Popper and Hypothetico-deductivism
Section snippets
Enthymemes and Their Deductivist Reconstructions
Deductivists deem ampliative reasoning invalid. If most reasoning is ampliative, then deductivists deem most reasoning invalid. That unpleasant consequence may seem reason enough to reject deductivism. To be sure, logic has a critical function. The task of the logician is not just to describe or ‘model’ how people do in fact reason, but also to prescribe how people ought to reason if they are to reason well. But if most reasoning is ampliative, then deductivists seem committed to the view that
‘Automobile Logic’
To see how puzzling it is, suppose somebody produces the following argument:
American cars are better than Japanese cars.
Therefore, Cadillacs are better than Japanese cars.
What to say of this argument? You might quarrel with the premise, or with the conclusion, or with both. But what to say if you are a logician? Obviously, if you are a deductive logician, you will say that the argument is invalid, that the conclusion does not follow from the premise.
That verdict may seem a bit harsh. You might
Formal and Semantic Validity
Suppose somebody produces the following argument:
Herbert is a bachelor.
Therefore, he is unhappy.
This argument is invalid. As before, deductivists will treat it as an enthymeme with a missing premise to the effect that bachelors are unhappy, to obtain:
[Bachelors are unhappy.]
Herbert is a bachelor.
Therefore, he is unhappy.
This argument is valid, and has a dubious hypothesis about the virtues of matrimony as its missing premise. As with automobile logic, we would think ill of a philosopher who
Historical Interlude: Mill Versus Aristotle
As we all know, deductive logic was founded by Aristotle, who worked out the logic of categorical propositions and the theory of the syllogism. Aristotle found out that there were 256 possible syllogisms that folk might use, and determined that only 24 of these were valid. So precious were these valid syllogisms that each was given its own name, and in the 13th century Pope John XXI put all their names into a rhyme. Thereafter every educated person had to learn the rhyme and remember the valid
Wittgensteinian Instrumentalism
Mill inaugurated the view that general hypotheses are not premises of our arguments, but rules by which we infer particulars from particulars. The logical positivists said the same thing. They read in Wittgenstein's Tractatus (1921):
Suppose I am given all elementary propositions: then I can simply ask what propositions I can construct out of them. And then I have all propositions, and that fixes their limits. (4.51)
A proposition is a truth-function of elementary propositions. (5)
All
‘Logic of Discovery’ — Deductive or Inductive?
The distinction between the contexts of discovery and justification is due to the logical positivists and Popper. They were sceptical about there being any logic of discovery. They regarded the ‘context of discovery’ as belonging to the province of psychology rather than logic. Popper famously declared (1959: 31): “The initial stage, the act of conceiving or inventing a theory, seems to me to neither call for logical analysis nor to be susceptible of it”. That this statement occurs in a book
‘Logic of Justification’ — Deductive or Inductive?
People reason or argue not just to arrive at new beliefs, or to invent new hypotheses. People also argue for what they believe, reason in order to give reasons for what they believe. In short, people reason or argue to show that they know stuff. Knowledge is not the same as belief, not even the same as true belief — knowledge is justified true belief. People reason or argue to justify their beliefs.
Seen from this perspective, deductive arguments are sadly lacking. To be sure, in a valid
Getting Started — ‘Foundational Beliefs’
In discussing induction, I talked of evidence and evidence-transcending hypotheses. And in discussing abduction and IBE, I talked of having ‘facts’ that require explanation. What is the source of this evidence or of these facts? There are two main sources, sense-experience and testimony. Justificationism bedevils discussion of these matters, too.
My nose itches and I scratch it. The itch causes (or helps cause) the scratching. The itch is also a reason for the scratching (or part of the reason).
References (0)
Cited by (15)
Logic and Reasoning in Crime Analysis
2015, Applied Crime Analysis: A Social Science Approach to Understanding Crime, Criminals, and VictimsConstructs, inferences, and mental measurement
2013, New Ideas in PsychologyCitation Excerpt :Furthermore, it is unnecessary for any theory to contain more than required to explain relevant phenomena and be consistent with other, already accepted, conclusions. Hence, the process of producing viable theories is first and foremost a process of reasoning from phenomena, that is, of inference (Catton, 2004; Haig, 2009; & Musgrave, 2009) and only secondarily, in the absence of sufficient information and only ever in part if at all, one of imaginative construction. An inference from the phenomena requires an adequate conception of the character of phenomena.
In pursuit of formaldehyde: Causally explanatory models and falsification
2011, Studies in History and Philosophy of Science Part C :Studies in History and Philosophy of Biological and Biomedical SciencesHeuristic Philosophy of Mathematics
2022, Synthese Library