iS79-] 
The Course of Nature. 
85 
have described it, be considered as a product of modern 
investigation simply, or as belonging especially to the present 
age. It is a theory which has been, in a limited sphere, 
recognised by all men at all times. The reason why modern 
science has so greatly extended its scope is that modern 
science has acquired a vastly more extended view of nature 
than has before been obtained. One of the most curious 
and suggestive features of the teleological theory has been 
that the adtion of teleological causes has always been 
ascribed to operations into which human investigation 
could not penetrate, although their ultimate effedts might 
be plainly seen. Whenever the subjedt becomes so well 
understood that the chain of natural causes can be clearly 
followed, miracles and final causes cease, so far as the 
scientific explanation of things is concerned. That a ball 
or spear thrown in one diredtion would bend its course into 
an entirely different diredtion no one ever supposed. Homer 
never imagined Pallas as changing the course of the javelin 
after it had left the hand of Diomed. But those states of 
the nervous system which result in a certain and accurate aim 
or in a tremulous or uncontrolled arm, lay beyond the pale 
of physiological knowledge in the time of Homer; so here it 
was that the goddess intervened. When nervous adtion 
became fully understood, the final cause receded, and took 
refuge in some deeper arcanum of our ignorance. Jove was 
never expedted to make thunder and rain without clouds, 
nor was the falling of the rain ever ascribed to his inter- 
ference, because every one believed that if the drops were 
once formed they would fall at once to the ground, without 
any adtion on his part. But the mixing currents of moist 
and cool air, and the processes of condensation which lead 
to the formation of rain and eledtricity, were not understood, 
so here Jupiter had a chance to work unseen by man. 
When the mode t in which clouds were ‘formed was once 
understood, the god of thunder left his seat upon Mount 
Olympus for a more distant abode. From the earliest 
historic times, the man who took a large dose of poison has 
died, as a matter of course ; neither good nor evil spirit had 
anything to do with it; but if brain disease bereft him of 
reason, the malevolence of an evil spirit was called in to 
account for the result. 
Now, I beg you to notice that in all these cases, the only 
distinction we can make between those effedts which were 
supposed to be produced by natural causes and those which 
were produced by the will of some higher power, adting 
with a scrutable end in view, is this : in the first class 
