Chapter VI

2. For the use of those not acquainted with the common notation
employed in this subject, it may be remarked that HH is simply an
abbreviated way of saying that the two successive throws of the
penny give head; HT that the first of them gives head, and the
second tail; and so on with the remaining symbols.

3. I am endeavouring to treat this rule of Sufficient Reason in a way
that shall be legitimate in the opinion of those who accept it, but
there seem very great doubts whether a contradiction is not involved
when we attempt to extract results from it. If the sides are
absolutely alike, how can there he any difference between the terms
of the series? The succession seems then reduced to a dull
uniformity, a mere iteration of the same thing many times; the
series we contemplated has disappeared. If the sides are not
absolutely alike, what becomes of the applicability of the rule?

4. _Formal Logic_, p. 185. _Principles of Science_, p. 208.

5. The close connection between these subjects is well indicated in
the title of Mr Whitworth's treatise, _Choice and Chance_.

6. _Essai Philosophique_. Ed. 1825, p. 74.

7. An opinion prevailed rather at one time (quoted and supported by
Quetelet amongst others) that the relative ages of the parents had
something to do with the sex of the offspring. If this were so, it
would quite bear out the above remarks. As a matter of fact, it
should be observed, that the proportion of 106 to 100 does not seem
by any means universal in all countries or at all times. For various
statistical tables on the subject see Quetelet, _Physique Sociale_,
Vol. I. 166, 173, 238.