Overwhelmed by complexity people look for single causes to explain why the unexplainable has occurred. For example, since the 2016 US election the Democratic Party has blamed Russia for the horrible defeat of its chosen candidate (despite the absence of verifiable evidence — and a myriad other contributory reasons). Oversimplifications such as this differ from Ockham’s razor — a problem-solving heuristic — that “among competing hypotheses, the one with the fewest assumptions should be selected” which privileges evidence over assumptions and less assumptions over more.
Faced with complexity the dark side of human intelligence pushes back: latching onto ideologies, conspiracy theories and other biases rather than expending the effort on thought (D.Snowden). Hoodwinked by our biases people settle on a comforting explanation “which almost always is a great oversimplification” (G. Klein). The problem is as acute in business as anywhere:
“…many executives, despite their good intentions, look in the wrong places for the insights that will deliver an edge. Too often they reach for books and articles that promise a reliable path to high performance. Over the past decade, some of the most popular business books have claimed to reveal the blueprint for lasting success, the way to go from good to great, or how to craft a fail-safe strategy or to make the competition irrelevant.” 
Executives buying the illusion of predictable outcomes in an unpredictable world are falling prey to simplistic casual explanations. Success in the business world “is the result of decisions made under conditions of uncertainty”  and requires us to resist “the hyperbole and false promises found in so much management writing . Business strategists” Rosenzweig suggests “would do far better to improve their powers of critical thinking”.
“We don’t see the world as it is, we see it as we are” (Anaïs Nin)
Yet humans are selective in what they see and pay attention to. Adults have long developed a ‘schema’ (a worldview) which they add to by choosing how much importance to attach to the external stimuli we are all bombarded with. “As time goes on and experience builds up, we make greater investment in our systems of labels. So a conservative bias is built in. It gives us confidence.” (M.Douglas). We reach a point where we risk valuing comforting lies over novelty, however useful.
There are good evolutionary reasons for our biases. Subsistence living meant our primary aim was getting through each day. Finding an unexpected large food source would have been great, but in the absence of any storage capacity it was more important to find the necessary minimum not to starve each day. Therefore, we evolved to seek out the predictable and avoid failure — and 200,000 years of homo sapien evolution is hard-wired into our brains: merely knowing about our biases doesn’t make us immune to them ‘anymore than you can correct your vision by understanding how the lenses in your shortsighted eyes are flawed.’
Predictability in a more complex world is drowned out by tangled interactions that appear random and predictions about what will happen next becomes decreasingly less possible. However, in the business world we continue to see the search for predictable silver bullet solutions (“Go Agile! Go Lean! Uber-ise!”) — whereas what we need is to embrace uncertainty as an ally to work with; not an enemy to defeat.
If we can accept that we are biased we can work with this. We can practice ‘constructive uncertainty’ (H.Ross): recognising that our brains do not seek ‘best-fit’ but ‘first-fit’ responses we should open up the decision-making process to inputs from distributed (network) intelligence, especially in those moments a leader feels, for any reason, uncomfortable with the decision they are about to make. As Linus’s Law teaches us: “Given enough eyeballs, all bugs are shallow.” .
The potential for gaining new strategic advantage by accepting uncertainty in our decision-making is huge:
“learning trumps ‘knowing’, since we are learning from the cognitive scientists that a lot of what we ‘know’ isn’t so: it’s just biased decision-making acting like a short circuit, and blocking real learning [and action] from taking place.”
Unacceptable casual explanations for complex events is the pre-eminent bias we need to avoid today because they become hollow yet powerful narratives that confused or scared people hook their fears on to. They perniciously feed prejudice by becoming part of the ‘system of labels’ people adopt to make sense of their world going forward. Governments have often been accused of de-humanising an enemy as a prelude to war but the reality is more complex: nations sleepwalk into war  when populations conclude it’s the only ‘obvious solution’ to address the fears their unacceptably simple casual explanations have led them to.
We’ve never needed political, business and other leaders to embrace uncertainty as much as now.