488 
by the light of reason, we can only direct our steps by the 
darkness of prejudice. 
But we must go a step further. I agree with Bishop Butler 
that the only faculty which man has by which he can investi- 
tigate the contents of revelation itself, or its nature and 
tendencies, is that of reason ; and that it is the duty of reason 
to apply this test to anything which claims to have the cha- 
racter of a divine revelation. The whole process by which 
those who declaim most against the use of reason in the study 
of revelation is a rational one, only differing from others of the 
same kind by the assumption of premises of which no evidence 
exists. We can only persuade ourselves that we can quench 
the light of reason by invoking its aid in doing so. If in our 
despair of truth, we take refuge in the assumption of the 
existence of an infallible authority, the very constitution of 
our nature compels us to invoke the aid of our rational powers 
in this act of intellectual suicide. 
When, therefore, the friends of revelation denounce the 
use of reason, and speak of its profane efforts to pry into 
matters of revealed truth, they do infinite mischief to their 
cause. Many theological writers, who should have known 
better, have given countenance to this delusion. From them 
men of science have got hold of the false impression that 
theology does not rest on a rational basis. They forget that the 
only processes by which they have attained to their own beliefs 
are rational ones ; and that that which they denounce, as far 
as it is untrue, does not rest on a rational, but an irrational 
foundation. This state of mind is closely connected with that 
which leads to the convenient assumption that all orthodoxy 
is my doxy, and that all heterodoxy is every person else^s 
doxy. Every one who thinks at all must apply his reason, 
not only in yielding assent to any particular system of theo- 
logy, but in his study of revelation itself. The question 
is, not about the instrument which we must use, but its 
character, and the method of using it. On investigation it 
will be found, that the limits of our rational thought are those 
of our religious thought, and that the limits of religious 
thought are the limits of rational thought ; and that the 
ground of the supposed opposition between reason and reve- 
lation is the attempt to push our inquiries beyond the 
boundaries of rational thought. 
As a large portion of the sciences, and many of the deduc- 
tions of philosophy, rest on a basis which is short of actual 
demonstration, so a large portion of theology occupies a similar 
position. Perhaps it will be impossible ever to give to any 
portion of theology the precision which belongs to the pure 
