38 
TRANSACTIONS OF THE TEXAS ACADEMY OF SCIENCE. 
and space relations. It takes it as it finds it; it collates, measures, 
studies, and compares; it draws its conclusions, and lastly subjects them 
to trial and test. Those which stand the test are accepted provisionally, 
and those which fail are rejected, or are relegated back for further in¬ 
quiry and revision. Those which are accepted become, for the time be¬ 
ing, principles of science, and are used as the premises of further induc¬ 
tion. And yet all of them are held provisionally only, and subject to 
whatever changes or modifications the growth of induction may seem to 
demand. There is no higher validity for any of them than that of the 
proof on which they rest, and every step of that proof is open to criti¬ 
cism. In science it is always in order to challenge first principles. But 
the challenger must come armed with new proof as strong and trenchant 
as that which he proposes to attack, before his gage can be lifted or the 
lists thrown open to him. 
Modern civilization then is characterized by its rapid progressive im¬ 
provement in the condition of the nations or races in which it prevails. 
It is most conspicuous in its material aspects; but the progress has also 
been great, though less conspicuous, in respect to morals. This progress 
has resulted from the rapid increase of knowledge, which in turn is the 
result of the pursuit of knowledge by scientific methods. In brief, that 
which distinguishes the present civilization of western Europe and of the 
United States from that of antiquity and of Asia is modern science and 
the results which have emanated from it. This is a very sweeping and 
magnificent claim; but let us inquire into it a little more in detail. 
I have characterized science as the use of knowledge for increasing 
knowledge and for finding new uses of knowledge. Thus a double func¬ 
tion of science is suggested. As the progress of science and of its appli¬ 
cations becomes more rapid the distinction between these two functions 
becomes more and more marked. The first function, the finding of new 
knowledge, is most conspicuously inductive, though far from being ex¬ 
clusively so, and is frequently called “discovery.” The second func¬ 
tion, the finding of new uses for knowledge, is chiefly deductive, though 
often inductive, and is usually called “invention.” One of the most 
striking features of the more recent developments of science has been 
that discoveries are usually made by one set of men and inventions by 
another. A scientific discoverer is seldom a scientific inventor, and an 
inventor is still more seldom a discoverer. The two fields of mental 
activity have become almost separated. They require, respectively, dif¬ 
ferent casts of mind and different temperaments, and the mental qualifi¬ 
cations required in one field are apt to prove disqualifications in the 
other, though happily it is not alwaj^s so. The combination of qualities 
which makes a man at once a discoverer and an inventor is rare in the 
extreme; but it is sometimes found. Yet if the material progress of the 
