Good questions! I will do my best to share some helpful ideas.
happiness is to be w/God but everything’s happiness is the completion of its form -but God is not the form of humans so how could God be mankind’s last end and what place does reason (man’s form) have in human happiness?
Reason is essential to man’s happiness. Our union with God is called by many saints as the “contemplation” of God’s essence. What is contemplation but the action of a loving reason, or of a rational love?
I think this concept of contemplation of God unites two things that are two of the summits of human existence: to study and understand something that truly interests us (particularly that moment when we go “Ah! Now I get it!”) and to look at and be with someone we love.
You are right in that God far surpasses the happiness that nature would make us expect. On the other hand, there is also in our nature a deeper longing for something that surpasses even the best natural goods. We are never truly satisfied deep down (ok, apart from a few moments); God answers this deep thirst for something ever greater, which is nothing else than our desire for God. St. Thomas Aquinas speaks of man as having a natural disposition for grace.
I think that reason is somehow constitutive of man’s happiness and if that is true, then why should some use of reason be immoral -like conniving or cunning or being too forthright?
These are very limited uses of one’s reason. They concern merely the choice of means to an end; but a truly rational person also uses his reason in setting the ends for his actions.
So, a thief may be rational in planning his robbery; but the choice to be a robber is irrational; he is putting the good of the material goods he will get before the necessity of earning them. He wants to be a leech living off other people’s achievements, without ever achieving anything on his own; a choice with deep implications on his spirit and, probably, on how he sees himself. Most criminals feel guilt and shame over their crimes; a proof of how even they know they are make poor choices, running away from the happiness that could be theirs in return for a perhaps easier, but less satisfying, existence.
Someone who is cunning and conniving treats other people as means, tools, to his own designs. He will never (unless he changes) see the value of other people. He is closing himself to some of the best things in life.
Being too forthright; sometimes that may be wrong, as when we put some small goal before our respect for the dignity of others. However, I can see a forthright attitude as being virtuous too. A forthright person does not let the whims of others dictate his own pursuit of values.
