Matthieu Houriet  <matthieu@houriet.com>
  
    gamma
      _
     | _
  1° || _  A => (B ou C)                        (hyp)
  2° |||   A                                    (hyp)
  3° ||| _ (B ou C)                             (1°, modus ponens)
  4° ||||  B                                    (hyp)
  5° ||||_ B ou (A => C)                        (4°, ou-intro)
  6° ||||  C                                    (hyp)
  7° ||||  A => C                               (2°, 6°, =>-intro)
  8° ||||_ B ou (A => C)                        (7°, ou-intro)
  9° |||_  B ou (A => C)                        (3°, disj. cas contr.)
 10° ||    A => B ou (A => C)                   (2°, 9°, =>-intro)
 11° ||    A => (B ou C) => A => B ou (A => C)  (1°, 10°, =>-intro)
 12° ||_   B ou (A => C)                        (11°, modus ponens)
 13° |_    A => (B ou C) => B ou (A => C)       (1°, 12°, modus ponens).


When I was young,
It seemed that life was so wonderful,
A miracle,
Oh it was beautiful, magical.
And all the birds in the trees,
Well they'd be singing so happily,
Oh joyfully,
Oh, playfully watching me.

But then they sent me away
To teach me how to be sensible,
Logical,
Oh, responsible, practical.
And then they showed me a world
Where I could be so dependable,
Oh clinical, oh intellectual, cynical.

There are times
When all the world's asleep,
The questions run too deep
For such a simple man.
Won't you please,
Please tell me what we've learned,
I know it sounds absurd,
Please tell me who I am!

I said --
Watch what you say,
Now they're calling you a radical,
A liberal,
Oh fanatical, criminal.
Won't you sign up your name,
We'd like to feel you're acceptable,
Respectable,
Oh presentable, a vegetable!

At night,
When all the world's asleep,
The questions run so deep
For such a simple man.
Won't you please,
Please tell me what we've learned,
I know it sounds absurd,
Please tell me who I am!
Who I am...

What will become of us?