herwise,' continued Jefferson; 'and events have proved their
lamentable error; for after thirty years of war, foreign and domestic,
the loss of millions of lives, the prostration of private happiness,
and the foreign subjugation of their own country for a time, they have
obtained no more, nor even that securely.'[2]

Let me, in concluding these observations, sum up in a few words some
other advantages which you may derive from history. It is, I think,
one of the best schools for that kind of reasoning which is most
useful in practical life. It teaches men to weigh conflicting
probabilities, to estimate degrees of evidence, to form a sound
judgment of the value of authorities. Reasoning is taught by actual
practice much more than by any _a priori_ methods. Many good
judges--and I own I am inclined to agree with them--doubt much whether
a study of formal logic ever yet made a good reasoner. Mathematics are
no doubt invaluable in this respect, but they only deal with
demonstrations; and it has often been observed how many excellent
mathematicians are somewhat peculiarly destitute of the power of
measuring degrees of probability. But history is largely concerned
with the kind of probabilities on which the conduct of life mainly
depends. There is one hint about historical reasoning which I think
may not be unworthy of your notice. When studying some great
historical controversy, place yourselves by an effort of the
imagination alternately on each side of the battle; try to realise as
fully as you can the point of view of the best men on either side, and
then draw up upon paper the arguments of each in the strongest form
you can give them. You will find that few practices do more to
elucidate the past, or form a better mental discipline.

History, again, greatly expands our horizon and enlarges our
experience by bringing us in direct contact with men of many times and
countries. It gives young men something of the experience of old men,
and untravelled men something of the experience of travelled ones. A
great source of error in our judgment of men is that we do not make
sufficient allowance for the difference of types. The essentials of
right and wrong no doubt continue the same, but if you look carefully
into history you will find that the special stress which is attached
to particular virtues is constantly changing. Sometimes it is the
civic virtues, sometimes the religious virtues, sometimes the
industrial virtues, some