@Alan McDougall,
Well first of all what are you referring to when you say a perfect person? I would have to agree with Xris on this one, it is possible to have a perfect person IF (and the "if" is most important) you can agree on what makes a perfect person. I'll go out on a limb and define it as simply as I can for this argument.
A perfect person is a person who does the correct thing always in any situation.
Now there are a few problems with this definition since, "does the correct thing" is such a vague statement and can be highly interpret not to mention subjective. But as soon as you say relative to a given standard, then by all means it is plausible. What is the standard though?
"c" is a correct response (subjective)
"w" is an incorrect response (subjective)
"i" is indifferent response but carries with it neither "c" nor "w" and could be listed either as being "c" or "w" or tossed out completely. (subjective)
"g" is good (this term reflects "c" and doesn't hold to any standard)
"b" is bad (this term reflects "w" and doesn't hold to any standard)
"e" is error or negotiable or unnecessary. (reflects "i" no standard)
"t" is total actions ever done, either said, thought, or acted out.
"p" is perfection
"n" is imperfection (didn't really need this because anything not perfect would be equal to "n")
c + w + i = t (total of all actions ever done)
(now we need to find out just how good they are by weighing the actions)
t/c = g
t/w = b
t/i = e
(comparatives)
If g < b then the person is more good aligned (note that g must be low number)
If g > b then the person is more bad aligned (note that g must be high number)
If e < (g+b) then the person does a lot of actions that are neither good nor bad. ??
However now here is the whole point of this little run about.
if (t/g) = t (then the person is perfect)
There are a few other ways to do this but I wanted to make it as easy as possible with the least amount of confusion. I could have made it shorter with fewer calculations but it would have been more confusing. Enough said.
This proves that if you can determine what are correct responses for every possible action then you can figure out if a perfect person is possible. (which it is.)
This also takes into consideration free will even though I don't believe free will exists.