nly able to indicate it by
a few touches; by an etching, not a photograph.

We have now added to the explanation before given of the province of our
inquiry, and of the law of the action of free thought on religion, an
account of the moral and intellectual causes which operate in the history
of unbelief, and have sufficiently explained the mode in which the subject
will be treated.

The use of the inquiry will, it is hoped, be apparent both in its
theoretical and practical relations. It is designed to have an
intellectual value not only as instruction but as argument. The tendency
of it will be in some degree polemical as well as didactic, refuting error
by analysing it into its causes, repelling present attacks by studying the
history of former ones.

It is one peculiar advantage belonging to the philosophical investigation
of the history of thought, that even the odious becomes valuable as an
object of study, the pathology of the soul as well as its normal action.
Philosophy takes cognisance of error as well as of truth, inasmuch as it
derives materials from both for discovering a theory of the grounds of
belief and disbelief. Hence it follows that the study of the natural
history of doubt combined with the literary, if it be the means of
affording an explanation of a large class of facts relating to the
religious history of man and the sphere of the remedial operations of
Christ's church, will have a practical value as well as speculative.

Such an inquiry, if it be directed, as in the present lectures, to the
analysis of the intellectual rather than the emotional element of
unbelief, as being that which has been less generally and less fully
explored, will require to be supplemented by a constant reference to the
intermixture of the other element, and the consequent necessity of taking
account of the latter in estimating the whole phenomenon of doubt. But
within its own sphere it will have a practical and polemical value, if the
course of the investigation shall show that the various forms of unbelief,
when studied from the intellectual side, are corollaries from certain
metaphysical or critical systems. The analysis itself will have indirectly
the force of an argument. The discovery of the causes of a disease
contains the germ of the cure. Error is refuted when it is referred to the
causes which produce it.

Nor will the practical value of the inquiry be restricted to its use as a
page in the spiritual history