Why did Thoreau emphasize the good qualities of prison?

I think that Thoreau would have inverted the traditional
depiction of prison in a variety of ways.  The first would have been to identify an area that is
so frowned upon in society as a realm of complete detachment and solitude.  These were profound
themes in the work of Thoreau, who suggested that the individual who is able to move themselves
away from society and achieve a sense of introspection through solitude is farther down the path
of self- realization than all others.  In this light, prison can be seen as representing good
qualities.  Additionally, Thoreau was of the mindset that individuals who listen and heed the
thoughts of their conscience might come into conflict with the authority structure.  Thoreau's
own belief in civil disobedience found him at odds with the political and legal structure.  In
these lights, prison can be seen as a testament to one's own convictions, a realm where there can
be no compromise.  If this means prison must be the end result, Thoreau would rather see this end
realized than one where an individual has to betray their own beliefs. Prison might be the only
end where one can "get right" with their own conscience and sense of right and wrong.  In this
vein again, one can see prison as possessing good qualities.