When I smoked frequently (in college) I happened to be thinking a lot
about spirituality at the same time, and I came up with some hypotheses
about the morality of what I was doing: 
  To begin with, I was influenced by Lacan's view of the subconscious:
that it is created by the difference between the speaker and the speaker's
place in the language structure. 
  In terms of spirituality: I personally believe the concept of God exists
as a cultural idea that appeals to subconsciousnesses of groups of people. 
That is why it is vague: because the subconscious impulses that create God
aren't fully understood in th e language structure. 
  Now if the subconscious is also the place to which spirituality appeals,
then to study your spirituality you must study your subconscious. 
  I believe that smoking marijuana can help you study your subconscious. 
Here's why: language is what creates meaning, and the subconscious is that
which is not expressed through language.  When one smokes, one is
temporarily distanced from the language structure.  ( That's why it can be
easy to confuse someone who's high: because they can't deal with your
words, or use their own words, as effectively.  That's why music, visuals,
and -- my favorite -- *thoughts* are more interesting: because when you
are high, the stimuli to which you are exposed will be understood not only
within the context of the language structures through which they are
usually understood: when you are high, they are understood also within the
context of your own personal non-langua ge subconscious impulses.  That's
why your smoking experience depends so much on your environment: your
state of mind depends on what your subconscious is giving it: if you feel
threatened, your subconscious will give you threatening impulses. )
  I personally believe that the best way to worship God is, rather than
asking for favors or forgiveness, to try to understand God.  One can do
this by praying in a church, by talking to a minister, by singing praises,
by analyzing the concept of God inte llectually, or, if my hypothesis is
correct, by trying to understand your subconscious connections to God,
while smoking. 
  So smoking marijuana could help you understand God not in a traditional
unquestioning way, but also in a personal, contemporary, and very living
way: by helping you understand exactly what "God" is, in your mind.  This
isn't to say, of course, that mari juana can't be abused or overused.  But
if used correctly, it could make the concept of God more real than if you
hadn't lit one up. 
  Parts of the above argument could also help explain why the strength of
the cultural idea that smoking marijuana is wrong:  individualism may be
treasured among the concepts of America, but a lack of accountability to
society is not.  If smoking does mo ve you away from the structured order,
then that is a very real threat to that structured order.  I myself wonder
if it would be good for the world as a whole to have a large segment of
the population spending their time in isolated introspection *without *
having a productive goal for that introspection.  I.E. if you sit around
smoking up and watching TV *all the time*, is that really -- from a moral,
ethical perspective -- good? 
  If, however, you use smoking as a tool for helping you understand the
world, your thoughts, your approach to things, even God, *and* make an
effort to relate what you've understood to the social structure when
you're done, then I believe that smoking ma rijuana is not only morally
benign, it is morally laudable. 
  So go ahead.  Smoke a joint for Jesus.  :)