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All the ideas for 'Structures and Structuralism in Phil of Maths', 'Letters to Thomas Burnett' and 'Leviathan'

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59 ideas

1. Philosophy / F. Analytic Philosophy / 2. Analysis by Division
Resolve a complex into simple elements, then reconstruct the complex by using them [Hobbes, by MacIntyre]
     Full Idea: Hobbes took his method from Galileo, of resolving any complex situation into its logically primitive, simple elements and then using the simple elements to show how the complex situation could be reconstructed.
     From: report of Thomas Hobbes (Leviathan [1651]) by Alasdair MacIntyre - A Short History of Ethics Ch.10
     A reaction: Reverse engineering of reality. This idea, wherever it comes from, strikes me as the key to the advance of human understanding. No one has yet improved on it as a method, in science or philosophy. Reconstruction needs the mechanism.
3. Truth / F. Semantic Truth / 2. Semantic Truth
While true-in-a-model seems relative, true-in-all-models seems not to be [Reck/Price]
     Full Idea: While truth can be defined in a relative way, as truth in one particular model, a non-relative notion of truth is implied, as truth in all models.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)
     A reaction: [The article is actually discussing arithmetic] This idea strikes me as extremely important. True-in-all-models is usually taken to be tautological, but it does seem to give a more universal notion of truth. See semantic truth, Tarski, Davidson etc etc.
4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / a. Axioms for sets
ZFC set theory has only 'pure' sets, without 'urelements' [Reck/Price]
     Full Idea: In standard ZFC ('Zermelo-Fraenkel with Choice') set theory we deal merely with pure sets, not with additional urelements.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §2)
     A reaction: The 'urelements' would the actual objects that are members of the sets, be they physical or abstract. This idea is crucial to understanding philosophy of mathematics, and especially logicism. Must the sets exist, just as the urelements do?
5. Theory of Logic / G. Quantification / 5. Second-Order Quantification
Three types of variable in second-order logic, for objects, functions, and predicates/sets [Reck/Price]
     Full Idea: In second-order logic there are three kinds of variables, for objects, for functions, and for predicates or sets.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5)
     A reaction: It is interesting that a predicate seems to be the same as a set, which begs rather a lot of questions. For those who dislike second-order logic, there seems nothing instrinsically wicked in having variables ranging over innumerable multi-order types.
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / g. Real numbers
'Analysis' is the theory of the real numbers [Reck/Price]
     Full Idea: 'Analysis' is the theory of the real numbers.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §2)
     A reaction: 'Analysis' began with the infinitesimal calculus, which later built on the concept of 'limit'. A continuum of numbers seems to be required to make that work.
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / a. Axioms for numbers
Mereological arithmetic needs infinite objects, and function definitions [Reck/Price]
     Full Idea: The difficulties for a nominalistic mereological approach to arithmetic is that an infinity of physical objects are needed (space-time points? strokes?), and it must define functions, such as 'successor'.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)
     A reaction: Many ontologically austere accounts of arithmetic are faced with the problem of infinity. The obvious non-platonist response seems to be a modal or if-then approach. To postulate infinite abstract or physical entities so that we can add 3 and 2 is mad.
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / e. Peano arithmetic 2nd-order
Peano Arithmetic can have three second-order axioms, plus '1' and 'successor' [Reck/Price]
     Full Idea: A common formulation of Peano Arithmetic uses 2nd-order logic, the constant '1', and a one-place function 's' ('successor'). Three axioms then give '1 is not a successor', 'different numbers have different successors', and induction.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §2)
     A reaction: This is 'second-order' Peano Arithmetic, though it is at least as common to formulate in first-order terms (only quantifying over objects, not over properties - as is done here in the induction axiom). I like the use of '1' as basic instead of '0'!
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / a. Mathematics is set theory
Set-theory gives a unified and an explicit basis for mathematics [Reck/Price]
     Full Idea: The merits of basing an account of mathematics on set theory are that it allows for a comprehensive unified treatment of many otherwise separate branches of mathematics, and that all assumption, including existence, are explicit in the axioms.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)
     A reaction: I am forming the impression that set-theory provides one rather good model (maybe the best available) for mathematics, but that doesn't mean that mathematics is set-theory. The best map of a landscape isn't a landscape.
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / a. Structuralism
Structuralism emerged from abstract algebra, axioms, and set theory and its structures [Reck/Price]
     Full Idea: Structuralism has emerged from the development of abstract algebra (such as group theory), the creation of axiom systems, the introduction of set theory, and Bourbaki's encyclopaedic survey of set theoretic structures.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §2)
     A reaction: In other words, mathematics has gradually risen from one level of abstraction to the next, so that mathematical entities like points and numbers receive less and less attention, with relationships becoming more prominent.
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / b. Varieties of structuralism
Relativist Structuralism just stipulates one successful model as its arithmetic [Reck/Price]
     Full Idea: Relativist Structuralism simply picks one particular model of axiomatised arithmetic (i.e. one particular interpretation that satisfies the axioms), and then stipulates what the elements, functions and quantifiers refer to.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)
     A reaction: The point is that a successful model can be offered, and it doesn't matter which one, like having any sort of aeroplane, as long as it flies. I don't find this approach congenial, though having a model is good. What is the essence of flight?
There are 'particular' structures, and 'universal' structures (what the former have in common) [Reck/Price]
     Full Idea: The term 'structure' has two uses in the literature, what can be called 'particular structures' (which are particular relational systems), but also what can be called 'universal structures' - what particular systems share, or what they instantiate.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §6)
     A reaction: This is a very helpful distinction, because it clarifies why (rather to my surprise) some structuralists turn out to be platonists in a new guise. Personal my interest in structuralism has been anti-platonist from the start.
Pattern Structuralism studies what isomorphic arithmetic models have in common [Reck/Price]
     Full Idea: According to 'pattern' structuralism, what we study are not the various particular isomorphic models of arithmetic, but something in addition to them: a corresponding pattern.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §7)
     A reaction: Put like that, we have to feel a temptation to wield Ockham's Razor. It's bad enough trying to give the structure of all the isomorphic models, without seeking an even more abstract account of underlying patterns. But patterns connect to minds..
There are Formalist, Relativist, Universalist and Pattern structuralism [Reck/Price]
     Full Idea: There are four main variants of structuralism in the philosophy of mathematics - formalist structuralism, relativist structuralism, universalist structuralism (with modal variants), and pattern structuralism.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §9)
     A reaction: I'm not sure where Chihara's later book fits into this, though it is at the nominalist end of the spectrum. Shapiro and Resnik do patterns (the latter more loosely); Hellman does modal universalism; Quine does the relativist version. Dedekind?
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / c. Nominalist structuralism
Formalist Structuralism says the ontology is vacuous, or formal, or inference relations [Reck/Price]
     Full Idea: Formalist Structuralism endorses structural methodology in mathematics, but rejects semantic and metaphysical problems as either meaningless, or purely formal, or as inference relations.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §3)
     A reaction: [very compressed] I find the third option fairly congenial, certainly in preference to rather platonist accounts of structuralism. One still needs to distinguish the mathematical from the non-mathematical in the inference relations.
Maybe we should talk of an infinity of 'possible' objects, to avoid arithmetic being vacuous [Reck/Price]
     Full Idea: It is tempting to take a modal turn, and quantify over all possible objects, because if there are only a finite number of actual objects, then there are no models (of the right sort) for Peano Arithmetic, and arithmetic is vacuously true.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5)
     A reaction: [compressed; Geoffrey Hellman is the chief champion of this view] The article asks whether we are not still left with the puzzle of whether infinitely many objects are possible, instead of existent.
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / d. Platonist structuralism
Universalist Structuralism is based on generalised if-then claims, not one particular model [Reck/Price]
     Full Idea: Universalist Structuralism is a semantic thesis, that an arithmetical statement asserts a universal if-then statement. We build an if-then statement (using quantifiers) into the structure, and we generalise away from any one particular model.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5)
     A reaction: There remains the question of what is distinctively mathematical about the highly generalised network of inferences that is being described. Presumable the axioms capture that, but why those particular axioms? Russell is cited as an originator.
Universalist Structuralism eliminates the base element, as a variable, which is then quantified out [Reck/Price]
     Full Idea: Universalist Structuralism is eliminativist about abstract objects, in a distinctive form. Instead of treating the base element (say '1') as an ambiguous referring expression (the Relativist approach), it is a variable which is quantified out.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §5)
     A reaction: I am a temperamental eliminativist on this front (and most others) so this is tempting. I am also in love with the concept of a 'variable', which I take to be utterly fundamental to all conceptual thought, even in animals, and not just a trick of algebra.
6. Mathematics / B. Foundations for Mathematics / 7. Mathematical Structuralism / e. Structuralism critique
The existence of an infinite set is assumed by Relativist Structuralism [Reck/Price]
     Full Idea: Relativist Structuralism must first assume the existence of an infinite set, otherwise there would be no model to pick, and arithmetical terms would have no reference.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)
     A reaction: See Idea 10169 for Relativist Structuralism. They point out that ZFC has an Axiom of Infinity.
7. Existence / D. Theories of Reality / 6. Physicalism
Every part of the universe is body, and non-body is not part of it [Hobbes]
     Full Idea: The world is corporeal, that is to say, body...and every part of the universe is body, and that which is not body is no part of the universe.
     From: Thomas Hobbes (Leviathan [1651], IV.46)
     A reaction: [Hobbes concedes existence to visible spirits, but not invisible ones]. This is the kind of remark which got Hobbes hated. It is also the sort of thing that makes him the best candidate for the 'first modern man'.
8. Modes of Existence / E. Nominalism / 6. Mereological Nominalism
A nominalist might avoid abstract objects by just appealing to mereological sums [Reck/Price]
     Full Idea: One way for a nominalist to reject appeal to all abstract objects, including sets, is to only appeal to nominalistically acceptable objects, including mereological sums.
     From: E Reck / M Price (Structures and Structuralism in Phil of Maths [2000], §4)
     A reaction: I'm suddenly thinking that this looks very interesting and might be the way to go. The issue seems to be whether mereological sums should be seen as constrained by nature, or whether they are unrestricted. See Mereology in Ontology...|Intrinsic Identity.
9. Objects / B. Unity of Objects / 2. Substance / a. Substance
The notion of substance is one of the keys to true philosophy [Leibniz]
     Full Idea: I consider the notion of substance to be one of the keys to the true philosophy. ....I imagine that philosophers will one day know the notion of substance a bit better than they do now.
     From: Gottfried Leibniz (Letters to Thomas Burnett [1703], 1699.01.20/30)
     A reaction: This is a controversial remark at this historical moment, when the apparent Aristotelian commitment to substances was becoming discredited. Personally I would eliminate substance, but not just because physicists don't refer to it.
12. Knowledge Sources / B. Perception / 4. Sense Data / a. Sense-data theory
Appearance and reality can be separated by mirrors and echoes [Hobbes]
     Full Idea: If colours or sounds were in the bodies or objects that cause them, they could not be severed from them, as by glasses, and in echoes by reflection, we see they are; where we know the thing we see is in one place, the appearance in another.
     From: Thomas Hobbes (Leviathan [1651], 1.01)
13. Knowledge Criteria / D. Scepticism / 5. Dream Scepticism
Dreams must be false because they seem absurd, but dreams don't see waking as absurd [Hobbes]
     Full Idea: Because waking I often observe the absurdity of dreams, but never dream of the absurdity of my waking thoughts, I am well satisfied that, being awake, I know I dream not, though when I dream I think myself awake.
     From: Thomas Hobbes (Leviathan [1651], 1.02)
16. Persons / F. Free Will / 5. Against Free Will
Freedom is absence of opposition to action; the idea of 'free will' is absurd [Hobbes]
     Full Idea: If a man should talk to me of a 'free-will', or any 'free' but free from being hindered by opposition, I should not say that he were in an error, but that his words were without a meaning, that is to say, absurd.
     From: Thomas Hobbes (Leviathan [1651], 1.05)
16. Persons / F. Free Will / 7. Compatibilism
Liberty and necessity are consistent, as when water freely flows, by necessity [Hobbes]
     Full Idea: Liberty and necessity are consistent: as in the water, that hath not only liberty, but a necessity of descending by the channel.
     From: Thomas Hobbes (Leviathan [1651], II.Ch.XI)
     A reaction: Hume asserts something similar (Idea 2223), but they both miss the point, which is that libertarians about water would have to believe it didn't need to follow gravity, but could refuse to flow. Freedom of will and freedom of action are quite different.
18. Thought / A. Modes of Thought / 3. Emotions / e. Basic emotions
The 'simple passions' are appetite, desire, love, aversion, hate, joy, and grief [Hobbes, by Goldie]
     Full Idea: For Hobbes the 'simple passions' were appetite, desire, love, aversion, hate, joy, and grief.
     From: report of Thomas Hobbes (Leviathan [1651], I.6) by Peter Goldie - The Emotions 4 'Evidence'
     A reaction: This is the standard approach to emotions of Hobbes's time. Modern thinkers probably reject the idea that passions can be simple or basic. Rightly, I think.
20. Action / C. Motives for Action / 1. Acting on Desires
The will is just the last appetite before action [Hobbes]
     Full Idea: In deliberation, the last appetite or aversion immediately adhering to the action, or to the omission thereof, is that we call the Will.
     From: Thomas Hobbes (Leviathan [1651], 1.06)
     A reaction: I share his caution about 'the will', but his observation strikes me as inaccurate. When I drink, my 'will' is not my thirst. I take the will to be a feature of my reason. I gave my thirst permission to indulge itself. The will is practical reason?
20. Action / C. Motives for Action / 3. Acting on Reason / a. Practical reason
Reason is usually general, but deliberation is of particulars [Hobbes]
     Full Idea: Reasoning is in general words, but deliberation for the most part is of particulars.
     From: Thomas Hobbes (Leviathan [1651], 1.06)
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / h. Expressivism
'Good' is just what we desire, and 'Evil' what we hate [Hobbes]
     Full Idea: Whatsoever is the object of any man's appetite or desire, that is it which he for his part calleth 'Good'; and the object of his hate or aversion 'Evil'.
     From: Thomas Hobbes (Leviathan [1651], 1.06)
     A reaction: This meets the Frege-Geach Problem - that we can have these feelings while reading ancient history, but we can't possibly 'desire' any of that. This is better on evil than on good.
22. Metaethics / A. Ethics Foundations / 2. Source of Ethics / j. Ethics by convention
Men's natural desires are no sin, and neither are their actions, until law makes it so [Hobbes]
     Full Idea: The desires and other passions of man are in themselves no sin. No more are the actions that proceed from those passions, till they know a law that forbids them.
     From: Thomas Hobbes (Leviathan [1651], 1.13)
     A reaction: That is a pretty flat rejection of natural law, as you might expect from an empiricist. So prior to the first law-making, no one ever did anything wrong? Hm.
22. Metaethics / B. Value / 2. Values / g. Love
Desire and love are the same, but in the desire the object is absent, and in love it is present [Hobbes]
     Full Idea: Desire and love are the same thing, save that by desire we always signify the absence of the object, by love most commonly the presence of the same.
     From: Thomas Hobbes (Leviathan [1651], 1.06)
     A reaction: Implausible reductivism from Hobbes. Plenty of counterexamples to this. You work it out!
22. Metaethics / B. Value / 2. Values / i. Self-interest
All voluntary acts aim at some good for the doer [Hobbes]
     Full Idea: Of the voluntary acts of every man, the object is some good to himself.
     From: Thomas Hobbes (Leviathan [1651], 1.14)
     A reaction: Nonsense. You can only describe sacrificial acts for loved ones, such as children, in this way if this proposal is a tautology. Hobbes cannot know the truth of this claim.
23. Ethics / B. Contract Ethics / 1. Contractarianism
Hobbes wants a contract to found morality, but shared values are needed to make a contract [MacIntyre on Hobbes]
     Full Idea: Hobbes makes two incompatible demands of the original contract: he wishes it to be the foundation of all shared and common standards and rules; but he also wishes it to be a contract, which needs prior shared and common standards.
     From: comment on Thomas Hobbes (Leviathan [1651], Pt 1) by Alasdair MacIntyre - A Short History of Ethics Ch.10
     A reaction: At the very least, the participants in a contract must be committed to keeping it even when it is not convenient. But a common purpose seems to be needed too, which makes the contract itself intrinsically valuable. Similar objections to Kant.
A contract is a mutual transfer of rights [Hobbes]
     Full Idea: The mutual transferring of right is that which men call 'contract'.
     From: Thomas Hobbes (Leviathan [1651], 1.14)
The person who performs first in a contract is said to 'merit' the return, and is owed it [Hobbes]
     Full Idea: He that performeth first in the case of a contract, is said to 'merit' that which he is to receive by the performance of the other, and he hath it as due.
     From: Thomas Hobbes (Leviathan [1651], 1.14)
23. Ethics / B. Contract Ethics / 2. Golden Rule
For Hobbes the Golden Rule concerns not doing things, whereas Jesus encourages active love [Hobbes, by Flanagan]
     Full Idea: Hobbes put the Golden Rule as 'do NOT do to others what you would NOT want done to yourself'. Jesus's formulation encouraged active love. Most Westerners conceive their moral duty as not to do harm, rather than actively doing good.
     From: report of Thomas Hobbes (Leviathan [1651]) by Owen Flanagan - The Problem of the Soul p.20n
     A reaction: This idea probably runs very deep into western culture, where most people feel that they are being very morally good when they are sitting at home and not actually annoying anyone. Utilitarianism also offers a challenge to such complacency.
23. Ethics / B. Contract Ethics / 3. Promise Keeping
In the violent state of nature, the merest suspicion is enough to justify breaking a contract [Hobbes]
     Full Idea: If a covenant is made with neither party performing presently, but trust one another, in the condition of mere nature (which is war between men) upon reasonable suspicion, it is void.
     From: Thomas Hobbes (Leviathan [1651], 1.14)
23. Ethics / B. Contract Ethics / 4. Value of Authority
Fear of sanctions is the only motive for acceptance of authority that Hobbes can think of [MacIntyre on Hobbes]
     Full Idea: Hobbes has such a limited view of human motives that he cannot provide any other explanation for the acceptance of authority than the fear of sanctions..
     From: comment on Thomas Hobbes (Leviathan [1651], Pt 1) by Alasdair MacIntyre - A Short History of Ethics Ch.10
     A reaction: There are two alternative views - the conservative view that people naturally welcome and even need authority, because they need to be led; or the Aristotelian view that people are naturally communal, and authority is part of community life.
Suspicion will not destroy a contract, if there is a common power to enforce it [Hobbes]
     Full Idea: If there be a common power set over both parties in a contract, with right and force sufficient to compel performance, a contract does not become void as soon as the parties are suspicious.
     From: Thomas Hobbes (Leviathan [1651], 1.14)
23. Ethics / B. Contract Ethics / 5. Free Rider
No one who admitted to not keeping contracts could ever be accepted as a citizen [Hobbes]
     Full Idea: He therefore that breaketh his covenant, and consequently declareth that he thinks he may with reason do so, cannot be received into any society.
     From: Thomas Hobbes (Leviathan [1651], 1.15)
If there is a good reason for breaking a contract, the same reason should have stopped the making of it [Hobbes]
     Full Idea: If any fault of man be sufficient to discharge our covenant made, the same ought in reason to have been sufficient to have hindered the making of it.
     From: Thomas Hobbes (Leviathan [1651], 1.15)
23. Ethics / B. Contract Ethics / 7. Prisoner's Dilemma
The first performer in a contract is handing himself over to an enemy [Hobbes]
     Full Idea: He which performeth first in a contract, does but betray himself to his enemy.
     From: Thomas Hobbes (Leviathan [1651], 1.14)
23. Ethics / B. Contract Ethics / 8. Contract Strategies
Someone who keeps all his contracts when others are breaking them is making himself a prey to others [Hobbes]
     Full Idea: He that should be modest and tractable, and perform all the promises, in such time and place where no man else should do so, should but make himself a prey to others.
     From: Thomas Hobbes (Leviathan [1651], 1.15)
23. Ethics / C. Virtue Theory / 2. Elements of Virtue Theory / c. Motivation for virtue
Virtues are a means to peaceful, sociable and comfortable living [Hobbes]
     Full Idea: The writers of moral philosophy, though they acknowledge the same virtues and vices, yet not seeing wherein consisted their goodness, nor that they come to be praised as the means of peaceable, sociable and comfortable living.
     From: Thomas Hobbes (Leviathan [1651], 1.15)
23. Ethics / C. Virtue Theory / 3. Virtues / c. Justice
Injustice is the failure to keep a contract, and justice is the constant will to give what is owed [Hobbes]
     Full Idea: The definition of 'injustice' is no other than the not performance of covenant….. and 'justice' is the constant will of giving to every man his own.
     From: Thomas Hobbes (Leviathan [1651], 1.15)
24. Political Theory / A. Basis of a State / 1. A People / b. The natural life
In time of war the life of man is solitary, poor, nasty, brutish and short [Hobbes]
     Full Idea: In a time of war…. there is continual fear, and danger of violent death, and the life of man is solitary, poor, nasty, brutish and short.
     From: Thomas Hobbes (Leviathan [1651], 1.13)
Hobbes attributed to savages the passions which arise in a law-bound society [Hobbes, by Rousseau]
     Full Idea: Hobbes had wrongly injected into the savage man's concern for self-preservation the need to satisfy a multitude of passions which are the product of society and which have made laws necessary.
     From: report of Thomas Hobbes (Leviathan [1651]) by Jean-Jacques Rousseau - Discourse on the Origin of Inequality Part I
     A reaction: Hobbes's famous remark concerns a state of war, which is quite a sophisticated state of conflict between well formed social groups. Rousseau's savage is fairly solitary, so won't be involved in war.
24. Political Theory / B. Nature of a State / 2. State Legitimacy / a. Sovereignty
Hobbes says the people voluntarily give up their sovereignty, in a contract with a ruler [Hobbes, by Oksala]
     Full Idea: While Hobbes had held that the people were the final source of political authority, he had argued that in entering the social contract they gave up their sovereignty by transferring all power to an absolute ruler.
     From: report of Thomas Hobbes (Leviathan [1651]) by Johanna Oksala - Political Philosophy: all that matters Ch.5
     A reaction: Later the idea of 'inalienable' rights crept in. If you volunteer for exploitation or slavery, that still doesn't justify them. Sadism is presumably not justified by masochism.
25. Social Practice / B. Equalities / 1. Grounds of equality
There is not enough difference between people for one to claim more benefit than another [Hobbes]
     Full Idea: The difference between man and man is not so considerable as that one man can thereupon claim to himself any benefit to which another may not pretend as well as he.
     From: Thomas Hobbes (Leviathan [1651], 1.13)
Hobbes says people are roughly equal; Locke says there is no right to impose inequality [Hobbes, by Wolff,J]
     Full Idea: Hobbes's principle of equality was a claim about the mental and physical capabilities of all people. For Locke it is a moral claim about rights: no person has a natural right to subordinate any other.
     From: report of Thomas Hobbes (Leviathan [1651]) by Jonathan Wolff - An Introduction to Political Philosophy (Rev) 1 'Locke'
     A reaction: There are obvious questions to ask about the claim that people are naturally equal. For the second one, does the lion have a natural right to subordinate the gazelle? Who cares! I'm inclined to be consequentialist about equality.
25. Social Practice / C. Rights / 3. Alienating rights
If we seek peace and defend ourselves, we must compromise on our rights [Hobbes]
     Full Idea: From the first law of nature (that we seek peace, but also defend ourselves) comes the second: that a man be willing to lay down his rights to all things, and be contented with so much liberty against other men as he would allow other men against himself.
     From: Thomas Hobbes (Leviathan [1651], 1.14)
25. Social Practice / D. Justice / 2. The Law / c. Natural law
We should obey the laws of nature, provided other people are also obeying them [Hobbes, by Wolff,J]
     Full Idea: Hobbes's position is that we have a duty to obey the Laws of Nature when others around us are known (or can reasonably be expected) to be obeying them too, and so our compliance will not be exploited.
     From: report of Thomas Hobbes (Leviathan [1651]) by Jonathan Wolff - An Introduction to Political Philosophy (Rev) 1 'Hobbes'
     A reaction: In particular, we should keep contracts. Hobbes doesn't seem fully committed to keeping facts and values separate.
25. Social Practice / D. Justice / 2. The Law / d. Legal positivism
The legal positivism of Hobbes said law is just formal or procedural [Hobbes, by Jolley]
     Full Idea: Hobbes was one of the first to propose the view known as 'legal positivism' - that the criterion for deciding whether a rule is a genuine law is entirely formal or procedural
     From: report of Thomas Hobbes (Leviathan [1651]) by Nicholas Jolley - Leibniz Ch.7
     A reaction: This was opposed to the tradition of natural law, deriving from Aquinas. It is part of a picture of values draining out of the world as science comes to dominate. The is/ought distinction is its culmination. Power replaces virtue, and Thrasymachus wins.
25. Social Practice / D. Justice / 3. Punishment / a. Right to punish
Punishment should only be for reform or deterrence [Hobbes]
     Full Idea: We are forbidden to inflict punishment with any other design than for correction of the offender, or direction of others.
     From: Thomas Hobbes (Leviathan [1651], 1.15)
25. Social Practice / E. Policies / 2. Religion in Society
If fear of unknown powers is legal it is religion, if it is illegal it is superstition [Hobbes]
     Full Idea: Fear of power invisible, feigned by the mind or imagined from tales publicly allowed, is religion; not allowed, is superstition.
     From: Thomas Hobbes (Leviathan [1651], 1.06)
26. Natural Theory / C. Causation / 9. General Causation / a. Constant conjunction
Causation is only observation of similar events following each other, with nothing visible in between [Hobbes]
     Full Idea: In knowing the meaning of 'causing', men can only observe and remember what they have seen to precede the like effect at some other time, without seeing between the antecedent and subsequent event any dependence or connexion at all.
     From: Thomas Hobbes (Leviathan [1651], 1.12)
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / c. Essence and laws
Gravity is within matter because of its structure, and it can be explained. [Leibniz]
     Full Idea: I believe that both gravity and elasticity are in matter only because of the structure of the system and can be explained mechanically or through impulsion.
     From: Gottfried Leibniz (Letters to Thomas Burnett [1703], 1699 draft)
     A reaction: The significance of this remark is that gravity is held (in full knowledge of Newton's work) to be within matter, and not imposed from the outside. I believe we now postulate a particle as part of the explanation.
29. Religion / D. Religious Issues / 1. Religious Commitment / a. Religious Belief
Religion is built on ignorance and misinterpretation of what is unknown or frightening [Hobbes]
     Full Idea: In these four things - opinion of ghosts, ignorance of second causes, devotion towards what men fear, and taking of things casual for prognostics, consisteth the natural seed of religion.
     From: Thomas Hobbes (Leviathan [1651], 1.12)
29. Religion / D. Religious Issues / 2. Immortality / a. Immortality
Belief in an afterlife is based on poorly founded gossip [Hobbes]
     Full Idea: Knowledge of man's estate after death, and its rewards, is a belief grounded upon other men's sayings that they knew it supernaturally, or they knew those, that knew those, that knew others, that knew it supernaturally.
     From: Thomas Hobbes (Leviathan [1651], 1.15)