Bis-millah,
@ Ben Sinner
Actually, one main characteristic of the Creed of pagans stems back to this principle:
They say God is a body or dwells/dwell-ed in a body or bodies.
I think the original question can be worded a different way or you may run into a Hindu who might ask you:
If God manifested Himself as Jesus (incarnate) - which is flesh [a limited creation] then couldn’t He also incarnate Himself in the form of Brahma or all the other ‘million’ forms * that Hinduism adheres to?
To say that God can only be manifested in 3 Persons is not based on rationality alone [and this is what the Hindu desires your answer to be based upon] because the question of ‘why only 3 and not 4, 5, 100, 300 as well?’ will be asked by the Hindu and because he doesn’t believe in the bible.
Then you would have to get into the discussion as to what attributes does a thing must have in order to prove that it** ISN’T God?** Besides their must be a rationality why you don’t think God is, lets say, the sun, a house, a car, a tree or a statue sitting inside of a museum etc [these all have the same attributes and characteristics.] If not, then you have destroyed the use of rational argument to disprove the pagans Creed because you have allowed finiteness, limits etc to be allowed or applied for you and not for them; hence the question by the Hindu in the beginning. [in the re-worded question].
If the question can be dealt with in a consistent way without self contradiction then that is the right direction. However, if you share the same principle [mentioned above] with paganism then the same questions addressed to the Hindu could also be addressed to you as well.*