229 
and showed how an eye acts just as an optical instrument in 
forming images of external objects on the retina. At this tho 
Irenians were taken aback. They had been used to regard the 
sense of sight as an immediate gift from the Creator, depending 
on no second causes, and now they saw part of their organs 
of vision acting like so much dead matter. They received 
a shock, at which some of them were staggered, and*[asked 
themselves the question, Is it possible that, after all, this 
beautiful scene around us, these trees and flowers and painted 
butterflies, are merely a casual result of the blind interaction 
of a few simple laws ? 
But when the expedition had sailed from their shores, and 
the Irenians were left to themselves, and the novelty of their 
new ideas had a little worn off, a more sober judgment was 
formed of what they had learned. It is true that human 
reason had broken in on what they had been in the habit of 
regarding as holy ground ; and they had learned that up to 
the formation of images on the retina the eye behaves like a 
mere optical instrument. But how came it to pass that ^its 
parts were so strangely well-adapted to fulfil this end ? he 
cornea smooth and transparent, and nearly spherical, yet 
somewhat prolate, which as we kno w would tend to destroy 
spherical aberration ; the crystalline lens shaped much like 
the lens of an optician, yet becoming gradually denser towards 
the centre, in a manner that the optician cannot imitate ; the 
iris regulating the quantity of light admitted just as the 
astronomer regulates the aperture of his telescope, but self- 
acting in a manner which the optician cannot imitate ? Re- 
flecting on these things they became overwhelmingly impressed 
with the evidence of design, and design must have had a 
designer. But they had learned to think of him differently 
in some respects from what they did before ; to regard it as 
no derogation of his character to suppose that he accomplishes 
his ends in conformity with, rather than in supersession of, 
such natural laws as they can themselves investigate, and 
doubtless of many others which are beyond their ken. 
Now the progress of science is continually placing us more 
or less in the condition of our imaginary islanders, by reducing 
to a result of the straightforward operation of natural laws 
processes, perhaps evidently beneficial in their effect, but which 
were at one time shrouded in myster3 T as to their nature. And 
it behoves us to keep our minds in a condition of sober im- 
partiality, neither on the one hand being so carried away by 
the achievements of science as to forget how much there is 
which science holds out no prospect of ever being able to 
explain, nor on the other refusing to admit conclusions fairly 
VOL. XIV. R 
