31 ideas
| 12124 | Metaphysics is the best knowledge, because it is the simplest [Bacon] |
| Full Idea: That knowledge is worthiest which is charged with least multiplicity, which appeareth to be metaphysic | |
| From: Francis Bacon (The Advancement of Learning [1605], II.VII.6) | |
| A reaction: A surprising view, coming from the father of modern science, but essentially correct. Obviously metaphysics aspires to avoid multiplicity, but it is riddled not only with complexity in its researches, but massive uncertainties. |
| 12123 | Natural history supports physical knowledge, which supports metaphysical knowledge [Bacon] |
| Full Idea: Knowledges are as pyramides, whereof history is the basis. So of natural philosophy, the basis is natural history, the stage next the basis is physic; the stage next the vertical point is metaphysic. | |
| From: Francis Bacon (The Advancement of Learning [1605], II.VII.6) | |
| A reaction: The father of modern science keeps a place for metaphysics, as the most abstract level above the physical sciences. I would say he is right. It leads to my own slogan: science is the servant of philosophy. |
| 12119 | Physics studies transitory matter; metaphysics what is abstracted and necessary [Bacon] |
| Full Idea: Physic should contemplate that which is inherent in matter, and therefore transitory; and metaphysic that which is abstracted and fixed | |
| From: Francis Bacon (The Advancement of Learning [1605], II.VII.3) | |
| A reaction: He cites the ancients for this view, with which he agrees. One could do worse than hang onto metaphysics as the study of necessities, but must then face the attacks of the Quineans - that knowledge of necessities is beyond us. |
| 12120 | Physics is of material and efficient causes, metaphysics of formal and final causes [Bacon] |
| Full Idea: Physic inquireth and handleth the material and efficient causes; and metaphysic handleth the formal and final causes. | |
| From: Francis Bacon (The Advancement of Learning [1605], II.VII.3) | |
| A reaction: Compare Idea 12119. This divides up Aristotle's famous Four Causes (or Explanations), outlined in 'Physics' II.3. The concept of 'matter', and the nature of 'cause' seem to me to fall with the purview of metaphysics. Interesting, though. |
| 10146 | Cantor's theories needed the Axiom of Choice, but it has led to great controversy [Feferman/Feferman] |
| Full Idea: The Axiom of Choice is a pure existence statement, without defining conditions. It was necessary to provide a foundation for Cantor's theory of transfinite cardinals and ordinal numbers, but its nonconstructive character engendered heated controversy. | |
| From: Feferman / Feferman (Alfred Tarski: life and logic [2004], Int I) |
| 10147 | The Axiom of Choice is consistent with the other axioms of set theory [Feferman/Feferman] |
| Full Idea: In 1938 Gödel proved that the Axiom of Choice is consistent with the other axioms of set theory. | |
| From: Feferman / Feferman (Alfred Tarski: life and logic [2004], Int I) | |
| A reaction: Hence people now standardly accept ZFC, rather than just ZF. |
| 10150 | The Trichotomy Principle is equivalent to the Axiom of Choice [Feferman/Feferman] |
| Full Idea: The Trichotomy Principle (any number is less, equal to, or greater than, another number) turned out to be equivalent to the Axiom of Choice. | |
| From: Feferman / Feferman (Alfred Tarski: life and logic [2004], Int I) | |
| A reaction: [He credits Sierpinski (1918) with this discovery] |
| 10148 | Axiom of Choice: a set exists which chooses just one element each of any set of sets [Feferman/Feferman] |
| Full Idea: Zermelo's Axiom of Choice asserts that for any set of non-empty sets that (pairwise) have no elements in common, then there is a set that 'simultaneously chooses' exactly one element from each set. Note that this is an existential claim. | |
| From: Feferman / Feferman (Alfred Tarski: life and logic [2004], Int I) | |
| A reaction: The Axiom is now widely accepted, after much debate in the early years. Even critics of the Axiom turn out to be relying on it. |
| 10149 | Platonist will accept the Axiom of Choice, but others want criteria of selection or definition [Feferman/Feferman] |
| Full Idea: The Axiom of Choice seems clearly true from the Platonistic point of view, independently of how sets may be defined, but is rejected by those who think such existential claims must show how to pick out or define the object claimed to exist. | |
| From: Feferman / Feferman (Alfred Tarski: life and logic [2004], Int I) | |
| A reaction: The typical critics are likely to be intuitionists or formalists, who seek for both rigour and a plausible epistemology in our theory. |
| 10158 | A structure is a 'model' when the axioms are true. So which of the structures are models? [Feferman/Feferman] |
| Full Idea: A structure is said to be a 'model' of an axiom system if each of its axioms is true in the structure (e.g. Euclidean or non-Euclidean geometry). 'Model theory' concerns which structures are models of a given language and axiom system. | |
| From: Feferman / Feferman (Alfred Tarski: life and logic [2004], Int V) | |
| A reaction: This strikes me as the most interesting aspect of mathematical logic, since it concerns the ways in which syntactic proof-systems actually connect with reality. Tarski is the central theoretician here, and his theory of truth is the key. |
| 10162 | Tarski and Vaught established the equivalence relations between first-order structures [Feferman/Feferman] |
| Full Idea: In the late 1950s Tarski and Vaught defined and established basic properties of the relation of elementary equivalence between two structures, which holds when they make true exactly the same first-order sentences. This is fundamental to model theory. | |
| From: Feferman / Feferman (Alfred Tarski: life and logic [2004], Int V) | |
| A reaction: This is isomorphism, which clarifies what a model is by giving identity conditions between two models. Note that it is 'first-order', and presumably founded on classical logic. |
| 10160 | Löwenheim-Skolem says if the sentences are countable, so is the model [Feferman/Feferman] |
| Full Idea: The Löwenheim-Skolem Theorem, the earliest in model theory, states that if a countable set of sentences in a first-order language has a model, then it has a countable model. | |
| From: Feferman / Feferman (Alfred Tarski: life and logic [2004], Int V) | |
| A reaction: There are 'upward' (sentences-to-model) and 'downward' (model-to-sentences) versions of the theory. |
| 10159 | Löwenheim-Skolem Theorem, and Gödel's completeness of first-order logic, the earliest model theory [Feferman/Feferman] |
| Full Idea: Before Tarski's work in the 1930s, the main results in model theory were the Löwenheim-Skolem Theorem, and Gödel's establishment in 1929 of the completeness of the axioms and rules for the classical first-order predicate (or quantificational) calculus. | |
| From: Feferman / Feferman (Alfred Tarski: life and logic [2004], Int V) |
| 10161 | If a sentence holds in every model of a theory, then it is logically derivable from the theory [Feferman/Feferman] |
| Full Idea: Completeness is when, if a sentences holds in every model of a theory, then it is logically derivable from that theory. | |
| From: Feferman / Feferman (Alfred Tarski: life and logic [2004], Int V) |
| 10156 | 'Recursion theory' concerns what can be solved by computing machines [Feferman/Feferman] |
| Full Idea: 'Recursion theory' is the subject of what can and cannot be solved by computing machines | |
| From: Feferman / Feferman (Alfred Tarski: life and logic [2004], Ch.9) | |
| A reaction: This because 'recursion' will grind out a result step-by-step, as long as the steps will 'halt' eventually. |
| 10155 | Both Principia Mathematica and Peano Arithmetic are undecidable [Feferman/Feferman] |
| Full Idea: In 1936 Church showed that Principia Mathematica is undecidable if it is ω-consistent, and a year later Rosser showed that Peano Arithmetic is undecidable, and any consistent extension of it. | |
| From: Feferman / Feferman (Alfred Tarski: life and logic [2004], Int IV) |
| 12121 | We don't assume there is no land, because we can only see sea [Bacon] |
| Full Idea: They are ill discoverers that think there is no land, when they can see nothing but sea. | |
| From: Francis Bacon (The Advancement of Learning [1605], II.VII.5) | |
| A reaction: Just the sort of pithy remark for which Bacon is famous. It is an obvious point, but a nice corrective to anyone who wants to apply empirical principles in a rather gormless way. |
| 12117 | Science moves up and down between inventions of causes, and experiments [Bacon] |
| Full Idea: All true and fruitful natural philosophy hath a double scale or ladder, ascendent and descendent, ascending from experiments to the invention of causes, and descending from causes to the invention of new experiments. | |
| From: Francis Bacon (The Advancement of Learning [1605], II.VII.1) | |
| A reaction: After several hundred years, I doubt whether anyone can come up with a better account of scientific method than Bacon's. |
| 12127 | Many different theories will fit the observed facts [Bacon] |
| Full Idea: The ordinary face and view of experience is many times satisfied by several theories and philosophies. | |
| From: Francis Bacon (The Advancement of Learning [1605], II.VIII.5) | |
| A reaction: He gives as his example that the Copernican system and the Ptolemaic system both seem to satisfy all the facts. He wrote in 1605, just before Galileo's telescope. His point is regularly made in modern discussions. In this case, he was wrong! |
| 12126 | People love (unfortunately) extreme generality, rather than particular knowledge [Bacon] |
| Full Idea: It is the nature of the mind of man (to the extreme prejudice of knowledge) to delight in the spacious liberty of generalities, as in a champaign region, and not in the inclosures of particularity. | |
| From: Francis Bacon (The Advancement of Learning [1605], II.VIII.1) | |
| A reaction: I have to plead guilty to this myself. He may have pinpointed the key motivation behind philosophy. We all want to know things, as Aristotle said, but some of us want the broad brush, and others want the fine detail. |
| 23429 | The environment needs localised politics, with its care for the land [Dobson] |
| Full Idea: More localised politics helps to generate the disposition of care for the land which is a core feature of environmental politics. | |
| From: Andrew Dobson (Environmental Politics: very short intro [2016], 4) | |
| A reaction: I currently live in a time when localised politics is hugely devalued, because centralisation and privatisation are cheaper. It seems obvious that many human needs require a commitment to a particular locality. |
| 23424 | An ideology judges things now, and offers an ideal, with a strategy for reaching it [Dobson] |
| Full Idea: An ideology generally has three components: a judgement (usually critical) of how things are, a picture of the ideology's ideal society, and a strategy for progressing towards the ideal. | |
| From: Andrew Dobson (Environmental Politics: very short intro [2016], 2) | |
| A reaction: Conservatives tend to think we are already living in the ideal, and they reject most ideologies for being 'idealistic' (which presumably means delusional). I'm a fan of ideals, but combined with cool judgement. |
| 23426 | Ecologism is often non-liberal, by claiming to know other people's best interests [Dobson] |
| Full Idea: Liberals say that their preferences are their interests, and resist the idea that anyone could know their interests better than they can. …To this degree, ecologism might be regarded as 'non-liberal'. | |
| From: Andrew Dobson (Environmental Politics: very short intro [2016], 2) | |
| A reaction: There are lots of other cases where liberal citizens may not realise their best interests, such as in the control of traffic, or of drugs. |
| 23427 | Socialism can be productive and centralised, or less productive and decentralised [Dobson] |
| Full Idea: Marx and his heirs promote a productivist socialism, but utopian socialists such as William Morris offer a less productivist and more decentralised form of socialism. | |
| From: Andrew Dobson (Environmental Politics: very short intro [2016], 2) | |
| A reaction: Modern history teaches us to be very cautious about the centralised version. Presumably you could be decentralised but still value production highly, even if it is a bit less efficient. |
| 23428 | Difference feminists say women differ fundamentally from men [Dobson] |
| Full Idea: Difference feminists argue that men and women are fundamentally different. | |
| From: Andrew Dobson (Environmental Politics: very short intro [2016], 2) | |
| A reaction: You can be significantly different without being 'fundamentally' different. Personally I don't see a huge difference, even though history may have greatly exaggerated and dramatised what differences there are. |
| 23422 | For the environment, affluence and technology matter as much as population size [Dobson] |
| Full Idea: Although bare population figures are important for environmental impact, the level of affluence and the technology are also crucial factors. | |
| From: Andrew Dobson (Environmental Politics: very short intro [2016], 2) | |
| A reaction: It is worth noting that the technology can also have a good impact, though affluence is nearly always bad. |
| 23423 | We currently value the present fourteen times more highly than the future [Dobson] |
| Full Idea: At current rates we seem to value present concerns as fourteen times more valuable than future concerns. | |
| From: Andrew Dobson (Environmental Politics: very short intro [2016], 2) | |
| A reaction: A sobering figure, which sounds about right. This directly influences how much we spend on future concerns. One thought is that future generations may be much more affluent than us! |
| 23430 | A million years is a proper unit of political time [Dobson] |
| Full Idea: We must acknowledge that a million years is a proper unit of political time. | |
| From: Andrew Dobson (Environmental Politics: very short intro [2016], 5) | |
| A reaction: [He cites Colin Tudge] Such thinking is almost impossible, but owners of large aristocratic estates seem to have thought in centuries, because they were confident of continuity. The more we identify with all of humanity, the more this is possible. |
| 23425 | Ecologism says growth must be reduced, and efficiency is not enough [Dobson] |
| Full Idea: A central belief of the ideology of ecologism is that aggregate growth must be reduced, and that this is very unlikely to be achieved by efficiency gains alone. | |
| From: Andrew Dobson (Environmental Politics: very short intro [2016], 2) | |
| A reaction: He argues that efficiency gains invariably lead to increased production. Trickle down economics needs huge growth to deliver a good life for the poorest sector. Ecologism has to be fairly egalitarian about wealth. |
| 12125 | Teleological accounts are fine in metaphysics, but they stop us from searching for the causes [Bacon] |
| Full Idea: To say 'leaves are for protecting of fruit', or that 'clouds are for watering the earth', is well inquired and collected in metaphysic, but in physic they are impertinent. They are hindrances, and the search of the physical causes hath been neglected. | |
| From: Francis Bacon (The Advancement of Learning [1605], II.VII.7) | |
| A reaction: This is the standard rebellion against Aristotle which gave rise to the birth of modern science. The story has been complicated by natural selection, which bestows a sort of purpose on living things. Nowadays we pursue both paths. |
| 12118 | Essences are part of first philosophy, but as part of nature, not part of logic [Bacon] |
| Full Idea: I assign to summary philosophy the operation of essences (as quantity, similitude, diversity, possibility), with this distinction - that they be handled as they have efficacy in nature, and not logically. | |
| From: Francis Bacon (The Advancement of Learning [1605], II.VII.3) | |
| A reaction: I take this to be a splendid motto for scientific essentialism, in a climate where modal logicians appear to have taken over the driving seat in our understanding of essences. |