Pattern-chaser wrote: ↑December 5th, 2021, 8:38 am
Consul wrote: ↑December 4th, 2021, 3:55 pm
If "speculation" means "conjecture" or "surmise", then sound deductive or inductive arguments are non-speculative!
From the Stanford article on Abduction, that you linked:
Stanford Encyclopedia of Philosophy wrote:Abduction is normally thought of as being one of three major types of inference, the other two being deduction and induction. The distinction between deduction, on the one hand, and induction and abduction, on the other hand, corresponds to the distinction between necessary and non-necessary inferences. In deductive inferences, what is inferred is necessarily true if the premises from which it is inferred are true; that is, the truth of the premises guarantees the truth of the conclusion.
This says what I said in my last post, but worded better, and with the authority of Stanford behind it.
Yes, deduction is the only sort of inference where given the truth of the premises, the probability that the conclusion is true is 1, which means that its truth is logically certain. There is no logical certainty in the case of induction or abduction. Inductive reasoning is probable reasoning; but if an inductive conclusion is true with a very high degree of probability, I wouldn't call it speculative—as opposed to abductive conclusions, where there is no objectively quantifiable probabilistic relationship between the premises and the conclusion.
QUOTE>
"In a
deductively valid inference, it is impossible for the premises to be true and the conclusion false. In an
inductively strong inference, it is improbable (to some degree) that the conclusion is false given that the premises are true. In an
abductively weighty inference, it is implausible that the premises are true and the conclusion is false. The abductive type of inference tends to be the weakest of the three kinds. A conclusion drawn by abductive inference is an intelligent guess. But it is still a guess, because it is tied to an incomplete body of evidence. As new evidence comes in, the guess could be shown to be wrong. Logicians have tended to be not very welcoming in allowing abductive inference as part of logic, because logic is supposed to be an exact science, and abductive inference appears to be inexact. Certainly it is not final. It can be described as a form of guessing. It is subject to being overturned by further evidence in a case. It would seem to be more fallible and conjectural than the other two types of inference." (p. 143)
"
Plausible. To say something is plausible means that it seems to be true. A more specific definition was proposed by Carneades of Cyrene. According to this definition, a proposition is plausible if it seems to be true, and (even more plausible) if it is consistent with other propositions that seem to be true, and (even more plausible) if it is tested, and passes the test. A plausible inference is one that can be drawn from the given apparent facts in a case suggesting a particular conclusion that seems to be true. Both a proposition and its negation can be plausible, as the ancient legal case of the stronger and the weaker man showed." (p. 166)
(Walton, Douglas N. "Abductive, Presumptive and Plausible Arguments."
Informal Logic 21/2 (2001): 141–169.)
———
"Prior probabilities represent the degree to which a hypothesis H_i is supported by non-evidential plausibility considerations,
prior to taking the evidence into account. The notion of
priority for
prior probabilities isn’t temporal – it might make better sense to call them
non-evidential probabilities. Though
non-evidential, the plausibility considerations that inform values for
priors may not be purely
a priori. They may include both conceptual and broadly empirical considerations not captured by the
likelihoods.
Because plausibility assessments are usually less objective than likelihoods, critics sometimes brand
priors as merely subjective, and take their role in the evaluation of hypotheses to be highly problematic. But plausibility assessments often play a crucial role in the sciences, especially when evidence is insufficient to distinguish among some alternative hypotheses. Furthermore, the epithet
‘merely subjective’ is unwarranted. Plausibility assessments are often backed by extensive arguments that draw on forceful conceptual and empirical considerations not captured by likelihoods. That’s the epistemic role of the thought experiment, for example.
Indeed, we often have good reasons, besides the evidence, to strongly reject some
logically possible alternatives as
just too implausible, or as, at least,
much less plausible than better conceived candidates. In evaluating hypotheses, we often bring such considerations to bear, at least implicitly. For, given any hypothesis, logicians can always cook up numerous alternatives that agree with it on all the evidence available thus far. Any reasonable scientist will reject most such inventions immediately, because they look
ad hoc, contrived or plain foolish. Such reasons for rejection appeal to neither purely logical characteristics of these hypotheses, nor to evidence. All such reasons are ‘mere’ plausibility assessments, not part of the evidential likelihoods.
Prior plausibilities are ‘subjective’ in the sense that scientists may disagree on the relative merits of plausibility arguments, and so disagree on the values for priors. Furthermore, the plausibility of a hypothesis is usually somewhat vague or imprecise. So it’s reasonable to represent priors by an interval of values, a
plausibility range, rather than by specific numbers. …The main point is that plausibility assessments in the sciences are far from
mere subjective whims. They play an important role in the epistemology of the sciences. So it’s a virtue of Bayesian confirmation theory that it provides a place for such assessments to figure into the logic of hypothesis evaluation."
(Hawthorne, James. "Bayesian Confirmation Theory." In
The Continuum Companion to the Philosophy of Science, edited by Steven French and Juha Saatsi, 197-217. London: Continuum, 2011. pp. 203-4)
<QUOTE
Unfortunately:
QUOTE>
"[P]lausibility is very much in the eye of the beholder[.]"
(Lowe, E. J.
Personal Agency: The Metaphysics of Mind and Action. Oxford: Oxford University Press, 2008. p. 77)
<QUOTE
- Therefor, as of now, consciousness is out of the realm of science and is in the realm of fantasy and mysticism 
