Do any Christians purport to make testable predictions that any unbeliever can verify in their lifetime?

The short answer is, “No.”, (and I think the long answer would be pretty much the same).  (As below… if there are any denominations or other subgroups that do as described, they are misguided.  (See also 2 Thess 2: 9-10, Matt 24: 24.))

It might be deemed off-topic technically, but here is an explanation of why.

The short version of this is the following verse (Luke 16:31 — ESV from BibleGateway) (plus context).
He said to him, ‘If they do not hear Moses and the Prophets, neither will they be convinced if someone should rise from the dead.’”

Parenthetically…
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The core tenet of Christianity, relevantly, is that human beings are “fallen” (noting that the following principle applies to any kind of being that is a (moral) person).  This means that an initial choice to do evil (any evil at all), on the part of a hitherto sinless person, requires/results in (that is, involves) a change in their nature.  The idea is that such a choice was made at the beginning of human history by Adam and Eve, and that their offspring are born fallen.

I have an account of what this means in more detail, but that is not Biblical truth, and is probably distracting here.  The best account of it is, broadly, the Old Testament, and, more immediately, the behaviour that evinces it [fallenness], which is that the subject would rather be killed than repent — coarsely speaking.  …Also that human beings have a ludicrously strong tendency to worship anything other than the real God [search “idolatry”].

As for the behaviour that results from being fallen… the core idea is that fallen persons prefer evil, ceteris paribus, and that, “every intention of the thoughts of /their hearts/ /is/ only evil continually.” (from Gen 6: 5).  One does not tend to see this in oneself, but it is fairly obvious in other people.  (My current view is that this effect is actually amplified by political power [“Power corrupts.”], and that this can be seen in various political leaders present and past, with the leader of Belarus, and the military coup in Myanmar, as examples offhand.)

See for example Deut 28:1 - 29: 1, and Deut 31: 16-18.

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The idea there [returning to the above verse] is that an inescapably convincing, in-your-face miracle, such as unarguably raising someone from the dead, is not adequate to save a Fallen person… because the problem is not intellectual.

There is an example of this in {the rising from the dead} of the speaker of the above quote, and the effect that this had on his opponents.  (Actually, the Bible does not really bother treating this point; arguably, if they were happy to do away with Jesus particularly because he was sinless (John 10: 31-33, John 8: 46) and had miraculous power, then the point is well and truly made already.)  (See also Matt 16: 1-4, Mark 8: 11-13.)

There is also an account (perhaps amusing) of this phenomenon in play, in John 9: 1-34.

(One might also trawl through the gospels (Matthew, Mark, Luke and John), and read the full stories around various miracles, looking for relevant information.  Notably, Jesus often told the subjects to not tell others.  This is because of the other aspect of this picture, which is that people are happy to follow a doer of miracles — read “Jesus” — just for the miracles, without actually doing what he says and repenting. [I think there is a verse for that, but I can not think of it if there is.  Perhaps John 6: 66 and the story leading up to this.])

The Christian view is that the historical evidence about Jesus the Christ is fantastically strong (ask the local pastor/minister)… and that this includes numerous miracles.  The Christian view is also that this is radically inadequate to convert anyone… such that performing (for instance) a {raising from the dead} miracle, here and now, is relevantly quite futile.

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If one is willing to repent, no signs are needed… and if one is not willing to repent, signs will not change this.

None of these five are that rigorous, and they go in decreasing order of falsifiability, so the first is my best response. However, some may appeal to certain people differently, and they each have their own logic to them.

It also may depend on how closely they are working with someone. If I was proposing it to another rather than alone and doing a test, I might jump to number 4, “the 30-day prayer experiment”. It also provides better evidence for someone outside the experimenter. If alone, it would be low on the list.

They all have something or other to say about the question. They obviously wouldn’t mix.

1. God’s Medicine Bottle

Here is some information about Derek Prince’s test that he did in North Africa when he was sick. He talks about his experience and giving the test for others. The person has to have some ailment though; a minor one is sufficient.

He wrote a small book called God’s Medicine Bottle based on Proverbs 4 which is available by pdf; it says 65 pages but the pages are tiny and the words huge, probably 5-10 pages double spaced.

Proverbs 4:20-22 KJV emphasizes four steps as shown:

20 My son, attend to my words;

incline thine ear unto my sayings.

21 Let them not depart from thine eyes;

keep them in the midst of thine heart.

22 For they are life unto those that find them, and health to all their flesh.

Contents:

1. Take as Directed

2. Pay Close Attention

3. Bend Your Ear

4. Don't Let Them Out of Your Sight

5. Keep Them in Your Heart

2. Be Still until you Know

Joseph Benner offered the world two experiments. Both were based on the idea that if one can know the truth, then his mind will be in smooth coherence with reality. By the Pragmatic Theory of Truth, championed by William James; if his beliefs are true, he will have optimal functioning.

In his book, The Impersonal Life, Benner said that God only gave us one meditation and if we would just do it truth would come to us.

“Be still - and KNOW - I AM - God.” Based on

• Psalm 46:10 He says, "Be still, and know that I am God; I will be exalted among the nations, I will be exalted in the earth."

• Exodus 14:14 The LORD will fight for you; you need only to be still.

• Psalm 37:7 Be still before the Lord and wait patiently for him; fret not yourself over the one who prospers in his way, over the man who carries out evil devices!

• Psalm 62:5 For God alone, O my soul, wait in silence, for my hope is from him.

• Job 6:24 Teach me, and I will be silent; make me understand how I have gone astray

He claimed no one could spend much time doing this without contacting God. What counts as “much time” is open for debate.

He writes that God commands you: “Speak them just as they are herein written, trying to realize that the God of you commands and demands of your moral self implicit obedience. Study them, search out their hidden potency. Brood over them, carry them with you in your work, whatever it be. Make them the vital, dominating factor in your work, and all your creative thoughts. Save them 1000 times a day, until you have discovered all My innermost meaning. Until every cell of your body thrills in joyful response to the command to be still and instantly obeys.”

3. Repeat Basic Truth until you Know

Though the first sounded especially Biblical, and neither is that cut and dry, the second one actually seems bit more experimental and logical. Benner wrote in his book The Way Out that if something is intrinsic and true, then anyone who believes it will find his experience of reality going smoothly. Believing the truth reconciles the mind with the world. This is the best measure of whether beliefs are true. (This logic is similar to the above). In light of that: the most disbelieved yet true and important aspects of man and the true God can be summarized from the Bible in this phrase, as he writes:

“GOD LOVES AND CARES FOR ME AND IS GIVING ME ALL GOOD THINGS.

I LOVE HIM AND THINK HIS THOUGHTS AND DO ONLY THE THINGS HE WANTS ME TO DO.”

This represents the only reality if there is correct relation between God and man. Therefore if any intellect were to believe it, that mind and reality itself would be in correspondence .

Any system accurately representing reality in correspondence is not confused. This is one common definition of truth in philosophy as per the link. So the prediction is profound lack of confusion.

Philippians 4:8 ESV

Finally, brothers, whatever is true, whatever is honorable, whatever is just, whatever is pure, whatever is lovely, whatever is commendable, if there is any excellence, if there is anything worthy of praise, think about these things.

John 8:32 King James Version

32 And ye shall know the truth, and the truth shall make you free.

“All that is needed is to say this over and over again to yourself until you believe it absolutely, letting not a single doubt of it’s truth ever enter your mind… Try to realize the full truth of these words to feel it, to see yourself actually living in the consciousness of it… Whether you know it or not yet everything that is come into your life has been good for you, for through these things He has brought you to a place where you should be willing to look to and trust Him only, for all the good things He has had for you from the beginning. And it should be easy to love Him. And through consciously loving and trying to think His thoughts you can see that it opens your mind so that His thoughts come in… So do not pass [these words] by because they seem so simple and common place. Stay with them until all their glorious import dawns upon you and you feel the change that they will surely and quickly bring into your consciousness and therefore into your life and all your affairs.”

He also adds that all one needs is some way to keep it up. (He doesn’t give a time frame but I imagine it’d be quick if it really is true, maybe a dozen days straight?). This may require timers or other people or documentation or something. He goes on to say that this may smack of sort of a power of positive thinking/just believe/affirmation-ish/bunch of BS.

The reason it is different is because it is true. Affirmations fail because they are usually not expressions of what’s true, but rather expressions of what we want to be true. No one but a saint would pick that as what they most want, for it is true relation with the true God.

Psalm 139:17

How precious also are Your thoughts to me, O God! How vast is the sum of them!

Romans 12:2 ESV

Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect.

Philippians 2:5 ESV / 208 helpful votes

Have this mind among yourselves, which is yours in Christ Jesus,

1 Corinthians 2:14-16 ESV

The natural person does not accept the things of the Spirit of God, for they are folly to him, and he is not able to understand them because they are spiritually discerned. The spiritual person judges all things, but is himself to be judged by no one.

1 Peter 1:13 ESV

Therefore, preparing your minds for action, and being sober-minded, set your hope fully on the grace that will be brought to you at the revelation of Jesus Christ.

Psalm 144:3

O Lord, what is man, that You take knowledge of him? Or the son of man, that You think of him?

Amos 4:13

For behold, He who forms mountains and creates the wind And declares to man what are His thoughts,

1 Corinthians 2:16 kjv

For who has known the mind of the Lord, that he will instruct Him? But we have the mind of Christ.

4. The 30-day Prayer Experiment

There was an actual “30-day prayer experiment.” run for a decade or two by The Pittsburgh Experiment, a market-place ministry founded in 1955 by Rev. Sam Shoemaker, Rector of Calvary Episcopal Church. It survived long after.

“[The way] Sam impacted the lives of business leaders was a very simple tactic which he called the 30-day Prayer Experiment. To someone who was searching spiritually, Sam would offer to join with them for 30 days of prayer about a specific need. He challenged them to trust God to answer within that time frame. Amazingly, He almost always did!”

I like the “specific need” aspect is good because it makes measuring results much easier.

In 2015 The Pittsburgh Post Gazette summarized the process and reported it is still going 60 years later.

Another source said:

“Sam Shoemaker used to say that in the course of the “30-day prayer experiment,” one of two changes would take place. Either God would specifically answer the request in an unmistakable way, or he would dramatically change the heart of the person praying.

Both results are wonderful and remarkable—and they go hand in hand as living proof that the Lord’s care is directed toward us. Why? Because He truly is the One Who answers.”

5. Act as if / Do and know

“Dr. Bob” Smith, a cofounder of Alcoholics Anonymous offered a somewhat less rigorous challenge one might call an experiment. “Act as if” and know and see, or “Do and know.”

Based on this verse spoken by Christ, John 7:17 (KJV):

If any man will do his will, he shall know of the doctrine whether it be of God, or whether I speak of myself.

This particular experiment aside, that is one of the more powerful verses for claiming it can be tested!

One was supposed to try it for ten days and meet with a spiritual adviser, four times for a forty day experiment.

Pew Research indicates that around 41% of American Christians believe Jesus will return to Earthy by 2050

https://www.pewresearch.org/fact-tank/2010/07/14/jesus-christs-return-to-earth/

This is of course testable.

However, it should be noted that Christians have thought the end of times were imminent for as long as there have been Christians. There's scriptural support for the belief that the end of times should have happened actually relatively soon after Jesus death. You won't find any time in history where Christians WEREN'T saying that the end is near.

History also tells us that the groups who are making these types of prophecies don't tend to change their beliefs when the prophecies don't come to pass, so... there's that.

Edit: this link is notable in regards to what happens to a group after a failed prophecy: https://slate.com/technology/2011/05/apocalypse-2011-what-happens-to-a-doomsday-cult-when-the-world-doesn-t-end.html

Yes, "Prayer works". However it is really difficult to effectively perform a study on the phenomona and no one has managed yet.

Many people, including many Christians as well as those of many other faiths, believe that prayer can have an objective effect on the world. In particular they hold that one can improve a sick individuals chance of recovery by praying for them, requesting Gods intervention in the progress of the disease. If this is true, it should be measurable.

This has been tried a number of times. There is a peer reviewed summary of these efforts here, and their summary is:

Prayer has been reported to improve outcomes in human as well as nonhuman species, to have no effect on outcomes, to worsen outcomes and to have retrospective healing effects. For a multitude of reasons, research on the healing effects of prayer is riddled with assumptions, challenges and contradictions that make the subject a scientific and religious minefield. We believe that the research has led nowhere, and that future research, if any, will forever be constrained by the scientific limitations that we outline.

They go on to list multiple issues that need to be addressed to effectively answer this question, as well as theosophical issues raised by the research. I suggest you read the source material for more details, as I am not really qualified to summarise them further and it is quite accessible to a non-scientific audience.

My personal opinion is that these challenges are far from insurmountable, compared to the really difficult challenges that the scientific community has overcome. I also do not accept their statements about the nature of God. The covid pandemic should have been the perfect opportunity to implement such a study, and it is a question why the funding for such a study is not available in the presence of multiple well funded institutions who would benefit from a positive result from such a study.

Yes, many times - and it's not worked out well for them

Any claim or prediction which could be proved true can equally well be proved false if it does not match the real world.

Over time, many Christian sects or Christian thinkers have used the Bible to make claims/predictions which have been disproved. Some examples are:-

The geocentric astronomical model

Based on the texts of Genesis, the Catholic Church's doctrine was that the Sun must orbit the Earth. Copernicus was the first to dispute this, but died before the Catholic Church could take decisive action against him. Opposition grew over the next century or so, until astronomical observations and Newton's laws of gravity and motion decisively proved the Church to be wrong. The Catholic Church quietly reversed its position over the 18th and 19th centuries.

Young Earth creationism

Many different religions, or leading members of religions, have used their respective holy texts to attempt to establish an exact date at which the world was created. In Christianity the most famous example is probably Bishop Ussher, but his was merely the most recent attempt. No religion gets close to the actual time required for accretion discs to form around stars and the rest of the timescale for planetary formation, never mind the age of the universe itself.

Many Christian sects do not claim literal truth for timescales in Genesis. Some do though, most notably fundamentalist organisations such as Answers in Genesis. Their claims have been widely refuted.

Immutability of species

Evolution has been under debate for a long time. Charles Darwin most famously put together the best (at the time) qualitative reasoning for evolution, but he was building on (or reacting to) previous ideas, and his initial ideas have of course been superseded in many ways. With modern work in breeding and DNA, this is very obviously false. We can crossbreed within a species to produce incredible diversity, and we can directly modify DNA with sequences from other species. More profoundly than that though, we do even have examples of genuine speciation taking place in the wild. In spite of this proof, many Christian fundamentalist sects still claim that species were created by God and are immutable.

But disproving religious dogma does not necessarily make a difference to belief

Fundamentalists generally deal with this cognitive dissonance in one of two ways. Some view this evidence as a test of their faith - since the real world conflicts with their faith, the real world must be at fault. And some simply claim that the people giving them proof of what happens in the real world are lying, without attempting to give any counter-reasoning or do any work themselves - they simply prefer to be ignorant than find they have been wrong. Either way, whilst disproving their views might limit the numbers of people joining them, it rarely persuades anyone to leave the group.

So whether it's true or false, it doesn't make a practical difference to them.

And modern sects have moved away from this entirely

The Catholic Church has developed a more nuanced view on this. Faced with the inevitable truth that science will discover things which contradict Biblical doctrine, they have adopted the view that the Bible should tell us how to live and not how life was created, to paraphrase Pope Francis. Most major sects have either followed a similar path, or indeed (as with many original Protestant sects) were founded largely by disagreeing with this kind of doctrinal viewpoint.

This is an important development in religion. It allows them to circumvent any issues of testability, because what truly matters with any religion or philosophical movement is whether it helps to provide its followers with a moral code to live a better life.

I'm not sure of the angle you're coming from with this question but I'll answer it as I understand it.

Yes, some do purport to make 'predictions' in the name of Christianity. Most would be described as 'cult' leaders and discredited.

This should not be surprising to Christians, as Jesus said "many will say... ‘Lord, Lord, did we not prophesy in your name and in your name drive out demons and in your name perform many miracles? Then I will tell them plainly, ‘I never knew you. Away from me, you evildoers!" - Matthew 7:22,23

Whether or not a prophecy or prediction made by an individual in modern times proves to be true is no indication of its source. That is to say, a prediction coming true does not mean it is from God. Jesus didn't say that these 'evildoers' would be crying out "did we not try to prophesy" - they would claim that they did, and he still said he would disown them.

Most Christians concerned with prophecy focus on the those recorded in the Bible and look for their fulfilment, and are not looking for individuals making claims of 'new' prophecy.