23 ideas
| 9331 | How do we determine which of the sentences containing a term comprise its definition? [Horwich] |
| Full Idea: How are we to determine which of the sentences containing a term comprise its definition? | |
| From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §2) | |
| A reaction: Nice question. If I say 'philosophy is the love of wisdom' and 'philosophy bores me', why should one be part of its definition and the other not? What if I stipulated that the second one is part of my definition, and the first one isn't? |
| 21110 | An understanding of the most basic physics should explain all of the subject's mysteries [Krauss] |
| Full Idea: Once we understood the fundamental laws that govern forces of nature at its smallest scales, all of these current mysteries would be revealed as natural consequences of these laws. | |
| From: Lawrence M. Krauss (A Universe from Nothing [2012], 08) | |
| A reaction: This expresses the reductionist view within physics itself. Krauss says the discovery that empty space itself contains energy has led to a revision of this view (because that is not part of the forces and particles studied in basic physics). |
| 21105 | In 1676 it was discovered that water is teeming with life [Krauss] |
| Full Idea: Van Leeuwenhoek first stared at a drop of seemingly empty water with a microscope in 1676 and discovered in was teeming with life. | |
| From: Lawrence M. Krauss (A Universe from Nothing [2012], 04) | |
| A reaction: I am convinced that this had a huge influence on Leibniz's concept of monads. He immediately became convinced that it was some sort of life all the way down. He would be have been disappointed by the subsequent chemical reduction of life. |
| 9333 | A priori belief is not necessarily a priori justification, or a priori knowledge [Horwich] |
| Full Idea: It is one thing to believe something a priori and another for this belief to be epistemically justified. The latter is required for a priori knowledge. | |
| From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §8) | |
| A reaction: Personally I would agree with this, because I don't think anything should count as knowledge if it doesn't have supporting reasons, but fans of a priori knowledge presumably think that certain basic facts are just known. They are a priori justified. |
| 9342 | Understanding needs a priori commitment [Horwich] |
| Full Idea: Understanding is itself based on a priori commitment. | |
| From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §12) | |
| A reaction: This sounds plausible, but needs more justification than Horwich offers. This is the sort of New Rationalist idea I associate with Bonjour. The crucial feature of the New lot is, I take it, their fallibilism. All understanding is provisional. |
| 9332 | Meaning is generated by a priori commitment to truth, not the other way around [Horwich] |
| Full Idea: Our a priori commitment to certain sentences is not really explained by our knowledge of a word's meaning. It is the other way around. We accept a priori that the sentences are true, and thereby provide it with meaning. | |
| From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §8) | |
| A reaction: This sounds like a lovely trump card, but how on earth do you decide that a sentence is true if you don't know what it means? Personally I would take it that we are committed to the truth of a proposition, before we have a sentence for it. |
| 9341 | Meanings and concepts cannot give a priori knowledge, because they may be unacceptable [Horwich] |
| Full Idea: A priori knowledge of logic and mathematics cannot derive from meanings or concepts, because someone may possess such concepts, and yet disagree with us about them. | |
| From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §12) | |
| A reaction: A good argument. The thing to focus on is not whether such ideas are a priori, but whether they are knowledge. I think we should employ the word 'intuition' for a priori candidates for knowledge, and demand further justification for actual knowledge. |
| 9334 | If we stipulate the meaning of 'number' to make Hume's Principle true, we first need Hume's Principle [Horwich] |
| Full Idea: If we stipulate the meaning of 'the number of x's' so that it makes Hume's Principle true, we must accept Hume's Principle. But a precondition for this stipulation is that Hume's Principle be accepted a priori. | |
| From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §9) | |
| A reaction: Yet another modern Quinean argument that all attempts at defining things are circular. I am beginning to think that the only a priori knowledge we have is of when a group of ideas is coherent. Calling it 'intuition' might be more accurate. |
| 9339 | A priori knowledge (e.g. classical logic) may derive from the innate structure of our minds [Horwich] |
| Full Idea: One potential source of a priori knowledge is the innate structure of our minds. We might, for example, have an a priori commitment to classical logic. | |
| From: Paul Horwich (Stipulation, Meaning and Apriority [2000], §11) | |
| A reaction: Horwich points out that to be knowledge it must also say that we ought to believe it. I'm wondering whether if we divided the whole territory of the a priori up into intuitions and then coherent justifications, the whole problem would go away. |
| 5662 | Maybe induction could never prove the existence of something unobservable [Ayer] |
| Full Idea: Some people hold that no inductive argument can give us any reason to believe in the existence of something which could not even in principle be observed. | |
| From: A.J. Ayer (The Concept of a Person [1963], §I) | |
| A reaction: I see nothing illogical in inferring the existence of a poltergeist from the recurrent flight of objects around my lounge. Only an excessive empiricism (which used to afflict Ayer) could lead to this claim. |
| 5664 | Consciousness must involve a subject, and only bodies identify subjects [Ayer] |
| Full Idea: It may not make sense to talk of states of consciousness except as the experiences of some conscious subject; and it may well be that this conscious subject can not be identified except by reference to his body. | |
| From: A.J. Ayer (The Concept of a Person [1963], §IV) | |
| A reaction: It strikes me that Ayer deserves more credit as a pioneer of this view. It tracks back to what may turn out to be the key difficulty for Descartes - how do you individuate a mental substance? I may identify me, but how do I identify you? |
| 5668 | People own conscious states because they are causally related to the identifying body [Ayer] |
| Full Idea: I think personal identity depends on the identity of the body, and that a person's ownership of states of consciousness consists in their standing in a special causal relation to the body by which he is identified. | |
| From: A.J. Ayer (The Concept of a Person [1963], §IV) | |
| A reaction: I think with this is right, with the slight reservation that Ayer talks as if there were two things which have a causal relationship, implying that the link is contingent. Better to think of the whole thing as a single causal network. |
| 5661 | We identify experiences by their owners, so we can't define owners by their experiences [Ayer] |
| Full Idea: Normally we identify experiences in terms of the persons whose experiences they are; but this will lead to a vicious circle if persons themselves are to be analysed in terms of their experiences. | |
| From: A.J. Ayer (The Concept of a Person [1963], §I) | |
| A reaction: This (from a leading empiricist) is a nice basic challenge to all empiricist accounts of personal identity. One might respond my saying that the circle is not vicious. There are two interlinked concepts (experience and persons), like day and night. |
| 5665 | Memory is the best proposal as what unites bundles of experiences [Ayer] |
| Full Idea: The most promising suggestion is that the bundles are tied together by means of memory. | |
| From: A.J. Ayer (The Concept of a Person [1963], §IV) | |
| A reaction: This is interesting for showing how Locke was essentially trying to meet (in advance) Hume's 'bundle' scepticism. Hume proposed associations as the unifying factor, instead of memories. Ayer proposes concepts as a candidate. |
| 5666 | Not all exerience can be remembered, as this would produce an infinite regress [Ayer] |
| Full Idea: Not every experience can be remembered; otherwise each piece of remembering, which is itself an experience, would have to be remembered, and each remembering of a remembering and so ad infinitum. | |
| From: A.J. Ayer (The Concept of a Person [1963], §IV) | |
| A reaction: See Idea 5667. Ayer takes for granted two sorts of consciousness - current awareness, and memory. Ayer brings out a nice difficulty for Locke's proposal, but also draws attention to what may be a very basic misunderstanding about the mind. |
| 5669 | Personal identity can't just be relations of experiences, because the body is needed to identify them [Ayer] |
| Full Idea: A Humean theory, in which a person's identity is made to depend upon relations between experiences ..is not tenable unless the experiences themselves can be identified, and that is only possible through their association with the body. | |
| From: A.J. Ayer (The Concept of a Person [1963], §IV) | |
| A reaction: This seems to me a very fruitful response to difficulties with the 'bundle' view of a person - a better response than the a priori claims of Butler and Reid, or the transcendental argument of Kant. Only a philosopher could ignore the body. |
| 21109 | Space itself can expand (and separate its contents) at faster than light speeds [Krauss] |
| Full Idea: Special Relativity says nothing can travel 'through space' faster than the speed of light. But space itself can do whatever the heck it wants, at least in general relativity. And it can carry distant objects apart from one another at superluminal speeds | |
| From: Lawrence M. Krauss (A Universe from Nothing [2012], 06) | |
| A reaction: Another of my misunderstandings corrected. I assumed that the event horizon (limit of observability) was defined by the stuff retreating at (max) light speed. But beyond that it retreats even faster! What about the photons in space? |
| 21104 | General Relativity: the density of energy and matter determines curvature and gravity [Krauss] |
| Full Idea: The left-hand side of the general relativity equations descrbe the curvature of the universe, and the strength of gravitational forces acting on matter and radiation. The right-hand sides reflect the total density of all kinds of energy and matter. | |
| From: Lawrence M. Krauss (A Universe from Nothing [2012], 04) | |
| A reaction: I had assumed that the equations just described the geometry. In fact the matter determines the nature of the universe in which it exists. Presumably only things with mass get a vote. |
| 21107 | Uncertainty says that energy can be very high over very short time periods [Krauss] |
| Full Idea: The Heisenberg Uncertainty Principle says that the uncertainty in the measured energy of a system is inversely proportional to the length of time over which you observe it. (This allow near infinite energy over very short times). | |
| From: Lawrence M. Krauss (A Universe from Nothing [2012], 04) | |
| A reaction: Apparently this brief energy is 'borrowed', and must be quickly repaid. |
| 21106 | Most of the mass of a proton is the energy in virtual particles (rather than the quarks) [Krauss] |
| Full Idea: The quarks provide very little of the total mass of a proton, and the fields created by the virtual particles contribute most of the energy that goes into the proton's rest energy and, hence, its mass. | |
| From: Lawrence M. Krauss (A Universe from Nothing [2012], 04) | |
| A reaction: He gives an artist's impression of the interior of a proton, which looks like a ship's engine room. |
| 21112 | Empty space contains a continual flux of brief virtual particles [Krauss] |
| Full Idea: Empty space is complicated. It is a boiling brew of virtual particles that pop in and out of existence in a time so short we cannot see them directly. | |
| From: Lawrence M. Krauss (A Universe from Nothing [2012], 10) | |
| A reaction: Apparently the interior of a proton is also like this. This fact gives a foot in the door for explanations of how the Big Bang got started, from these virtual particles. And yet surely space itself only arrives with the Big Bang? |
| 21108 | The universe is precisely 13.72 billion years old [Krauss] |
| Full Idea: We now know the age of the universe to four significant figures. It is 13.72 billion years old! | |
| From: Lawrence M. Krauss (A Universe from Nothing [2012], 05) | |
| A reaction: It amazes me how many people, especially in philosophy, would be reluctant to accept that this is a know fact. I'm not accepting its certainty, but an assertion like this from a leading figure is good enough for me, and it should be for you. |
| 21111 | It seems likely that cosmic inflation is eternal, and this would make a multiverse inevitable [Krauss] |
| Full Idea: A multiverse is inevitable if inflation is eternal, and eternal inflation is by far the most likely possibility in most, if not all, inflationary scenarios. | |
| From: Lawrence M. Krauss (A Universe from Nothing [2012], 08) |