17 ideas
| 22138 | Science rests on scholastic metaphysics, not on Hume, Kant or Carnap [Boulter] |
| Full Idea: The metaphysical principles that allow the scientist to learn from experience are scholastic, not Humean or Kantian or those of twentieth-century positivism. | |
| From: Stephen Boulter (Why Medieval Philosophy Matters [2019], 2) | |
| A reaction: Love this. Most modern philosophers of science would be deeply outraged by this, but I reckon that careful and open-minded interviews with scientists would prove it to be correct. We want to know the essential nature of electrons. |
| 10476 | The idea that groups of concepts could be 'implicitly defined' was abandoned [Hodges,W] |
| Full Idea: Late nineteenth century mathematicians said that, although plus, minus and 0 could not be precisely defined, they could be partially 'implicitly defined' as a group. This nonsense was rejected by Frege and others, as expressed in Russell 1903. | |
| From: Wilfrid Hodges (Model Theory [2005], 2) | |
| A reaction: [compressed] This is helpful in understanding what is going on in Frege's 'Grundlagen'. I won't challenge Hodges's claim that such definitions are nonsense, but there is a case for understanding groups of concepts together. |
| 10478 | Since first-order languages are complete, |= and |- have the same meaning [Hodges,W] |
| Full Idea: In first-order languages the completeness theorem tells us that T |= φ holds if and only if there is a proof of φ from T (T |- φ). Since the two symbols express the same relationship, theorist often just use |- (but only for first-order!). | |
| From: Wilfrid Hodges (Model Theory [2005], 3) | |
| A reaction: [actually no spaces in the symbols] If you are going to study this kind of theory of logic, the first thing you need to do is sort out these symbols, which isn't easy! |
| 10477 | |= in model-theory means 'logical consequence' - it holds in all models [Hodges,W] |
| Full Idea: If every structure which is a model of a set of sentences T is also a model of one of its sentences φ, then this is known as the model-theoretic consequence relation, and is written T |= φ. Not to be confused with |= meaning 'satisfies'. | |
| From: Wilfrid Hodges (Model Theory [2005], 3) | |
| A reaction: See also Idea 10474, which gives the other meaning of |=, as 'satisfies'. The symbol is ALSO used in propositional logical, to mean 'tautologically implies'! Sort your act out, logicians. |
| 10474 | |= should be read as 'is a model for' or 'satisfies' [Hodges,W] |
| Full Idea: The symbol in 'I |= S' reads that if the interpretation I (about word meaning) happens to make the sentence S state something true, then I 'is a model for' S, or I 'satisfies' S. | |
| From: Wilfrid Hodges (Model Theory [2005], 1) | |
| A reaction: Unfortunately this is not the only reading of the symbol |= [no space between | and =!], so care and familiarity are needed, but this is how to read it when dealing with models. See also Idea 10477. |
| 10481 | Models in model theory are structures, not sets of descriptions [Hodges,W] |
| Full Idea: The models in model-theory are structures, but there is also a common use of 'model' to mean a formal theory which describes and explains a phenomenon, or plans to build it. | |
| From: Wilfrid Hodges (Model Theory [2005], 5) | |
| A reaction: Hodges is not at all clear here, but the idea seems to be that model-theory offers a set of objects and rules, where the common usage offers a set of descriptions. Model-theory needs homomorphisms to connect models to things, |
| 10473 | Model theory studies formal or natural language-interpretation using set-theory [Hodges,W] |
| Full Idea: Model theory is the study of the interpretation of any language, formal or natural, by means of set-theoretic structures, with Tarski's truth definition as a paradigm. | |
| From: Wilfrid Hodges (Model Theory [2005], Intro) | |
| A reaction: My attention is caught by the fact that natural languages are included. Might we say that science is model theory for English? That sounds like Quine's persistent message. |
| 10475 | A 'structure' is an interpretation specifying objects and classes of quantification [Hodges,W] |
| Full Idea: A 'structure' in model theory is an interpretation which explains what objects some expressions refer to, and what classes some quantifiers range over. | |
| From: Wilfrid Hodges (Model Theory [2005], 1) | |
| A reaction: He cites as examples 'first-order structures' used in mathematical model theory, and 'Kripke structures' used in model theory for modal logic. A structure is also called a 'universe'. |
| 10480 | First-order logic can't discriminate between one infinite cardinal and another [Hodges,W] |
| Full Idea: First-order logic is hopeless for discriminating between one infinite cardinal and another. | |
| From: Wilfrid Hodges (Model Theory [2005], 4) | |
| A reaction: This seems rather significant, since mathematics largely relies on first-order logic for its metatheory. Personally I'm tempted to Ockham's Razor out all these super-infinities, but mathematicians seem to make use of them. |
| 22134 | Thoughts are general, but the world isn't, so how can we think accurately? [Boulter] |
| Full Idea: Our thoughts are full of generalities, but the world contains no generalities. So how can our thoughts accurately represent the world? This is the problem of universals. | |
| From: Stephen Boulter (Why Medieval Philosophy Matters [2019], 1) | |
| A reaction: I so love it when someone comes up with a really clear explanation of a problem, and this is a beauty from Stephen Boulter. Only a really clear explanation can motivate philosophical issues for non-philosophers. |
| 22150 | Logical possibility needs the concepts of the proposition to be adequate [Boulter] |
| Full Idea: One can only be sure that a proposition expresses a genuine logical possibility if one can be sure that one's concepts are adequate to things referred to in the proposition. | |
| From: Stephen Boulter (Why Medieval Philosophy Matters [2019], 4) | |
| A reaction: Boulter says this is a logical constraint place on logical possibility by the scholastics which tends to be neglected by modern thinkers, who only worry about whether the proposition implies a contradiction. So we now use thought experiments. |
| 22139 | Experiments don't just observe; they look to see what interventions change the natural order [Boulter] |
| Full Idea: Experiments differ from observational studies in that experiments usually involve intervening in some way in the natural order to see if altering something about that order causes a change in the response of that order. | |
| From: Stephen Boulter (Why Medieval Philosophy Matters [2019], 2) | |
| A reaction: Not convinced by this. Lots of experiments isolate a natural process, rather than 'intervening'. Chemists constantly purify substances. Particle accelerators pick out things to accelerate. Does 'intervening' in nature even make sense? |
| 22136 | Science begins with sufficient reason, de-animation, and the importance of nature [Boulter] |
| Full Idea: Three assumptions needed for the emergence of science are central to medieval thought: that the natural order is subject to the principle of sufficient reason, that nature is de-animated, and that it is worthy of study. | |
| From: Stephen Boulter (Why Medieval Philosophy Matters [2019], 2) | |
| A reaction: A very illuminating and convincing observation. Why did Europe produce major science? The answer is likely to be found in Christianity. |
| 22135 | Our concepts can never fully capture reality, but simplification does not falsify [Boulter] |
| Full Idea: While the natural order is richer than our conceptual representations of it, nonetheless our concepts can be adequate to real singulars because simplification is not falsification. | |
| From: Stephen Boulter (Why Medieval Philosophy Matters [2019], 1) | |
| A reaction: I don't know if 'simplification' is one of the faculties I am trying to identify. I suspect it is a common factor among most of our intellectual faculties. I love 'simplification is not falsification'. Vagueness isn't falsification either. |
| 22152 | Aristotelians accept the analytic-synthetic distinction [Boulter] |
| Full Idea: Aristotle and the scholastics accept the analytic/synthetic distinction, but do not take it to be particularly significant. | |
| From: Stephen Boulter (Why Medieval Philosophy Matters [2019], 5) | |
| A reaction: I record this because I'm an Aristotelian, and need to know what I'm supposed to think. Luckily, I accept the distinction. |
| 22156 | The facts about human health are the measure of the values in our lives [Boulter] |
| Full Idea: The objective facts relating to human health broadly construed are the facts that measure the moral value of our actions, policies and institutions. | |
| From: Stephen Boulter (Why Medieval Philosophy Matters [2019], 6) | |
| A reaction: This is the Aristotelian approach to facts and values, which I thoroughly endorse. To say there is nothing instrinsically wrong with being unhealthy is an absurd attitude. |
| 7903 | The six perfections are giving, morality, patience, vigour, meditation, and wisdom [Nagarjuna] |
| Full Idea: The six perfections are of giving, morality, patience, vigour, meditation, and wisdom. | |
| From: Nagarjuna (Mahaprajnaparamitashastra [c.120], 88) | |
| A reaction: What is 'morality', if giving is not part of it? I like patience and vigour being two of the virtues, which immediately implies an Aristotelian mean (which is always what is 'appropriate'). |