Analysis of Mr. Mill's System of Logic — John Stuart Mill — John Shaqi
Analysis of Mr. Mill's System of Logic
John Stuart Mill · en
The aim, in the deductive method, is either to discover the law of the
effect, or to account for it by _explaining_ it, that is, by pointing
out some more general phenomenon (though often less familiar to us) of
which this is a case and a partial exemplification, or some laws of
causation which produce it by their joint or successive action. This
explanation may be made, either--1. By resolving the laws of the complex
effect into its elements, which consist as well of the separate laws of
the causes which share in producing it, as also of their collocation,
i.e. the fact that these separate laws have been so combined; or--2. By
resolving the law which connects two links, not proximate, in a chain of
causation, into the laws which connect each link with the intermediate
links; or--3. By the _subsumption_ or gathering up of several laws under
one which amounts to the sum of them all, and which is the recognition
of the same sequence in different sets of instances. In the first two of
the processes, laws are resolved into others, which both extend to more
cases, i.e. are more _general_, and also, as being laws of nature, of
which the complex laws are but results, are more _certain_, i.e. more
_unconditional_ and more _universally true_. In the third process, laws
are resolved into others which are indeed more _general_, but not more
_certain_, since they are in fact the same laws, and therefore, subject
to the same exceptions.
Liebig's researches, e.g. into the Contagious Influence of Chemical
Action, and his Theory of Respiration, are among the finest examples,
since Newton's exposition of the law of gravitation, of the use of the
deductive method for _explanation_.[2] But the method is as available
for explaining mental as physical facts. It is destined to predominate
in philosophy. Before Bacon's time deductions were accepted as
sufficient, when neither had the premisses been established by proper
canons of experimental enquiry, nor the results tested by verification
by specific experience. He therefore changed the method of the sciences
from deductive to experimental. But, now that the principles of
deduction are better understood, it is rapidly reverting from
experimental to deductive. Only it must not be supposed that the
inductive part of the process is yet complete. Probably, few of the
great generalisations fitted to be the premisses for future deductions
will be found among truths now known. Some, doubtless, are yet unthought
of; others known only as laws of some limited class of facts, as
electricity once was. They will probably appear first in the shape of
hypotheses, needing to be tested by canons of legitimate induction.
FOOTNOTE:
[2] These, and other illustrations in chap. xiii., cannot be usefully
represented in an abridged form.
CHAPTER XIV.
THE LIMITS TO THE EXPLANATION OF LAWS OF NATURE. HYPOTHESES.