20 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. |
| 8952 | We reach 'reflective equilibrium' when intuitions and theory completely align [Fisher] |
| Full Idea: A state of 'reflective equilibrium' is when our theory and our intuitions become completely aligned | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 12.IV) | |
| A reaction: [Rawls made this concept famous] This is a helpful concept in trying to spell out the ideal which is the dream of believers in 'pure reason' - that there is a goal in which everything comes right. The problem is when people have different intuitions! |
| 8943 | Three-valued logic says excluded middle and non-contradition are not tautologies [Fisher] |
| Full Idea: In three-valued logic (L3), neither the law of excluded middle (p or not-p), nor the law of non-contradiction (not(p and not-p)) will be tautologies. If p has the value 'indeterminate' then so will not-p. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.I) | |
| A reaction: I quite accept that the world is full of indeterminate propositions, and that excluded middle and non-contradiction can sometimes be uncertain, but I am reluctant to accept that what is being offered here should be called 'logic'. |
| 8945 | Fuzzy logic has many truth values, ranging in fractions from 0 to 1 [Fisher] |
| Full Idea: In fuzzy logic objects have properties to a greater or lesser degree, and truth values are given as fractions or decimals, ranging from 0 to 1. Not-p is defined as 1-p, and other formula are defined in terms of maxima and minima for sets. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.II) | |
| A reaction: The question seems to be whether this is actually logic, or a recasting of probability theory. Susan Haack attacks it. If logic is the study of how truth is preserved as we move between propositions, then 0 and 1 need a special status. |
| 8951 | Classical logic is: excluded middle, non-contradiction, contradictions imply all, disjunctive syllogism [Fisher] |
| Full Idea: For simplicity, we can say that 'classical logic' amounts to the truth of four sentences: 1) either p or not-p; 2) it is not the case that both p and not-p; 3) from p and not-p, infer q; 4) from p or q and not-p, infer q. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 12.I) | |
| A reaction: [She says there are many ways of specifying classical logic] Intuition suggests that 2 and 4 are rather hard to dispute, while 1 is ignoring some grey areas, and 3 is totally ridiculous. There is, of course, plenty of support for 3! |
| 8950 | Logic formalizes how we should reason, but it shouldn't determine whether we are realists [Fisher] |
| Full Idea: Even if one is inclined to be a realist about everything, it is hard to see why our logic should be the determiner. Logic is supposed to formalize how we ought to reason, but whether or not we should be realists is a matter of philosophy, not logic. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 09.I) | |
| A reaction: Nice to hear a logician saying this. I do not see why talk in terms of an object is a commitment to its existence. We can discuss the philosopher's stone, or Arthur's sword, or the Loch Ness monster, or gravitinos, with degrees of commitment. |
| 8946 | We could make our intuitions about heaps precise with a million-valued logic [Fisher] |
| Full Idea: We could construct a 1,000,000-valued logic that would allow our intuitions concerning a heap to vary exactly with the amount of sand in the heap. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008]) | |
| A reaction: Presumably only an infinite number of grains of sand would then produce a true heap, and even one grain would count as a bit of a heap, which must both be wrong, so I can't see this helping much. |
| 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. |
| 8944 | Vagueness can involve components (like baldness), or not (like boredom) [Fisher] |
| Full Idea: Vague terms come in at least two different kinds: those whose constituent parts come in discrete packets (bald, rich, red) and those that don't (beauty, boredom, niceness). | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 07.II) | |
| A reaction: The first group seem to be features of the external world, and the second all occur in the mind. Baldness may be vague, but presumably hairs are (on the whole) not. Nature doesn't care whether someone is actually 'bald' or not. |
| 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. |
| 8941 | We can't explain 'possibility' in terms of 'possible' worlds [Fisher] |
| Full Idea: Explaining 'it is possible that p' by saying p is true in at least one possible world doesn't get me very far. If I don't understand what possibility is, then appealing to possible worlds is not going to do me much good. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 06.III) | |
| A reaction: This seems so blatant that I assume friends of possible worlds will have addressed the problem. Note that you will also need to understand 'possible' to define necessity as 'true in all possible worlds'. Necessarily-p is not-possibly-not-p. |
| 8947 | If all truths are implied by a falsehood, then not-p might imply both q and not-q [Fisher] |
| Full Idea: If all truths are implied by a falsehood, then 'if there are no trees in the park then there is no shade' and 'if there are no trees in the park there is plenty of shade' both come out as true. Intuitively, though, the second one is false. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 08.I) | |
| A reaction: The rule that a falsehood implies all truths must be the weakest idea in classical logic, if it actually implies a contradiction. This means we must take an interest in relevance logics. |
| 8949 | In relevance logic, conditionals help information to flow from antecedent to consequent [Fisher] |
| Full Idea: A good account of relevance logic suggests that a conditional will be true when the flow of information is such that a conditional is the device that helps information to flow from the antecedent to the consequent. | |
| From: Jennifer Fisher (On the Philosophy of Logic [2008], 08.III) | |
| A reaction: Hm. 'If you are going out, you'll need an umbrella'. This passes on information about 'out', but also brings in new information. 'If you are going out, I'm leaving you'. What flows is an interpretation of the antecedent. Tricky. |
| 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. |
| 6027 | From the fact that some men die, we cannot infer that they all do [Philodemus] |
| Full Idea: There is no necessary inference, from the fact that men familiar to us die when pierced through the heart, that all men do. | |
| From: Philodemus (On Signs (damaged) [c.50 BCE], 1.3) | |
| A reaction: This is scepticism about the logic of induction, long before David Hume. This is said to be a Stoic argument against Epicureans - though on the whole Stoics are not keen on scepticism. |
| 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. |
| 22241 | Don't fear god or worry about death; the good is easily got and the terrible easily cured [Philodemus] |
| Full Idea: Don't fear god, Don't worry about death; What is good is easy to get, What is terrible is easy to cure. | |
| From: Philodemus (Herculaneum Papyrus [c.50 BCE], 1005,4.9-14) | |
| A reaction: This is known as the Four-Part Cure, and is an epicurean prayer, probably formulated by Epicurus. |