### Ideas of Frank P. Ramsey, by Theme

#### [British, 1903 - 1930, Cambridge University. Exceptional philosopher who died very young]

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###### 3. Truth / H. Deflationary Truth / 1. Redundant Truth
 3750 "It is true that x" means no more than x Full Idea: It is evident that "It is true that Caesar was murdered" means no more than that Caesar was murdered. From: Frank P. Ramsey (Facts and Propositions [1927]) A reaction: At the very least, saying it is true adds emphasis. One sentence is about Caesar, the other about a proposal concerning Caesar, so they can't quite be the same. Note Frege's priority in making this suggestion.
###### 4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / f. Axiom of Infinity V
 13430 Infinity: there is an infinity of distinguishable individuals Full Idea: The Axiom of Infinity means that there are an infinity of distinguishable individuals, which is an empirical proposition. From: Frank P. Ramsey (The Foundations of Mathematics [1925], §5) A reaction: The Axiom sounds absurd, as a part of a logical system, but Ramsey ends up defending it. Logical tautologies, which seem to be obviously true, are rendered absurd if they don't refer to any objects, and some of them refer to infinities of objects.
###### 4. Formal Logic / F. Set Theory ST / 4. Axioms for Sets / p. Axiom of Reducibility
 13428 Reducibility: to every non-elementary function there is an equivalent elementary function Full Idea: The Axiom of Reducibility asserted that to every non-elementary function there is an equivalent elementary function [note: two functions are equivalent when the same arguments render them both true or both false]. From: Frank P. Ramsey (The Foundations of Mathematics [1925], §2) A reaction: Ramsey in the business of showing that this axiom from Russell and Whitehead is not needed. He says that the axiom seems to be needed for induction and for Dedekind cuts. Since the cuts rest on it, and it is weak, Ramsey says it must go.
###### 5. Theory of Logic / D. Assumptions for Logic / 4. Identity in Logic
 13427 Either 'a = b' vacuously names the same thing, or absurdly names different things Full Idea: In 'a = b' either 'a' and 'b' are names of the same thing, in which case the proposition says nothing, or of different things, in which case it is absurd. In neither case is it an assertion of a fact; it only asserts when a or b are descriptions. From: Frank P. Ramsey (The Foundations of Mathematics [1925], §1) A reaction: This is essentially Frege's problem with Hesperus and Phosphorus. How can identities be informative? So 2+2=4 is extensionally vacuous, but informative because they are different descriptions.
 13334 Contradictions are either purely logical or mathematical, or they involved thought and language Full Idea: Group A consists of contradictions which would occur in a logical or mathematical system, involving terms such as class or number. Group B contradictions are not purely logical, and contain some reference to thought, language or symbolism. From: Frank P. Ramsey (The Foundations of Mathematics [1925], p.171), quoted by Graham Priest - The Structure of Paradoxes of Self-Reference 1 A reaction: This has become the orthodox division of all paradoxes, but the division is challenged by Priest (Idea 13373). He suggests that we now realise (post-Tarski?) that language is more involved in logic and mathematics than we thought.
###### 6. Mathematics / C. Sources of Mathematics / 6. Logicism / b. Type theory
 6409 The 'simple theory of types' distinguishes levels among properties Full Idea: The idea that there should be something like a distinction of levels among properties is captured in Ramsey's 'simple theory of types'. From: report of Frank P. Ramsey (works [1928]) by A.C. Grayling - Russell A reaction: I merely report this, though it is not immediately obvious how anyone would decide which 'level' a type belonged on.
###### 6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
 13426 Formalists neglect content, but the logicists have focused on generalizations, and neglected form Full Idea: The formalists neglected the content altogether and made mathematics meaningless, but the logicians neglected the form and made mathematics consist of any true generalisations; only by taking account of both sides can we obtain an adequate theory. From: Frank P. Ramsey (The Foundations of Mathematics [1925], §1) A reaction: He says mathematics is 'tautological generalizations'. It is a criticism of modern structuralism that it overemphasises form, and fails to pay attention to the meaning of the concepts which stand at the 'nodes' of the structure.
###### 6. Mathematics / C. Sources of Mathematics / 7. Formalism
 13425 Formalism is hopeless, because it focuses on propositions and ignores concepts Full Idea: The hopelessly inadequate formalist theory is, to some extent, the result of considering only the propositions of mathematics and neglecting the analysis of its concepts. From: Frank P. Ramsey (The Foundations of Mathematics [1925], §1) A reaction: You'll have to read Ramsey to see how this thought pans out, but it at least gives a pointer to how to go about addressing the question.
###### 8. Modes of Existence / D. Universals / 1. Universals
 8495 The distinction between particulars and universals is a mistake made because of language Full Idea: The whole theory of particulars and universals is due to mistaking for a fundamental characteristic of reality what is merely a characteristic of language. From: Frank P. Ramsey (Universals [1925], p.13) A reaction: [Fraser MacBride has pursued this idea] It is rather difficult to deny the existence of particulars, in the sense of actual objects, so this appears to make Ramsey a straightforward nominalist, of some sort or other.
 8493 We could make universals collections of particulars, or particulars collections of their qualities Full Idea: The two obvious methods of abolishing the distinction between particulars and universals are by holding either that universals are collections of particulars, or that particulars are collections of their qualities. From: Frank P. Ramsey (Universals [1925], p.8) A reaction: Ramsey proposes an error theory, arising out of language. Quine seems to offer another attempt, making objects and predication unanalysable and basic. Abstract reference seems to make the strongest claim to separate out the universals.
###### 8. Modes of Existence / E. Nominalism / 1. Nominalism / a. Nominalism
 8494 Obviously 'Socrates is wise' and 'Socrates has wisdom' express the same fact Full Idea: It seems to me as clear as anything can be in philosophy that the two sentences 'Socrates is wise' and 'wisdom is a characteristic of Socrates' assert the same fact and express the same proposition. From: Frank P. Ramsey (Universals [1925], p.12) A reaction: Could be challenged. One says Socrates is just the way he is, the other says he is attached to an abstract entity greater than himself. The squabble over universals has become a squabble over logical form. Finding logical form needs metaphysics!
###### 10. Modality / B. Possibility / 8. Conditionals / d. Non-truthfunction conditionals
 13766 'If' is the same as 'given that', so the degrees of belief should conform to probability theory Full Idea: Ramsey suggested that 'if', 'given that' and 'on the supposition that' come to the same thing, and that the degrees of belief in the antecedent should then conform to probability theory. From: Frank P. Ramsey (Truth and Probability [1926]), quoted by Frank P. Ramsey - Law and Causality B A reaction: [compressed]
 10993 Ramsey's Test: believe the consequent if you believe the antecedent Full Idea: Ramsey's Test for conditionals is that a conditional should be believed if a belief in its antecedent would commit one to believing its consequent. From: report of Frank P. Ramsey (Law and Causality [1928]) by Stephen Read - Thinking About Logic Ch.3 A reaction: A rather pragmatic approach to conditionals
###### 10. Modality / B. Possibility / 8. Conditionals / e. Supposition conditionals
 14279 Asking 'If p, will q?' when p is uncertain, then first add p hypothetically to your knowledge Full Idea: If two people are arguing 'If p, will q?' and are both in doubt as to p, they are adding p hypothetically to their stock of knowledge, and arguing on that basis about q; ...they are fixing their degrees of belief in q given p. From: Frank P. Ramsey (Law and Causality [1928], B 155 n) A reaction: This has become famous as the 'Ramsey Test'. Bennett emphasises that he is not saying that you should actually believe p - you are just trying it for size. The presupposition approach to conditionals seems attractive. Edgington likes 'degrees'.
###### 11. Knowledge Aims / A. Knowledge / 4. Belief / c. Aim of beliefs
 3212 Beliefs are maps by which we steer Full Idea: Beliefs are maps by which we steer. From: Frank P. Ramsey (works [1928]), quoted by Georges Rey - Contemporary Philosophy of Mind p.259 n5
###### 11. Knowledge Aims / A. Knowledge / 4. Belief / d. Cause of beliefs
 22328 I just confront the evidence, and let it act on me Full Idea: I can but put the evidence before me, and let it act on my mind. From: Frank P. Ramsey (The Foundations of Mathematics [1925], p.202), quoted by Michael Potter - The Rise of Analytic Philosophy 1879-1930 70 'Deg' A reaction: Potter calls this observation 'downbeat', but I am an enthusiastic fan. It is roughly my view of both concept formation and of knowledge. You soak up the world, and respond appropriately. The trick is in the selection of evidence to confront.
###### 13. Knowledge Criteria / C. External Justification / 3. Reliabilism / a. Reliable knowledge
 22325 A belief is knowledge if it is true, certain and obtained by a reliable process Full Idea: I have always said that a belief was knowledge if it was 1) true, ii) certain, iii) obtained by a reliable process. From: Frank P. Ramsey (The Foundations of Mathematics [1925], p.258), quoted by Michael Potter - The Rise of Analytic Philosophy 1879-1930 66 'Rel' A reaction: Not sure why it has to be 'certain' as well as 'true'. It seems that 'true' is objective, and 'certain' subjective. I think I know lots of things of which I am not fully certain. Reliabilism long preceded Alvin Goldman.
 19724 Belief is knowledge if it is true, certain, and obtained by a reliable process Full Idea: I have always said that a belief was knowledge if it was (i) true, (ii) certain, (iii) obtained by a reliable process. From: Frank P. Ramsey (Knowledge [1929]), quoted by Juan Comesaņa - Reliabilism 2 A reaction: Remarkable to be addressing the Gettier problem at that date, but Russell had flirted with the problem. Ramsey says the production of the belief must be reliable, rather than the justification for the belief. Note that he wants certainty.
###### 14. Science / B. Scientific Theories / 8. Ramsey Sentences
 6894 Mental terms can be replaced in a sentence by a variable and an existential quantifier Full Idea: Ramsey Sentences are his technique for eliminating theoretical terms in science (and can be applied to mental terms, or to social rights); a term in a sentence is replaced by a variable and an existential quantifier. From: Frank P. Ramsey (Law and Causality [1928]), quoted by Thomas Mautner - Penguin Dictionary of Philosophy p.469 A reaction: The technique is used by functionalists and results in a sort of eliminativism. The intrinsic nature of mental states is eliminated, because everything worth saying can be expressed in terms of functional/causal role. Sounds wrong to me.
###### 14. Science / C. Induction / 6. Bayes's Theorem
 19143 Ramsey gave axioms for an uncertain agent to decide their preferences Full Idea: Ramsey gave an axiomatic treatment of preference in the face of uncertainty, when applied to a particular agent. From: report of Frank P. Ramsey (Truth and Probability [1926]) by Donald Davidson - Truth and Predication 2 A reaction: This is evidently the beginnings of Bayesian decision theory.
###### 19. Language / A. Nature of Meaning / 7. Meaning Holism / c. Meaning by Role
 18818 Sentence meaning is given by the actions to which it would lead Full Idea: The meaning of a sentence is to be defined by reference to the actions to which asserting it would lead. From: Frank P. Ramsey (Facts and Propositions [1927], p.51), quoted by Ian Rumfitt - The Boundary Stones of Thought A reaction: I find this idea quite bizarre. Most sentences have no connection to any action or behavior at all. Do we have to ingeniously contrive some possible action? That is the worst sort of behaviourism. See context - Ramsey wasn't stupid!
###### 26. Natural Theory / D. Laws of Nature / 4. Regularities / b. Best system theory
 9418 All knowledge needs systematizing, and the axioms would be the laws of nature Full Idea: Even if we knew everything, we should still want to systematize our knowledge as a deductive system, and the general axioms in that system would be the fundamental laws of nature. From: Frank P. Ramsey (Law and Causality [1928], §A) A reaction: This is the Mill-Ramsey-Lewis view. Cf. Idea 9420.
 9420 Causal laws result from the simplest axioms of a complete deductive system Full Idea: Causal laws are consequences of those propositions which we should take as axioms if we knew everything and organized it as simply as possible in a deductive system. From: Frank P. Ramsey (Law and Causality [1928], §B) A reaction: Cf. Idea 9418.