Kantian meditation

[timelets]

All ignorance is 
      either ignorance 
               of things or 
of the 
        limits of knowledge. 
If my 
      ignorance is 
              accidental and not
                         necessary, 
it must incite me, 
               in the first case, 
to a dogmatical inquiry 
                    regarding 
the objects 
          of which 
                 I am ignorant; 
in the second, 
            to a critical 
                investigation into 
the bounds of all 
               possible knowledge. 

But that my 
       ignorance is 
             absolutely necessary and 
unavoidable, and 
              that it consequently 
absolves from the duty of 
                         all further 
investigation, 
          is a fact which 
                      cannot be made out 
upon empirical grounds —
                    from observation — 
but upon critical grounds 
                     alone, that is, 
by a thoroughgoing investigation 
                  into the primary sources of
cognition. 

It follows that 
             the determination 
                  of the bounds of reason 
can be made only 
              on a priori grounds; 
while the empirical limitation of 
                                 reason, 
which is merely 
              an indeterminate cognition 
of an ignorance that can never 
                  be completely 
                              removed, 
can take place only 
                   a posteriori.

Immanuel Kant. “The Critique of Pure Reason.”