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19463
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Induction assumes some uniformity in nature, or that in some respects the future is like the past [Ayer]
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Full Idea:
In all inductive reasoning we make the assumption that there is a measure of uniformity in nature; or, roughly speaking, that the future will, in the appropriate respects, resemble the past.
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From:
A.J. Ayer (The Problem of Knowledge [1956], 2.viii)
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A reaction:
I would say that nature is 'stable'. Nature changes, so a global assumption of total uniformity is daft. Do we need some global uniformity assumptions, if the induction involved is local? I would say yes. Are all inductions conditional on this?
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9967
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'Impure' sets have a concrete member, while 'pure' (abstract) sets do not [Jubien]
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Full Idea:
Any set with a concrete member is 'impure'. 'Pure' sets are those that are not impure, and are paradigm cases of abstract entities, such as the sort of sets apparently dealt with in Zermelo-Fraenkel (ZF) set theory.
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From:
Michael Jubien (Ontology and Mathematical Truth [1977], p.116)
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A reaction:
[I am unclear whether Jubien is introducing this distinction] This seems crucial in accounts of mathematics. On the one had arithmetic can be built from Millian pebbles, giving impure sets, while logicists build it from pure sets.
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19459
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To say 'I am not thinking' must be false, but it might have been true, so it isn't self-contradictory [Ayer]
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Full Idea:
To say 'I am not thinking' is self-stultifying since if it is said intelligently it must be false: but it is not self-contradictory. The proof that it is not self-contradictory is that it might have been false.
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From:
A.J. Ayer (The Problem of Knowledge [1956], 2.iii)
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A reaction:
If it doesn't imply a contradiction, then it is not a necessary truth, which is what it is normally taken to be. Is 'This is a sentence' necessarily true? It might not have been one, if the rules of English syntax changed recently.
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19460
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'I know I exist' has no counterevidence, so it may be meaningless [Ayer]
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Full Idea:
If there is no experience at all of finding out that one is not conscious, or that one does not exist, ..it is tempting to say that sentences like 'I exist', 'I am conscious', 'I know that I exist' do not express genuine propositions.
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From:
A.J. Ayer (The Problem of Knowledge [1956], 2.iii)
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A reaction:
This is, of course, an application of the somewhat discredited verification principle, but the fact that strictly speaking the principle has been sort of refuted does not mean that we should not take it seriously, and be influenced by it.
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19462
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Induction passes from particular facts to other particulars, or to general laws, non-deductively [Ayer]
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Full Idea:
Inductive reasoning covers all cases in which we pass from a particular statement of fact, or set of them, to a factual conclusion which they do not formally entail. The inference may be to a general law, or by analogy to another particular instance.
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From:
A.J. Ayer (The Problem of Knowledge [1956], 2.viii)
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A reaction:
My preferred definition is 'learning from experience' - which I take to be the most rational behaviour you could possibly imagine. I don't think a definition should be couched in terms of 'objects' or 'particulars'.
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8412
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A causal interaction is when two processes intersect, and correlated modifications persist afterwards [Salmon]
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Full Idea:
When two processes intersect, and they undergo correlated modifications which persist after the intersection, I shall say that the intersection is a causal interaction. I take this as a fundamental causal concept.
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From:
Wesley Salmon (Causality: Production and Propagation [1980], §4)
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A reaction:
There may be a problem individuating processes, just as there is for events. I like this approach to causation, which is ontologically sparse, and fits in with the scientific worldview. Change of properties sounds precise, but isn't. Stick to processes.
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8413
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Cause must come first in propagations of causal interactions, but interactions are simultaneous [Salmon]
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Full Idea:
In a typical cause-effect situation (a 'propagation') cause must precede effect, for propagation over a finite time interval is an essential feature. In an 'interaction', an intersection of processes resulting in change, we have simultaneity.
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From:
Wesley Salmon (Causality: Production and Propagation [1980], §8)
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A reaction:
This takes the direction of time as axiomatic, and quite right too. Salmon isn't addressing the real difficulty, though, which is that the resultant laws are usually held to be time-reversible, which is a bit of a puzzle.
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8411
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Instead of localised events, I take enduring and extended processes as basic to causation [Salmon]
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Full Idea:
I propose to approach causality by taking processes rather than events as basic entities. Events are relatively localised in space and time, while processes have much greater temporal duration, and, in many cases, much greater spatial extent.
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From:
Wesley Salmon (Causality: Production and Propagation [1980], §2)
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A reaction:
This strikes me as an incredibly promising proposal, not just in our understanding of causation, but for our general metaphysics and understanding of nature. See Idea 4931, for example. Vague events and processes blend into one another.
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