Dissociating Thoughts and Actions

I often wonder whether the depravity of a thinker's life - be he a Descartes or a Pierce, a Berkeley or Bacon - I wonder whether their depravity incriminates their thinking. As a sort of existentialist, I must confess that I'm convinced of the indissoluble unity between thought and action; but as an elitist (and a principled one, to be sure), I also think that that kind of reasoning is just an easy way to discredit an unappealing argument - in fact, such reasoning is only employed to discredit those people who make really good arguments.