40 JOURNAL OF SCIENCE. 
That the earth was so fixed and steadfast, and that the sun, moon, 
and stars ran their daily course round it, were regarded as facts 
clearly established by the testimony of every man’s senses, and 
therefore beyond the possibility of doubt or cavil. At the present 
time, however, it is mere common-place to say that the alleged 
facts are not facts at all, that they never were facts attested by 
the senses, but false inferences hastily drawn from sense impres- 
sions in themselves perfectly trustworthy. This shows the great 
danger of taking appearances for facts, which is one of the com- 
monest vices of ordinary observation. 
« Let me now contrast with this the observation of the men of 
science. And first, the scientific observer has a definite object in 
view, and every observation he makes has some relation to the 
proposed end. In this way his facts are full of meaning, being 
seen in their relation to one another and to the whole system of 
which they form a part. They are no longer regarded as isolated 
and unconnected phenomena, but as being naturally related and 
forming necessary parts of one organic whole. ‘The observer is 
penetrated bya firm conviction of the supremacy of law and order, 
and every new fact is to him peculiarly significant, tending as it 
does to confirm his anticipation, or suggesting some necessary 
limitation or modification. He has tully grasped the important 
idea of variety in unity ; and this idea, ever present with him, 
gives a meaning and value to observed facts, of which the unscien- 
tific mind can form no adequate conception. 
“But again, the man of science is very careful as to what he 
admits as facts. He, therefore, submits apparent facts to the most 
rigorous scrutiny, and for this purpose employs aids and appli- 
ances, which the ordinary observer never dreams of. All complex 
facts must undergo caretul analysis in order to separate what is 
original and necessary from all that is adventitious and acquired 
Judgments regarding the eternal world and all the objects of sense 
are peculiarly liable to be of a mixed and complex character ; and 
it is an important function of analysis toseparate the pure, simple, 
sense impressions from the associations and inferences which 
gradually gather round them, and with which they are too apt to 
be confounded. ‘The ordinary man believes that he sees the sun 
moving round from east to west, that what he feels as heat is in 
the sun or the fire, that colour is in the flowers, and that the 
pleasant taste aud odour are undoubtedly in the apple. The man 
of science, on the other hand, submits the so-called facts to a 
rigorous examination; he analysis, discriminates, and distinguishes, 
and thus arrives at the conclusion that the popular belief is not 
in accordance with existing facts. 
‘JT. In the next place I would ask your attention to the dif- 
ference between ordinary and scientific knowledge in regard to the 
classification of objects. This process is original and fundamental, 
and is therefore common to all knowledge. Things in order.to be 
known at all must be distinguished from those that differ from 
them, and must be assimilated to those of a like kind. The ex- 
tent to which the grouping or classifying of objects and giving 
them proper names has been carried out in the ordinary knowledge 
of mankind is very striking. As evidence of this we have only to 
look at a few of the general or common names used in our every- 
day speech. Each of these names as you are aware is the distin- 
