Ambiguity in Conrad's Heart of Darkness: A Highbrow Response

In a recent issue of The Guardian, Sam Jordison writes on "Heart of Darkness by Joseph Conrad--a trip to inner space."  His subtitle is similarly awkward, asserting:

Only 40,000 words long, this story of colonial brutality is a mesmerisingly ambiguous voyage into the darkest parts of the soul...

My first impression is incredulity.  How is it Jordison finds the tale ambiguous, and how is it that ambiguity could be mesmerizing? What exactly is the soul, and if it has dark parts, might we expect it to have lighter regions as well? More importantly, do other people reading the story experience the same difficulties? Or, even worse, do critics and professors teach students to have these difficulties when they read the story?

 From the article:

I can also go some way towards agreeing with his [Harold Bloom's] assessment that it is Conrad’s “unique propensity for ambiguity” that makes discussing the book so fascinating. Trying to get hold of the novel’s meaning is like trying to catch smoke with your hands. The very act of describing it makes it harder to grasp – and that makes the challenge all the more enticing.

I don't see much ambiguity in Heart of Darkness. It strikes me as being a fairly straightforward adventure yarn. If anything, it could be too grown-up for modern readers, and evidently too playful.  At the crossroads of setting, plot and theme, it is a journey into the aspirations of late-19th century Euro-bureaucrats whose ambitions run amok. That is, rather than a "deep" psychological exploratory, Heart of Darkness is a dystopian story about corporate ambition, with a greasy river as a backdrop.

Compare Conrad's "An Outpost of Progress." The vision in Heart of Darkness is more intense and is rendered in greater detail. The story (and here I throw an avuncular nod at Jordison) is told in oblique terms to enhance the reader's sense of adventure and discovery, as well as to drive an aesthetically pleasing sense of verisimilitude. Meanwhile, Conrad's (version of) English chap humor and the basic "joke"--and that joke after all is the meaning--remain pretty much the same in both stories.

Jordison addresses the spectre of colonial brutality, placing this theme at the heart of the story.  Nothing new. This is a path through the critical woods that is well-trodden. Moreover, as my friend M-A Berthier puts it, the exercise of that theme is "like calling Moby-Dick an exposé of the whaling industry."  In Heart of Darkness, I see the theme of "brutality" in the terms of a broader human brutality. Conrad through his narrator Marlowe presents brutality as a fully anthropological  problem.  But of course as he reaches that conclusion, Marlowe, now back in Europe, checks himself and says his imagination was ill...  Ambiguity?  Not really.  But youth, adventure, humor, frustration, ambivalence, seeing, and seeing through many things--yes.