16 THE DOCTRINE OF DESCENT, 
composed—possessed, moreover, of powers of compre- 
hension sufficient to submit all these facts to analysis, 
would be able to reduce to a single formula the motions 
of the largest heavenly body and of the lightest atom. 
To such a mind nothing would be uncertain, and the 
future, like the past, would lie open before it. The 
human mind in all the perfection which it has been able 
to give to astronomy, offers but a faint image of such 
a mind as this.” “All efforts of the human intellect in 
the search for truth tend to approach the mind above 
portrayed, but will always remain infinitely removed 
from it.” 
The Prussian physiologist then quotes the “ Thou 
art like the Spirit whom thou comprehendest” of Faust ;* 
and is of opinion that, in the abstract, the formula of 
the universe is therefore not impenetrable to the human 
intellect. But we own we are cordially indifferent to an 
abstract perfection which never comes to light, and 
regard the unattainableness of this vague formula of 
the universe as a very endurable limit to human inquiry. 
But independently of the dubious consolation of the 
formula of the universe, we must agree with Dubois- 
Reymond, when he considers that the limits, before 
which the highest conceivable intelligence must pause, 
are also insurmountable to man, 
In accordance with the views now prevailing among 
physicists and biologists, Dubois-Reymond has thus 
specified the only limit given to the investigation of 
nature®: “The knowledge of natural science, more closely 
defined above, is no real knowledge. In the attempt to 
comprehend the constant, to which the mutations in 
* Du gleichst dem Geist, den du begreifst, 
