alright, so can you go ahead and explain how the Trinity is indeed logically coherent?

https://www.youtube.com/watch?v=H_WPuPdFsIg
Here is this video for reference.

To me, the Father is what people usually mean when they think of the omniscient, omnipotent, Creator God. Jesus is his instantiation in human form. The Holy Spirit is the Father’s Spirit that dwells in people’s souls when they are in harmony with God’s will. They are all different manifestations of the One God. What’s the problem?

https://www.youtube.com/watch?v=H_WPuPdFsIg

@ 1:44 the following stated about the Trinity:
1. The father is God, the holy spirit, and the Holy Spirit is God.
2. The father, son and holy spirit are distinct.
3. There is only One God.

How does a person make sense of these three propositions?

They are distinct in that they manifest Themselves differently, but They all share the same essence.

The issue I have with that is if you consider the father, son and holy ghost to be only a part of God or are they all each fully God?

They are Each fully God but in different forms. At least that’s my take.

Can you explain what you mean by "different forms"?
In that video i linked, the person makes a comparison to how some people may think of Superman as "Kal -el", as "Clark Kent" and as "Superman," but each is only a name for one person.

I’ll try. So, a person can be a father, a spouse, and a sibling. They are different orientations, but of one person. The essence of God is One. God the Creator (The Father) is how that essence manifested in Genesis. Jesus is how that essence manifested when He gave His Grace to all humanity in the New Testament, and the Holy Spirit is the essence of God manifesting in individual people when they are “filled with the Spirit”.

https://www.youtube.com/watch?v=H_WPuPdFsIg
@ 0:26, the video explains what modalism is and states that it is considered heretical.
Your example of how a man can be a father, husband, and brother sounds like modalism.
Do you disagree?

considered heretical by whom?

https://www.theopedia.com/modalism
Church fathers it seems.

I don’t give a fuck about Church fathers.

alright, but many Christians do consider what church fathers had to say as important though, but I am sorry for being presumptuous.

No problem. You didn’t know my mind. I don’t adhere to any given church’s dogma.

Check the chapters of the Summa I mentioned and linked to. Then get back and let's discuss it.

Perhaps a fluid model will help to make sense of the Trinity.

Three drops of water in different locations are distinct and have their own identity BUT they're ALL water.

Bring the three drops of water together and they coalesce to form ONE drop of water not 3.

I probably have an advantage over most people here, in that I have personal experience of being one man with two persons in my head at the same time. (I don't recommend it, it's horrible.) Based on that experience, I would say there's nothing logically incoherent about the Trinity.

Did you notice how this video does not actually reach a conclusion? It does not explain how the Trinity is logically coherent.

But it was quite funny. Thanks.

These divine divisions -like all partitions of reality- are only in our mind but they are handy. The Triad division in particular, implies Perfection and Creative Energy; it´s very suitable to symbolize the Origin and Continuity of the Cosmos, as you can also see in the hindu Trimurti. The personal aspect refers to a historical role of the divinity in human affairs, just like personal traits in all of us are made of a set of relationships in historic time with the social and natural world.

Firstly, perhaps the better question would have been, "who/what is God?" It may shine a light on how one God can also be represented by three distinct identities.

Secondly, if Jesus is the son, shouldn't we follow his teachings about who/how the father and holy spirit are? Didn't Jesus explain his son-hood?

Thirdly, (from the video) what is wrong with modalism? What makes it illogical (if it is)?

Modalism is a heresy. It is not illogical.

Since you brought it up, why not make the argument that you think Aquinas makes and then we can see if it is worth the time?

Again, that is modalism.

I agree if you want to reduce Jesus as only a part of God, but the doctrine of the trinity means that Jesus is not just part of God, but fully God.

In your example, a body and three persons can serve to explain partialism.

Since you brought it up, why not make the argument that you think Aquinas makes and then we can see if it is worth the time?

Said the guy who posted a video link.

Well, I watched the video. It was not worth the time. You'll have to take a chance, apparently, just like I did.

Of course, the video was only to help start a conversation.

Modalism is a heresy. It is not illogical. — Walter Pound

What about it is heretical?

If you reread what I wrote in the introduction, I never say that the video argues that the trinity is indeed illogical only that the video is a good introduction on the topic. Not even the maker of the video argues that the trinity is illogical, but you want to say that Aquinas solves the problem so please explain how he did it.

https://en.wikipedia.org/wiki/Sabellianism

I personally don't believe it is heretical, but other Christians have condemned it as such and I am just repeated their opinion on the matter.

I don't have patience for this back and forth nowadays, sorry. You should have tried it 15 years ago.

Perhaps if you can specify what is the main problem (rather than give a list or a handwave), we can pick it up and run with it. I'll do it through a link to a question to the Summa, since that's how the Summa is organized -- in a question and answer format. Your question is already answered there. It ought to be enough to prod you into checking it, but to each his own.