ement to the audience is especially helpful when the
speaker is dealing with technical subjects, or material with which
most people are not usually and widely conversant. Scientific
considerations always become clearer when such plans are simply
constructed, clearly announced, and plainly followed.

So far as I know, there are only three hypotheses which ever
have been entertained, or which well can be entertained,
respecting the past history of Nature. I will, in the first
place, state the hypotheses, and then I will consider what
evidence bearing upon them is in our possession, and by what
light of criticism that evidence is to be interpreted. Upon
the first hypothesis, the assumption is, that phenomena of
Nature similar to those exhibited by the present world have
always existed; in other words, that the universe has existed
from all eternity in what may be broadly termed its present
condition.

The second hypothesis is, that the present state of things
has had only a limited duration; and that, at some period in
the past, a condition of the world, essentially similar to
that which we now know, came into existence, without any
precedent condition from which it could have naturally
proceeded. The assumption that successive states of Nature
have arisen, each without any relation of natural causation
to an antecedent state, is a mere modification of this second
hypothesis.

The third hypothesis also assumes that the present state of
things has had but a limited duration; but it supposes that
this state has been evolved by a natural process from an
antecedent state, and that from another, and so on; and, on
this hypothesis, the attempt to assign any limit to the
series of past changes is, usually, given up.

THOMAS H. HUXLEY: _Lectures on Evolution_, 1876

EXERCISES

1. According to what methods are the foregoing plans arranged? Which
division in Sumner's speech was the most important? Was he trying to
get his listeners to do anything? What do you think that object was?

2. In Lincoln's speech do you think he planned the material
chronologically? Historically? What reasons have you for your answer?

3. Which of Webster's four parts is the most important? Give reasons
for your answer.

4. Which hypothesis (what does the word mean?) did Huxley himself
support? What induces you to think thus? Is this pl