It seems to me that one way out of that problem is to hedge on the perichoresis claims and say that the members of the Godhead can have “maximal indwelling unity” but not really absolute perichoresis or something. That way a level of trust is still required between the members of the Godhead.

Perhaps a better argument is to lean on the idea of agent causal liberterianism and simply point out that members of the Godhead may not now intend to ever deceive or betray each other but since they are free they could at some point change their mind and intend to do so in the future. The trust they exhibit is that none will ever choose to change their intentions.

Allow me to take a stab while we wait for John to respond.

Why does trust imply the ability to do the contrary?

I think the point is that trust implies some amount of uncertainty. In your example, it is reasonable (in some sense) to say that you trust that gravity will exist in the future because the future is uncertain. It is conceivable that gravity could cease to work as you expect it to and you can’t be sure what will happen in the future.

It doesn’t make sense, I would claim, to say that you “trust” me to put up a post on the war chapters of the Book of Mormon on May 6th of this year, because you already know that I did that. There is no uncertainty, so there is no need for trust. In the example from John, trust is used in a interpersonal context, which means the example about gravity is not necessarily a perfect fit because there seems to be more going on in our trust of people than in our trust of physics.

What does the ability to do the contrary imply the lack of knowing the intentions?

John’s (3) says “If Y has the ability to deceive X then X cannot know the intention(s) of Y.” This is different than what you ask about above. It is not the ability to do the contrary that implies a lack of knowing the intentions of another person, but the ability to deceive someone that requires this.

I suppose it would be more precise to say that you cannot deceive someone intentionally if they know your intentions. This would leave open the possibility that they can deceive you to the same extent they are self-deceived.

However, this leads me to question point (2) which begins “Therefore, If X trusts Y to be honest with X.” What reason do we have to suppose that the Father must trust the Son to be honest? I don’t see any reason we must assume this, which might be a fairly big problem for the rest of the argument, as currently framed.

1. Why does Trust imply the ability to do the contrary? (Example: I trust Gravity to exist on earth because it always has existed.)

2. What does the ability to do the contrary imply the lack of knowing the intentions? (example, I trust my watch to tell time. MY watch may have the ability to not function, this does not imply I do not know the intentions of my watch)

I’ll stop there for now

That is an interesting point, I’ll be curious to read Blake’s response.

Incidentally, if the email address you listed is your real email, I am very impressed you were able to get it :)