Is Certainty of God Credible?

Nov 21, 2022 | Blog Essays

Is Certainty of God Credible?

Is certainty of God credible? Many say that certainty is a fool’s game, that no one really knows if God is real or not. How could anything finite know the infinite? Surely there will always be doubt. Isn’t agnosticism the rational stance? And yet, millions do claim certainty about God, sometimes beyond all reasonable doubt, sometimes even absolute certainty. Are these people lacking critical judgement? Are they eccentric fanatics? Is there any reason to trust them?

In my youth, I puzzled over how God could make His presence known without doubt. I imagined Jesus appearing in holographic miniature, like Princess Leia in Star Wars. But how could a mere sensory image give certainty? Couldn’t that be faked? If God and the spiritual realm are real, perhaps there are demonic spirits too, with the power to deceive?

But couldn’t God deliver some experience to extinguish such doubt? If God is all-powerful, surely he could help us distinguish between true and false revelation of himself? Why should we limit his power to do so? The philosopher Robert Oakes discusses this possibility in his paper, Experience and Epistemological Miracles. Oakes argues that:

it is conceivable for there to occur self-authenticating experiences of God… [and that] there is no one who knows that self-authenticating experiences of God never in fact occur[i]

This point is key. Rather than: “no one really knows if God is real or not” the truth is really: no-one really knows that “self-authenticating experiences of God never in fact occur.” How could they know? How could anyone know that every single witness, ever, is a false witness?

This asymmetry of knowledge between the two possibilities, God-is and God-is-not, is vital to acknowledge. For the case God-is-not (a.k.a. atheism), we could mount a probabilistic argument for its truth; but even if God really does not exist, we could never be certain of that fact, for such negatives cannot be proven. God could always be hidden in this life. On the other hand, for the case God-is, there is always the possibility that God has revealed himself, or will reveal himself, in some self-authenticating experience.

An atheistic reality cannot seek-out and seduce its seeker; nor at opportune time reveal the splendour of its truth in intimate-knowing exchange of love. On the other hand, this is precisely what God does do according to the Christian mystics who claim experiential, certain knowledge of God. It is a courtship of love, they say, not simply a philosophical conundrum.

But can these mystics, these lovers of God, be trusted in their sackcloth, separated from the world, living in caves or monastic cells? I have in mind the likes of Saints Anthony the Great, Benedict of Nursia, Francis of Assisi, Bernard of Clairvaux, John of the Cross, Catherine of Siena, Teresa of Avila. Modern man, considering himself, or herself wise, and equipped with a smattering of neuroscience, does not think too highly of their truth claims. Scepticism is the wiser stance, they say.

Let us look briefly at the case for the credibility of certainty, then briefly the case against, before returning to the possibility of self-authenticating experience of God.


For Credible Certainty (in Brief)

Firstly, the Catholic Church is steadfast in her claim that God’s existence can be known with certainty. This is consistent over 2000 years, repeating what is proclaimed in the Gospels[ii]. This is shocking to some people. She also outlines how this certainty arises:

in order that the obedience of our faith might be in harmony with reason, God willed that, to the interior help of the Holy Spirit, there should be joined exterior proofs of His revelation…especially miracles and prophecies, which…. are most certain proofs of His Divine Revelation…[iii]

Thus, certainty is said to arise by the co-ordination “in harmony” of inner and outer, between “interior helps” of something supernatural (Holy Spirit) and exterior signs (prophecies and miracles) which are “many” and “divinely arranged” for “evident credibility”.

Further, the Church points to signs of her own credibility as witness to these things: her “marvellous propagation” in time and space, against all odds; her “exceptional holiness” in worship and lives of the Saints; her “fruitfulness in all good works” such as exceptional service to the poor; her “catholic unity” of specific creedal belief across diverse peoples; and her “invincible stability” existentially and intellectually despite persecution[iv].

Is there any other institution that can better these claims: 2000 years of continuous growth, holy saints, care of the poor, universality, unity, and stability? [iv]

So, despite the many faults and sins of her members, the Church proclaims that her official witness message, the Gospel of Christ, is to be trusted and given most careful consideration. This Gospel, or Good News, says that we can come to know God personally with certainty by following Jesus – not a feeling, not a hunch, but knowledge, with certainty.


Secondly, there is the continuous line of individual witnesses, many of whom proclaim an unshakeable certainty despite threat of torture and death. Such was the witness of St Cyprian (200-258 AD), a talented lawyer, who had a miraculous conversion, initiated by mystical light:

I myself was held in bonds by the innumerable errors of my previous life…But after that, by the help of the water of new birth, the stain of my former life was washed away, and a light from above, serene and pure, was infused into my reconciled heart… a second birth restored me to a new man. Then, in a wondrous manner every doubt began to fade…. I clearly understood that what had first lived within me, enslaved by the vices of the flesh, was earthly and that what, instead, the Holy Spirit had wrought within me was divine and heavenly.

It was the interior help of “a light from above” “infused” into his heart that led to “every doubt” fading away and a “divine and heavenly” vision. Cyprian then devoted himself to the Church, shared his wealth with the poor, and willingly accepted execution for proclaiming his faith. He was given the chance to save his skin, but replied,

A good will, which knows God, cannot be altered.

Such is the strength of Christian witness over 2000 years following a mysterious help “from above”. The Church would not exist without these witnesses. She is built upon their certainty-of-faith from Jesus and the Apostles onwards.

These witnesses are the very foundations and pillars of the Church. A close look at their lives, conversions, and transformations, is one long continuous witness to the same “interior help”, a light from above that becomes a light within. These men and women are not delusional oddballs incapable of reason. Many have outstanding intellectual and moral virtues, as is clear from the writings of the “Doctors of the Church” such as Augustine, Bonaventure, and Hildegard of Bingen. What is more, their fruits continue to flourish centuries after they died[v].

Lastly, the path through which these witnesses receive the gift of faith and sure knowledge of God, is the same each time. It is through Jesus Christ, His life, and His teachings, in particular through humble surrender and repentance, turning from love of self and world (darkness), to love of God (light). Jesus says that He and He alone is the gate and the gatekeeper (John 10:1-21). These witnesses confirm that Way and that Gate. This Way is further made believable by the sublimity and perfection of Jesus’ teaching on love which is, arguably, unsurpassed.

Thus, certainty is indeed credible, for the individual witnesses to certainty are credible. They are men and women, transformed by grace; and they have become the very foundations of an edifice of devotion, service, and charity without compare.[iv]

Against Credible Certainty (in Brief)

Not so! Cries the sceptic.

Richard Dawkins, who has no psychiatric or theological expertise, asserts that all conversions, such as St Cyprian’s or St Augustine’s, are akin to the delusions of those who “think they are Napoleon or Charlie Chaplin” living in asylums. “We humour them” he says, adding,

Religious experiences are different only in that the people who claim to have them are numerous.[vi]

Is that so? I would never confuse a Christian prayer group for a group suffering from psychosis. Nor I suspect, would Dawkins, though one cannot be sure.

We must admit, however, that the sceptic does have a case, even if the New Atheist rhetoric is exaggerated. People in other religions often profess certainty too, in their God and their way, often conflicting with Christ. They cannot all be right.

Further, zealous conviction is not infrequently associated with fanaticism, even violence. Not all martyrdom is good. There is also a murderous martyrdom, and it too has its unshakeable witnesses. So why should anyone trust a claim of certainty about God? Doesn’t it lack epistemic caution and humility?

Sceptics will draw upon the cognitive science of religion (CSR) showing that mystical experience can be produced artificially by stimulating the brain or taking psychedelic drugs[vii].

CSR also demonstrates that we are biased towards inferring agency, including supernatural agency, even when none exists, and that we are primed to use supernatural concepts, such as magic and mind-reading. Together with other cognitive biases, sceptics have no shortage of tools from which to construct a naturalised account of God-beliefs and entire religions. Having done so, they claim that nothing supernatural need be added.[viii]

Surely this naturalised religion better accounts for other features too, such as God’s hiddenness, or the presence of gratuitous suffering? If God exists and is all powerful and good, why does he hide from those who seek him, and why does he allow gratuitous suffering? We need only mention the Jewish Holocaust to see the power of this argument. Such things seem less puzzling, sceptics say, if God is only imaginary.

It is little surprise therefore that many sceptics think religion’s time is up, that all claims to certain knowledge of God are false. They will admit, however, that they cannot be sure, in line with the philosopher Oakes. Nevertheless, believing that God probably-doesn’t-exist, many feel justified in crusading against Christian belief, making special note of the Church’s failures, such as the sex abuse crisis. It all adds up, they say, to a false system, lacking in holiness and lacking God. Even on the slim chance that God does exist, they say, there are so many reasons to doubt our perceptions that no-one could ever have objective certainty. So, certainty is simply not credible. What could be more prudent than this?


Before returning to the “interior witness” “from above” that the Church proclaims, let me answer some of these objections, or at least point to possible answers.


Answers to Some Objections

The sceptical stance can appear very persuasive on the surface, but on looking deeper none of the objections really discredit the positive evidence. The claim that cognitive science of religion (CSR) has explained away religious experience and belief in natural terms is greatly exaggerated and sometimes commits the “genetic fallacy”[ix]. See the book length critiques by Van Eyghen and Jones[x]. Some brief points:

  • CSR often lacks details and data to back up its causal-explanatory claims
  • CSR is too limited in scope to explain the whole of religious experience and expression, e.g., the lives of the Saints who are so central to the building of the Church.
  • Finding neural correlates of religious experience does not falsify the truth content. Finding neural correlates of “being in love” does not negate the reality of “being in love”.
  • CSR has not shown that supernatural beliefs are generally unreliably formed.

As for the problems of evil and suffering, and God’s hiddenness, these may look puzzling from the standpoint of an atheist imagining how a good God ought to act according to their (atheist) ideas. However, from a truly Christian theological perspective of creation-fall-salvation, and the turning of the soul from darkness to light, these features make profound sense of our complex reality. It is difficult to accept that we are in spiritual darkness, thus spiritually blind, unless or until we turn fully to Christ, but that is precisely the experience at Christian spiritual conversion – an experience consistent for two thousand years. A greater light becomes known that casts the lesser, worldly light into shade. This occurs through willing co-operation with grace, in humility, not by the conclusion of an argument. What was previously not understood, becomes understood:

 And the light shineth in darkness: and the darkness did not comprehend it – John 1:5

Lastly, regarding other religions, the fanaticism of murderous “martyrdom” does nothing to discredit the convictions of true martyrdom (willing self-sacrifice for the good of others). Nor does authentic religious experience outside of Christianity discredit the unique claims of the Gospel. After all, according to the Gospel, Christ is the Divine Logos, through which all came to be. Even if one has never heard of Jesus, a good heart seeking God may still make authentic progress. Sudden, complete forgiveness of sins through mystical encounter, however, does seem to be uniquely associated with Jesus[xi].

Thus, these common objections to undermine belief in God, including the possibility of certainty, are not successful. The positive evidence still stands. So let us return to the mysterious “interior help” that the Church proclaims and re-consider the possibility of Divinely self-authenticating experience.


Jesus and the “Interior help”

Jesus’ promise to send an “interior help” to his disciples is emphatic and particular. It is not a peripheral teaching but is central to the whole Gospel message. If this “interior help” never materialised in the form promised, Christianity would be false. On the other hand, if it has materialised, then it points to Christianity’s truth and the credibility of certainty. To recall, it is by this interior help that certainty is said to arise.

Here are Jesus’ words:

I am sending upon you what my Father promised; so stay here in the city until you have been clothed with power from on high. (Luke 24:49) …you will be baptised with the Holy Spirit not many days from now…you will receive power when the Holy Spirit has come upon you; and you will be my witnesses…to the ends of the earth. (Acts 1:5, 8)

And I will ask the Father, and he will give you another Advocate, to be with you forever. This is the Spirit of truth, whom the world cannot receive, because it neither sees him nor knows him. You know him, because he abides with you, and he will be in you. (John 14:16-17)

When the Spirit of truth comes, he will guide you into all the truth (John 16:13),

This discourse is part of how Jesus conveys the manner in which he will “reveal [him]self to them” (John 14:21). So, not a holographic Princess Leia-type appearance, like the one I imagineed in my youth, but an interior “Spirit” who “abides with” and “in” those who receive it, who will “guide” them intentionally “into all the truth” so that they “know the truth” and are set “free” (John 8:32).


From Pentecost Onwards

I am squeezing into this last section what ought to take up a whole book. The question is whether anyone has received this “interior help” who abides within and guides to knowledge of the truth?

If we believe Luke-Acts, written by a physician who clearly respected historical detail, then the Holy Spirit descended upon Jesus’ disciples at Pentecost, just as Jesus had promised:

Divided tongues, as of fire, appeared among them, and a tongue rested on each of them. All of them were filled with the Holy Spirit …the Spirit gave them ability.” (Acts 2:1–4)

Holy Spirit

Pentecost, El Geco (Ca. 1600)

Perhaps we are sceptical of scripture? Then we have St Cyprian’s testimony from the 3rd century AD of “a light from above, serene and pure…infused into my reconciled heart” (discussed above), or St Augustine’s from the 4th, or St Hildegard’s from the 12th , or St Francis from the 13th. The point is that their accounts are all analogous, and there are many more. They have a common specific core, in keeping with Jesus’s promise and the description of descending light, like “tongues…of fire” resting upon each disciple, filling them.

Let me finish with the testimony of a young man, Francis, from the 13th century, whose life, by anyone’s standards has born great fruits. Thomas Celarno wrote this account of Francis’ conversion in 1228, just a few years after his death:

Day by day the blessed father Francis was being filled with the consolation and the grace of the Holy Spirit …. Certainty of the forgiveness of all his sins poured in, and the assurance of being revived in grace was given to him. Then he was caught up above himself and totally engulfed in light and, with his inmost soul opened wide, he clearly saw the future. As that sweetness and light withdrew, renewed in spirit, he now seemed to be changed into another man.

The future that the young Francis saw whilst “engulfed in light” was:

 a great multitude of people coming to us, wishing to live with us in the habit of a holy way of life and in the rule of blessed religion.

As with St Cyprian’s conversion and like at Pentecost, Francis’ conversion involved mystical light from above giving complete forgiveness of sins, certainty, and new ability. Today there are some 650,000 Franciscans in 110 countries and nearly 35,000 Franciscan friars of various kinds, so his prophetic vision of “a great multitude of people coming to us” has also come true.[xii]

Was Francis lying? Was his biographer lying? Was Luke the evangelist lying? And the Apostles too? How could such lies be perpetuated for 2000 years? And how would they give rise to such great legacies of self-sacrificing charity? On careful reflection of all the elements, neither lies, nor illusions explain this mystical light from above that reconciles hearts to God, turning them into disciples.

It is a story repeated over and over in the lives of the Saints who are the pillars of the Church. St Ignatius who founded the Society of Jesus, the “Jesuits”, is another example. As well as these well-known Saints who answered the discipleship call with utmost courage and self-giving, there are countless others who have received the Holy Spirit in the same manner:

  • mystical light from above
  • complete forgiveness of sins
  • new creation within – a “new heart”
  • new ability
  • indwelling presence
  • complete joy & sublime peace.

Much more could be said of this mystery, but this will have to wait for another blog. I have said enough to begin the case.


So, is certainty of God’s existence credible? I answer yes, and that this credibility can be seen even prior to conversion. There are so many outstanding witnesses of the promised “interior help”, and these men and women are the very heart of the Church. They have kept and renewed the Church, like a rock, against tides and troubles for 2000 years. The Church’s endurance, good works and stability are simply not well explained by the complex of lies and illusions that sceptics are forced to propose.

Much more needs to be said of this mysterious “interior witness”, who comes in the form of light, and leads disciples from subjective convictions to objective truth. I will examine this in a future blog on the evidential role of religious experience. I will also examine Old Testament prophecies that foretell this mystery, and argue why this “interior help” is indeed fulfilment of them.

A new heart I will give you, and a new spirit I will put within you; and I will remove from your body the heart of stone and give you a heart of flesh. I will put my spirit within you, and make you follow my statutes and be careful to observe my ordinances. (Ezekiel 36:26–27)

I have given you as a covenant to the people, a light to the nations, to open the eyes that are blind, to bring out…those who sit in darkness. (Isaiah 42:6–7)

From this harmony of reasons: 1) the prophetic promise of an “interior help”, 2) its fulfilment at Pentecost, 3) a stream of credible witnesses ever since, 4) many with exceptional lasting fruit, I argue, that certainty of God is very credible indeed, and that Divinely self-authenticating experience is a reality.


They who have my commandments and keep them are those who love me; and those who love me will be loved by my Father, and I will love them and reveal myself to them.

John 14:21


Notes & References:

[i] Oakes, R. (1981). Religious Experience and Epistemological Miracles: A Moderate Defense of Theistic Mysticism. International Journal for Philosophy of Religion, 12(2), 97–110.

[ii] Jesus says emphatically “and you will know the truth, and the truth will make you free.” (John 8:32). Jesus never says, “you will feel” or “you will sense” the truth, but “you will know”. It is knowledge that Jesus stresses.

[iii] First Vatican Council (1870) Dogmatic Constitution on the Catholic Faith – Dei Filius

[iv] For evidence of exceptional service to the poor, see:

Catholic Church: World’s biggest charitable organization, Dr. Jose Mario Bautista Maximiano (2018)

The world’s biggest charity, David Paton (2017)

[v] Doctors of the Catholic Church – Definition and Complete List, Dr. Marcellino D’Ambrosio (2022)

[vi] Dawkins, Richard (2006), The God Delusion

[vii] Yaden B. David & Newberg, Andrew (2022) The Varieties of Spiritual Experience 21st Century Research and Perspectives. Oxford University Press.

Letheby, Chris (2021) Philosophy of Psychedelics (International Perspectives in Philosophy and Psychiatry), Oxford University Press.

[viii] Boyer, Pascal (2001) Religion Explained. Basic Books.

Atran, S. (2002) In Gods We Trust. The Evolutionary Landscape of Religion. Oxford: Oxford University Press

Boyer, P. (2003) Religious Thought and Behavior as By-Products of Brain Function. Trends in Cognitive Science 7, no. 3: 119–124

Dennett, Daniel (2006) Breaking the Spell. Religion as a Natural Phenomenon. London: Penguin

[ix] Rezkalla, Paul (2015). Does Cognitive Science of Religion Undermine Religious Belief? Philosophy and Cosmology 14 (1):215-221

[x] Van Eyghen, H. (2020). Arguing From Cognitive Science of Religion. Is Religious Belief Debunked? Bloomsbury Academic.

Jones, James, W. (2016) Can Science Explain Religion? The Cognitive Science Debate. Oxford: Oxford University Press

[xi] This point is illustrated well in a PhD study of mystical conversion in India amongst Hindus, Sikhs, and Muslims: Joshua Iyadurai (2015) Transformative Religious Experience: A Phenomenological Understanding of Religious Conversion. Imprint: Pickwick Publications.


by Andrew JR Parker

Grateful to Christ. Proclaiming the Word of God.