Acting without thinking may lead to disasters. Please Explain

I think that the quote is speaking to the idea that
individuals should think carefully before acting.  The quote articulates a notion of
instances when people act without thought that result in disastrous ends.  Without
thought, action is not deliberately thought to any end.  Both the process of thought and
its end product is absent when there is not much in way of thought.  I think that this
is where the quote is directed.  It becomes essential for thought to be present. 
Individuals who are able to think and reflect are able to consider that their actions
might avert problems or disasters.  In thought, consequences are considered.  In
thought, a sense of what will happen afterwards is considered.  When there is not this
thought present, there is a lack of understanding about what could result from action. 
The quote is making clear that thought, reflection, and a sense of surmise must be
present in action.  This is needed in order to avoid miscalculation that can result in
disastrous consequences and difficulty that might result from those decisions where
thought has been absent from the decision making process.