not alike mute with regard to all questions concerning cause and effect,
this sentence at least it will venture to pronounce, That a mental world,
or universe of ideas, requires a cause as much, as does a material world,
or universe of objects; and, if similar in its arrangement, must require
a similar cause. For what is there in this subject, which should occasion
a different conclusion or inference? In an abstract view, they are
entirely alike; and no difficulty attends the one supposition, which is
not common to both of them.

Again, when we will needs force Experience to pronounce some sentence,
even on these subjects which lie beyond her sphere, neither can she
perceive any material difference in this particular, between these two
kinds of worlds; but finds them to be governed by similar principles, and
to depend upon an equal variety of causes in their operations. We have
specimens in miniature of both of them. Our own mind resembles the one; a
vegetable or animal body the other. Let experience, therefore, judge from
these samples. Nothing seems more delicate, with regard to its causes,
than thought; and as these causes never operate in two persons after the
same manner, so we never find two persons who think exactly alike. Nor
indeed does the same person think exactly alike at any two different
periods of time. A difference of age, of the disposition of his body, of
weather, of food, of company, of books, of passions; any of these
particulars, or others more minute, are sufficient to alter the curious
machinery of thought, and communicate to it very different movements and
operations. As far as we can judge, vegetables and animal bodies are not
more delicate in their motions, nor depend upon a greater variety or more
curious adjustment of springs and principles.

How, therefore, shall we satisfy ourselves concerning the cause of that
Being whom you suppose the Author of Nature, or, according to your system