That he recognized that the test of the character of his inner experiences, for good or ill, was to be finally found in what they led him to, is shown by the following passage, already quoted, from the diary:  “What I do I must do, for it is not I that do it; it is the Spirit.  What that Spirit may be is a question I cannot answer.  What it leads me to do will be the only evidence of its character.  I feel as impersonal as a stranger to it.”

The aid which fidelity to the light of reason and the cherishing and obeying the inspirations of the Holy Spirit lends to the discovery of the fulness of truth is shown by the following extract from an article by Father Hecker in The Catholic World of October, 1887: 

“The man who establishes the historical identity of the Church of to-day with the Apostolic college says the doctrines now taught must be true; the man who perceives the identity of the Church’s doctrines with his own highest aspirations also proves them true.  The man who has become responsive to the primitive action of his reason says that the Church, which is its only authoritative exponent, must be a divinely appointed teacher.  The infallible authority of the Church in her past, present, and future teaching is established by the necessity of the truths which she teaches for the welfare of the human race, by thus completing the outlines of natural truth drawn by the divine hand in human consciousness.”

By this we see that, if the divine inner life had need of the divine outer life for its integrity, it is equally certain that in his case, and also in that of Dr. Brownson, the intimate action of God within was a pointer to the true Church of the Divine Word incarnate in the actual world of humanity:  for Dr. Brownson chiefly in the intellectual order, for Isaac Hecker in both the intellectual and mystical.  We have no fear of wearying the reader with the length of an extract of such value as the following: 

“The one who reaches Catholicity by the philosophical road, as Brownson did, by no means pretends that the problem of human destiny can be solved by mere force of reason:  Catholicity is not rationalism.  Nor does he pretend that the product of reason’s action, the knowledge of human immortality and liberty and of the being of God, place man apart from or above the universal action of God upon all souls by means of a visible society and external ordinances:  Catholicity is well named; it is universal.  But he knows that when a man is persuaded of a truth philosophically he is not called upon by his intelligence or his conscience to base it upon historical evidence; it is enough that he has one source of certitude in its favor.  It may be a truth first known by revelation, but if the human intelligence is capable of receiving it in revelation it must have some element of kinship to the truths of pure reason.  As in the order of nature men are like unto God, so is there a likeness between the truth of God naturally known and that known only by revelation.