27 ideas
| 6021 | It is only when we say a proposition that we speak truly or falsely [Sext.Empiricus] |
| Full Idea: It is only when we say a proposition that we speak truly or falsely. | |
| From: Sextus Empiricus (Against the Professors (six books) [c.180], 8.74) | |
| A reaction: This makes assertions truth-bearers, rather than propositions. But a proposition can be true or false if it is stamped with a date and/or place. "Shakespeare was born in Stratford on 23rd April 1664". No one needs to assert that. |
| 6020 | 'Man is a rational mortal animal' is equivalent to 'if something is a man, that thing is a rational mortal animal' [Sext.Empiricus] |
| Full Idea: Definitions are identical to universal propositions in meaning, and only differ in syntax, for whoever says 'Man is a rational mortal animal' says the same thing in meaning as whoever says 'If something is a man, that thing is a rational mortal animal'. | |
| From: Sextus Empiricus (Against the Professors (six books) [c.180], 11.8) | |
| A reaction: How strikingly like Bertrand Russell's interest and solutions. Sextus shows a straightforward interest in logical form, of a kind we associate with the twentieth century. Did Sextus Empiricus invent quantification? |
| 13076 | Scholastics treat relations as two separate predicates of the relata [Cover/O'Leary-Hawthorne] |
| Full Idea: The scholastics treated it as a step in the right explanatory direction to analyze a relational statement of the form 'aRb' into two subject-predicate statements, attributing different relational predicates to a and to b. | |
| From: Cover,J/O'Leary-Hawthorne,J (Substance and Individuation in Leibniz [1999], 2.2.1) | |
| A reaction: The only alternative seems to be Russell's view of relations as pure universals, having a life of their own, quite apart from their relata. Or you could take them as properties of space, time (and powers?), external to the relata? |
| 13102 | If you individuate things by their origin, you still have to individuate the origins themselves [Cover/O'Leary-Hawthorne] |
| Full Idea: If we go for the necessity-of-origins view, A and B are different if the origin of A is different from the origin of B. But one is left with the further question 'When is the origin of A distinct from the origin of B?' | |
| From: Cover,J/O'Leary-Hawthorne,J (Substance and Individuation in Leibniz [1999], 7.4.1) | |
| A reaction: There may be an answer to this, in a regress of origins that support one another, but in the end the objection is obviously good. You can't begin to refer to an 'origin' if you can't identify anything in the first place. |
| 13103 | Numerical difference is a symmetrical notion, unlike proper individuation [Cover/O'Leary-Hawthorne] |
| Full Idea: Scholastics distinguished criteria of numerical difference from questions of individuation proper, since numerical difference is a symmetrical notion. | |
| From: Cover,J/O'Leary-Hawthorne,J (Substance and Individuation in Leibniz [1999], 7.4.1) | |
| A reaction: This apparently old-fashioned point appears to be conclusively correct. Modern thinkers, though, aren't comfortable with proper individuation, because they don't believe in concepts like 'essence' and 'substance' that are needed for the job. |
| 13104 | Haecceity as property, or as colourless thisness, or as singleton set [Cover/O'Leary-Hawthorne] |
| Full Idea: There is a contemporary property construal of haecceities, ...and a Scotistic construal as primitive, 'colourless' thisnesses which, unlike singleton-set haecceities, are aimed to do some explanatory work. | |
| From: Cover,J/O'Leary-Hawthorne,J (Substance and Individuation in Leibniz [1999], 7.4.4) | |
| A reaction: [He associates the contemporary account with David Kaplan] I suppose I would say that individuation is done by properties, but not by some single property, so I take it that I don't believe in haecceities at all. What individuates a haecceity? |
| 13100 | Maybe 'substance' is more of a mass-noun than a count-noun [Cover/O'Leary-Hawthorne] |
| Full Idea: We could think of 'substance' on the model of a mass noun, rather than a count noun. | |
| From: Cover,J/O'Leary-Hawthorne,J (Substance and Individuation in Leibniz [1999], 7.3) | |
| A reaction: They offer this to help Leibniz out of a mess, but I think he would be appalled. The proposal seems close to 'prime matter' in Aristotle, which never quite does the job required of it. The idea is nice, though, and should be taken seriously. |
| 13068 | We can ask for the nature of substance, about type of substance, and about individual substances [Cover/O'Leary-Hawthorne] |
| Full Idea: In the 'blueprint' approach to substance, we confront at least three questions: What is it for a thing to be an individual substance? What is it for a thing to be the kind of substance that it is? What is it to be that very individual substance? | |
| From: Cover,J/O'Leary-Hawthorne,J (Substance and Individuation in Leibniz [1999], 1.1.1) | |
| A reaction: My working view is that the answer to the first question is that substance is essence, that the second question is overrated and parasitic on the third, and that the third is the key question, and also reduces to essence. |
| 13069 | The general assumption is that substances cannot possibly be non-substances [Cover/O'Leary-Hawthorne] |
| Full Idea: There is a widespread assumption, now and in the past, that substances are essentially substances: nothing is actually a substance but possibly a non-substance. | |
| From: Cover,J/O'Leary-Hawthorne,J (Substance and Individuation in Leibniz [1999], 1.1.2) | |
| A reaction: It seems to me that they clearly mean, in this context, that substances are 'necessarily' substances, not that they are 'essentially' substances. I would just say that substances are essences, and leave the necessity question open. |
| 13072 | Modern essences are sets of essential predicate-functions [Cover/O'Leary-Hawthorne] |
| Full Idea: The modern view of essence is that the essence of a particular thing is given by the set of predicate-functions essential to it, and the essence of any kind is given by the set of predicate-functions essential to every possible member of that kind. | |
| From: Cover,J/O'Leary-Hawthorne,J (Substance and Individuation in Leibniz [1999], 1.2.2) | |
| A reaction: Thus the modern view has elided the meanings of 'essential' and 'necessary' when talking of properties. They are said to be 'functions' from possible worlds to individuals. The old view (and mine) demands real essences, not necessary properties. |
| 17080 | Modern essentialists express essence as functions from worlds to extensions for predicates [Cover/O'Leary-Hawthorne] |
| Full Idea: The modern essentialist gives the same metaphysical treatment to every grammatical predicate - by associating a function from worlds to extensions for each. | |
| From: Cover,J/O'Leary-Hawthorne,J (Substance and Individuation in Leibniz [1999], 2.2) | |
| A reaction: I take this to mean that essentialism is the view that if some predicate attaches to an object then that predicate is essential if there is an extension of that predicate in all possible worlds. In English, essential predicates are necessary predicates. |
| 13101 | Necessity-of-origin won't distinguish ex nihilo creations, or things sharing an origin [Cover/O'Leary-Hawthorne] |
| Full Idea: A necessity-of-origins approach cannot work to distinguish things that come into being genuinely ex nihilo, and cannot work to distinguish things sharing a single origin. | |
| From: Cover,J/O'Leary-Hawthorne,J (Substance and Individuation in Leibniz [1999], 7.4.1) | |
| A reaction: Since I am deeply suspicious of essentiality or necessity of origin (and they are not, I presume, the same thing) I like these two. Twins have always bothered me with the second case (where order of birth seems irrelevant). |
| 13081 | Even extreme modal realists might allow transworld identity for abstract objects [Cover/O'Leary-Hawthorne] |
| Full Idea: It might be suggested that even the extreme modal realist can countenance transworld identity for abstract objects. | |
| From: Cover,J/O'Leary-Hawthorne,J (Substance and Individuation in Leibniz [1999], 3.2.2 n46) | |
| A reaction: This may sound right for uncontroversial or well-defined abstracta such as numbers and circles, but even 'or' is ambiguous, and heaven knows what the transworld identity of 'democracy' is! |
| 6026 | How can you investigate without some preconception of your object? [Sext.Empiricus] |
| Full Idea: A preconception and conception must precede every object of investigation, for how can anyone even investigate without some conception of the object of investigation? | |
| From: Sextus Empiricus (Against the Professors (six books) [c.180], 8.331a) | |
| A reaction: The Duhem-Quine thesis about the 'theory-ladenness of observation' is just a revival of some routine ancient scepticism. As well as a conceptual scheme to accommodate the observation, there must also be some motivation for the investigation. |
| 7621 | Special relativity, unlike general relativity, was operationalist in spirit [Putnam on Einstein] |
| Full Idea: Einstein's interpretation of special relativity was operationalist in spirit (in marked contrast to the interpretation he gave to general relativity). | |
| From: comment on Albert Einstein (works [1915]) by Hilary Putnam - Reason, Truth and History Ch.5 | |
| A reaction: The late twentieth century was polluted with daft relativism, and I hold Einstein partly responsible, suspecting that he was a bad philosopher. The later development of Einstein's view noted here is interesting. |
| 13071 | We can go beyond mere causal explanations if we believe in an 'order of being' [Cover/O'Leary-Hawthorne] |
| Full Idea: The philosopher comfortable with an 'order of being' has richer resources to make sense of the 'in virtue of' relation than that provided only by causal relations between states of affairs, positing in addition other sorts of explanatory relationships. | |
| From: Cover,J/O'Leary-Hawthorne,J (Substance and Individuation in Leibniz [1999], 1.1.2) | |
| A reaction: This might best be characterised as 'ontological dependence', and could be seen as a non-causal but fundamental explanatory relationship, and not one that has to depend on a theistic world view. |
| 6032 | Right actions, once done, are those with a reasonable justification [Sext.Empiricus] |
| Full Idea: Right action is whatever, once it has been done, has a reasonable justification. | |
| From: Sextus Empiricus (Against the Professors (six books) [c.180], 7.158) | |
| A reaction: Why does he add 'once it has been done'? Wouldn't a proposed action be right if it had a reasonable justification? This grows out of the classical and Stoic emphasis on reason in ethics, and leads towards Scanlon's Contractualism. |
| 1517 | The tektraktys (1+2+3+4=10) is the 'fount of ever-flowing nature' [Sext.Empiricus] |
| Full Idea: The tektraktys (1+2+3+4=10) is the 'fount of ever-flowing nature', because nature is a harmony of three concords (4th,5th and octave), and these ratios (4:3, 3:2, and 2:1) are found in the tektraktys. | |
| From: Sextus Empiricus (Against the Professors (six books) [c.180], 7.95) |
| 22955 | Einstein took causation to be the bedrock of physics [Einstein, by Coveney/Highfield] |
| Full Idea: It is difficult to overplay Einstein's commitment to the concept of causality as the bedrock of physics. | |
| From: report of Albert Einstein (works [1915]) by P Coveney / R Highfield - The Arrow of Time 3 'problem' | |
| A reaction: I normally avoid arguments from authority, but this carries a bit of weight (e.g. when Russell tries to oppose it). What happens to Einstein's theories if you remove causation from them? |
| 20638 | General relativity assumes laws of nature are the same in all frames of reference [Einstein, by Close] |
| Full Idea: Einstein came to general relativity from the principles that the laws of nature are the same in all frames of reference. | |
| From: report of Albert Einstein (works [1915]) by Frank Close - Theories of Everything 5 'Cosmological' | |
| A reaction: I wish physicists would tell us a bit more about the ontological status of the 'laws of nature'. Presumably they are not supernatural, so there is an aspect of nature which is constant in all frames of reference. Explanation please. |
| 20636 | Newton is a special case of Einstein's general theory, with an infinite speed of light [Einstein, by Close] |
| Full Idea: Einstein's general relativity included Newton's theory as a special case: Newton's theory corresponds to the speed of light being infinite relative to the speed of the interacting bodies. | |
| From: report of Albert Einstein (works [1915]) by Frank Close - Theories of Everything 5 'Gravity' | |
| A reaction: So Newton's theory was NOT wrong, but he made the false assumption that the speed of light was infinite. |
| 21230 | The theory is 'special' because it sticks to observers moving straight, at constant speeds [Einstein, by Farmelo] |
| Full Idea: Einstein's first theory is 'special' because it only deals with observers who move in a straight line at constant speeds with respect to one another. | |
| From: report of Albert Einstein (works [1915]) by Graham Farmelo - The Strangest Man 03 | |
| A reaction: Most theories of this period seem to have focused on the simplest cases, for obvious reasons. |
| 21231 | Assume the speed of light is constant for all observers, and the laws of physics are the same [Einstein, by Farmelo] |
| Full Idea: Einstein assumed that when each observer measures the speed of light in a vacuum, they find the same value, regardless of their speed; and that measurements will lead to agreement on the laws of physics. | |
| From: report of Albert Einstein (works [1915]) by Graham Farmelo - The Strangest Man 03 | |
| A reaction: So are the laws of physics constant for all observers, irrespective of their speed? |
| 20634 | General Relativity says there is no absolute force or acceleration [Einstein, by Close] |
| Full Idea: Einstein's General Theory arose from the idea that there is no absolute measure of force and acceleration. | |
| From: report of Albert Einstein (works [1915]) by Frank Close - Theories of Everything 5 'Gravity' | |
| A reaction: If absolutely everything is only true relative to something else you wonder what the point of measuring anything is. How big can a 'frame of reference' or 'inertial frame' be. Is the multiverse a frame of reference? |
| 20648 | Mass is a measure of energy content [Einstein] |
| Full Idea: The mass of a body is the measure of its energy content. | |
| From: Albert Einstein (works [1915]), quoted by Peter Watson - Convergence 04 'Intro' | |
| A reaction: If I knew what energy was, this would be very illuminating. This idea is e=mc^2 in words. We now have the Higgs field to consider when trying to understand mass. |
| 21232 | Space-time arises from the connection between measurements of space and of time [Einstein, by Farmelo] |
| Full Idea: Einstein noted that the measurements of space and time are not independent but inextricably linked, leading to the idea of unified space-time (introduced by his former teacher Minkowski). | |
| From: report of Albert Einstein (works [1915]) by Graham Farmelo - The Strangest Man 03 | |
| A reaction: Notice the instrumentalist assumptions behind this. |
| 7626 | I do not believe in a personal God [Einstein] |
| Full Idea: I do not believe in a personal God and I have never denied this but have expressed it clearly. | |
| From: Albert Einstein (works [1915]), quoted by Richard Dawkins - The God Delusion Ch.1.15 | |
| A reaction: This is an important corrective to those who claim Einstein as religious, on the basis of remarks about God not playing dice etc. See the whole of Dawkins's chapter on Einstein for full discussion. |