Can you be rational and believe in God?

It doesn't.

As long as the input data is wrong, you can even believe in invisible pink goats storming the Proxima Centauri with BFGs 9000 from Doom, and technically be rational.

If I saw such a thing I would believe it were more rational to think I was hallucinating. Surely that's the rational position. Input data has to be made coherent with the rest of our understanding of the world gained in past experiences.

Surely believing something irrational has something to do with the rationality of the individual?

But if whole input data is wrong, or a large part is wrong, while too much of the correct data incomplete, you can believe in nonsense and stay rational.
If you take a closer look into history of science, or at how some people were trying to rationalise religion a couple of centuries ago, it turnes out that they could be perfectly rational, just because some input data was wrong, and a large portion of information about the world was incomplete.

Science can now be more rational, because we have much more extensive knowledge and better tools, but back in time, some great discoveries were made because the discoverers were acting irrationally.
A hundred years ago it was rational to think that stars and galaxies should be getting closer to each other because of the gravity effect. It turns out that they're actually increasing distances between each other. Since that time, it has become rational to think there is some sort of energy, effect, or substance that causes the behaviour being opposite to the predicted one, yet, before that we had never registered anything that would explain why the increase of distances takes place.

No. There are examples of people including scientists who have strong religious views and they believe in God- they’re still rational but they’re choosing to believe in God, having faith which goes beyond logic and reason to some people.

I agree regarding science, but religious knowledge is surely different to scientific knowledge. Empirical scientific knowledge gained by unlucky data which gave a false appearance is one thing, but religious faith is not even based on any such empirical data. It's surely more analogous to those scientific views which were equally unempirical like belief in 'bad blood' to be removed with leeches etc.

Today religion is not rational.

But let me put the problem with the following example:

Data 1: Zeus exists.
Data 2: Data 1 is trustworthy because it has been spoken by trustworthy and wise men.
Data 3: Zeus has an ability to throw thunders.
Data 4: Data 3 is thrustworthy because it has been spoken by trustworthy and wise men.
Data 5: Thunders appear over the mountain of Olympus with remarkable frequency.
Conclusion: Zeus is present at the mountain of Olympus more often than in other places.

This reasoning obviously has a flaw of basing an argument on authority, but it's not irrational. Data 1-4 inform of a thing that causes thunders, and Data 5 informs that thunders hit a certain place more often than other places. Therefore, it is a rational conclusion that the thing that causes a certain phenomenon is present at a certain place.
A belief that Zeus lives at Olympus is only irrational today, because now we know that the Data from 1 to 4 is wrong.

We had to discuss this but I was kind of confused as to what to say because a person chooses to believe in God so why should that take away a persons ability to be rational?

They are rational regarding their scientific research but irrational regarding their belief in God no?

I totally believe that there is a God.

I thought rational was defined as basing your belief on evidence no?

Why? Evidence? Indoctrination? Wishful thinking?

yes of course you can

the rational economic agent does what increases their utility. belief in god makes some people happier therefore, rational

is it true in all cases that if it makes you happier then its rational?

Wishful thinking- no
Indoctrination- no
According to the Bible “The heavens declare the glory of God, and the sky above proclaims his handiwork. Day to day pours out speech, and night to night reveals knowledge. There is no speech, nor are there words, whose voice is not heard.”
**Psalms‬ *19:1-3‬ *ESV‬‬. I’ve had a religious experience, fasted and prayed feeling inexpressible joy. Also let’s be real, people are indoctrinated to an extent with ideas and attitudes which shape they think and act accordingly to societal standards whether it’s through education, culture or religious means.

No. That is Empiricism.

No. My view is that they’re not irrational due to their belief in God. Myself I’m Christian. I’m just saying that for others (atheists etc) a belief in God is irrational as ‘there is no reason or evidence for believing there is a God’. I totally believe that there is a God.

substitute happy for any instance of utility-maximising axioms, such as giving them a purpose, and yes