Others distinguish between the _Speculative_ and the _Practical_ Reason; and hold that while the former cannot prove by an unexceptionable argument the existence of God, the latter affords a sufficient groundwork for religious belief and worship.

Others, again, speak not so much of reason or reasoning, as of _sentiment and instinct_, as the source of our religious beliefs; and instead of addressing arguments to the understanding, they would make their appeal to the feelings and affections of the heart.

There is still another class of writers who resolve all human knowledge, whether relating to things secular or spiritual, into what they call the principle of faith (_foi_), and to this class belong two distinct parties who are widely different from each other in almost everything else.

It is important, therefore, to mark the radical difference between their respective systems, since it is apt to be concealed or disguised by the ambiguous use of the same phraseology by both.

The one party may be described as the disciples of a _Faith-Philosophy of Reason_, the other of a _Faith-Philosophy of Revelation_: the former resolving all our knowledge into the intuitive perceptions or first principles of the human intellect, considered as a kind of divine and infallible, though natural inspiration; the latter contending that in regard at least to the knowledge of theological truth, human reason is utterly powerless, and can only arrive at certainty by faith in the divine testimony.