such as make discoveries concerning the weakness and narrow limits of
human reason and capacity.

60. And what stronger instance can be produced of the surprising
ignorance and weakness of the understanding than the present? For
surely, if there be any relation among objects which it imports to us to
know perfectly, it is that of cause and effect. On this are founded all
our reasonings concerning matter of fact or existence. By means of it
alone we attain any assurance concerning objects which are removed from
the present testimony of our memory and senses. The only immediate
utility of all sciences, is to teach us, how to control and regulate
future events by their causes. Our thoughts and enquiries are,
therefore, every moment, employed about this relation: Yet so imperfect
are the ideas which we form concerning it, that it is impossible to give
any just definition of cause, except what is drawn from something
extraneous and foreign to it. Similar objects are always conjoined with
similar. Of this we have experience. Suitably to this experience,
therefore, we may define a cause to be _an object, followed by another,
and where all the objects similar to the first are followed by objects
similar to the second_. Or in other words _where, if the first object
had not been, the second never had existed_. The appearance of a cause
always conveys the mind, by a customary transition, to the idea of the
effect. Of this also we have experience. We may, therefore, suitably to
this experience, form another definition of cause, and call it, _an
object followed by another, and whose appearance always conveys the
thought to that other._ But though both these definitions be drawn from
circumstances foreign to the cause, we cannot remedy this inconvenience,
or attain any more perfect definition, which may point out that
circumstance in the cause, which gives it a connexion with its effect.
We have no idea of this connexion, nor even any distinct notion what it