Logic: Deductive and Inductive

Name: Logic: Deductive and Inductive
Author: Read, Carveth

Read, Carveth

Logic

§ 4. The ground of probability is experience, then, and, whenever
possible, statistics; which are a kind of induction. It has indeed been
urged that induction is itself based upon probability; that the
subtlety, complexity and secrecy of nature are such, that we are never
quite sure that we fully know even what we have observed; and that, as
for laws, the conditions of the universe at large may at any moment be
completely changed; so that all imperfect inductions, including the law
of causation itself, are only probable. But, clearly, this doctrine
turns upon another ambiguity in the word 'probable.' It may be used in
the sense of 'less than absolutely certain'; and such doubtless is the
condition of all human knowledge, in comparison with the comprehensive
intuition of arch-angels: or it may mean 'less than certain according
to _our_ standard of certainty,' that is, in comparison with the law of
causation and its derivatives.

We may suppose some one to object that "by this relative standard even
empirical laws cannot be called 'only probable' as long as we 'know no
exception to them'; for that is all that can be said for the boasted law
of causation; and that, accordingly, we can frame no fraction to
represent their probability. That 'all swans are white' was at one time,
from this point of view, not probable but certain; though we now know it
to be false. It would have been an indecorum to call it only probable as
long as no other-coloured swan had been discovered; not merely because
the quantity of belief amounted to certainty, but because the number of
events (seeing a swan) and the number of their happenings in a certain
way (being white) were equal, and therefore the evidence amounted to 1
or certainty." But, in fact, such an empirical law is only probable; and
the estimate of its probability must be based on the number of times
that similar laws have been found liable to exceptions. Albinism is of
frequent occurrence; and it is common to find closely allied varieties
of animals differing in colour. Had the evidence been duly weighed, it
could never have seemed more than probable that 'all swans are white.'
But what law, approaching the comprehensiveness of the law of causation,
presents any exceptions?

Public-domain text, read in full here on John Shaqi.

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Logic: Deductive and InductiveRead, Carveth

Philosophy

Logic: Deductive and Inductive

Read, Carveth

Logic

§ 4. The ground of probability is experience, then, and, whenever
possible, statistics; which are a kind of induction. It has indeed been
urged that induction is itself based upon probability; that the
subtlety, complexity and secrecy of nature are such, that we are never
quite sure that we fully know even what we have observed; and that, as
for laws, the conditions of the universe at large may at any moment be
completely changed; so that all imperfect inductions, including the law
of causation itself, are only probable. But, clearly, this doctrine
turns upon another ambiguity in the word 'probable.' It may be used in
the sense of 'less than absolutely certain'; and such doubtless is the
condition of all human knowledge, in comparison with the comprehensive
intuition of arch-angels: or it may mean 'less than certain according
to _our_ standard of certainty,' that is, in comparison with the law of
causation and its derivatives.

We may suppose some one to object that "by this relative standard even
empirical laws cannot be called 'only probable' as long as we 'know no
exception to them'; for that is all that can be said for the boasted law
of causation; and that, accordingly, we can frame no fraction to
represent their probability. That 'all swans are white' was at one time,
from this point of view, not probable but certain; though we now know it
to be false. It would have been an indecorum to call it only probable as
long as no other-coloured swan had been discovered; not merely because
the quantity of belief amounted to certainty, but because the number of
events (seeing a swan) and the number of their happenings in a certain
way (being white) were equal, and therefore the evidence amounted to 1
or certainty." But, in fact, such an empirical law is only probable; and
the estimate of its probability must be based on the number of times
that similar laws have been found liable to exceptions. Albinism is of
frequent occurrence; and it is common to find closely allied varieties
of animals differing in colour. Had the evidence been duly weighed, it
could never have seemed more than probable that 'all swans are white.'
But what law, approaching the comprehensiveness of the law of causation,
presents any exceptions?

Public-domain text, read in full here on John Shaqi.

Logic: Deductive and Inductive

Logic: Deductive and Inductive

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