterrent, and ending a bad life [Galen] |
| Full Idea: We kill the irredeemably wicked, for three reasons: that they may no longer harm us; as a deterrent to others like them; and because it is actually better from their own point of view to die, when their souls are so damaged they cannot be improved. | |
| From: Galen (The soul's dependence on the body [c.170], Kiv.11.816) | |
| A reaction: The third one sounds like a dubious rationalisation, given that the prisoner probably disagrees. Nowadays we are not so quick to judge someone as irredeemable. The first one works when they run wild, but not after their capture. |
| 19035 | General Relativity allows substantivalism about space-time - that it has independent properties [Hoefer] |
| Full Idea: General Relativity describes space-time in a way that allows it to exist with determinate properties not reducible to the properties and relations of its material contents. Hence nearly all physicists and philosophers writing on GR are substantivalists. | |
| From: Carl Hoefer (The Metaphysics of Space-Time Substantivalism [1996], p.5), quoted by Barbara Vetter - Potentiality 7.3 | |
| A reaction: I'm encouraged by this, as I instinctly favour substantivalism. Imagine removing all the objects from space-time, one by one. What happens as you approach the end of the task? Once they are removed, can they be replaced? |