case in point, an opinion fraught with probability, _solid,
comparative, practical probability_. The doubt must not be mere
negative doubt, or ignorance that cannot tell why it doubts; not a
vague suspicion, or sentimental impression that defies all
intellectual analysis; not a mere subjective inability to make up
one's mind, but some counter-reason that admits of positive statement,
as we say, _in black and white_. It is true that many minds cannot
define their grounds of doubt, even when these are real. Such minds
are unfit to apply the doctrine of Probabilism to themselves, but must
seek its application from others. The opinion against the law, when
explicitly drawn out, must be found to possess a _solid_ probability.
It may be either an intrinsic argument from reason and the nature of
the case, or an extrinsic argument from the word of some authority:
but the reason or the authority must be grave. The opinion is thus
said to be _intrinsically_ or _extrinsically_ probable. The
probability must also be _comparative_. There is many an argument, in
itself a very good one, that perishes when we come to consider the
crushing weight of evidence on the other side. An opinion is
_comparatively_ probable, when after hearing all the reasons and all
the authorities on the other side, the said opinion still remains _not
unlikely_, which is all that we mean to say of an opinion here, when
we call it _probable_. In ordinary English, the word _probable_ means
_more likely than otherwise_, which is not the signification of the
Latin _opinio probabilis_. Lastly, the probability must be
_practical_: it must take account of all the circumstances of the
case. Practical probability is opposed to _speculative_, which leaves
out of count certain circumstances, which are pretty sure to be
present, and to make all the difference in the issue. Thus it is
speculatively probable that a Catholic might without sin remain years
without confession, never having any grievous sins to confess,