Dear Professor James: A century has passed since you delivered the 20 Gifford Lectures on natural religion at Edinburgh, and published them as The Varieties of Religious Experience. We are celebrating this occasion, my students and I, and your friends around the world, as the 100th birthday of the greatest modern book on personal religion.

Why does the Varieties endure when other academic studies of religion become so quickly dated? You founded neither sect nor school; you left no retainers behind to reduce your insights to tiresome research protocols. Yet your personal bias is perfectly obvious. You love religion, but can’t commit yourself to its practice; you give every benefit of the doubt to personal experience, but you distrust the voice of tradition; you value spontaneity against experience “at second hand”; you appreciate mystical revelation when it’s idiosyncratic, but you’re uncomfortable when it comes in magisterial form.

Your piecemeal supernaturalism is an improvement on the tepid antisupernaturalism of much religious liberalism, but it’s no match for fully realized expressions of faith. Your famous powers of empathy fail you when it comes to ecclesial forms of Christianity. Nonetheless, your work endures while others lose currency as soon as they wear thin enough to reveal their ideological slant.

You remain the unsurpassed defender of religious experience against theories that reduce it to the product of this or that implacable force. In your first Gifford lecture you argued that the meaning of a religious experience should be sought in its “fruits for life” rather than in the peculiar circumstances (a mind-bending drug, a brush with death) that may have triggered it. “Immediate luminousness, philosophical reasonableness, moral helpfulness”—these were the criteria you proposed for testing the staying power and validity of a religious experience.

You knew all too well what it was like to seek refuge in a higher power when crushed by depression and “panic fear,” but you also realized that such experience was not enough to create a lasting faith. The traditional route to saving truth was blocked for you, so in its place you put pragmatism: judge all beliefs by their consequences, test all experiences by the degree to which they make one fit for life.

Composing your Gifford Lectures in the sickbed where you tried to rally your ailing heart and fragile nerves, you naturally tended to equate religious experience with healing and recovery. This was its “cash value.” Yet your pragmatism was not a new form of skepticism but an old form of practical wisdom—the wisdom practiced by masters of spiritual discernment from Cassian to Teresa of Ávila to Jonathan Edwards, who understand that one must test everything and hold fast to what is good.

Varieties should have been the death knell of reductionism for all time. You demonstrated beyond reasonable doubt that there is “a wider self through which saving experiences come” and that “where God is, tragedy is only provisional and partial, and shipwreck and dissolution are not the absolutely final things.” Yet in every generation the battle must be fought anew, for the spirit of reductionism is always with us, altering its face only enough to fool the unaware. No longer does one hear faith reduced to disorders of the liver or spleen: the new reductionism claims that we can explain all of our spiritual longings, our idols and fears, our sexual identity, our image of God, as cultural constructions. You are still needed to knock over needless obstacles and clear the path to faith, a path you discerned even when you could not follow it.

In June 1901, when you were close to finishing the first course of lectures, you wrote to a Christian friend:

I believe myself to be (probably) permanently incapable of believing the Christian scheme of vicarious salvation. . . . the ground I am taking is this: The mother-sea and fountain-head of all religions lies in the mystical experiences of the individual, taking the word mystical in a very wide sense. All theologies and all ecclesiasticisms are secondary growths superimposed.

You composed your Gifford Lectures as an act of homage to the mystical piety of your maverick Swedenborgian father, who did everything he could to instill in his children a lifelong allergy to institutional religion. How sad that this allergy kept you from grasping the supernatural reality of the church as the fellowship of saints to which by grace you belong. Had you entered the church while still living, you might have been spared the burden of longing for religious experience. To live at second hand from the fountain of eternal life is, after all, not such a bad thing.

I take the liberty of saying this because you were always a friend to eccentrics: the ponderous autodidact Benjamin Paul Blood with his nitrous oxide revelations, the brilliant misfit Charles Sanders Peirce, the psychical researchers you took seriously if only because, like pragmatism, they “unstiffened” our thought. Recall Josiah Royce’s tribute: “[Some critical people say] that James has always been too fond of cranks, and that the cranks have loved him. Well, I am one of James’s cranks. He was good to me, and I love him.”

Believe me, with affectionate regard,

Another one of your cranks.