So oft it chances in particular men / That for some vicious mole of nature in them, / As in their birth, wherein they are not guilty, / Since nature cannot choose his origin, / By their o’ergrowth of some complexion, / Oft breaking down the pales and forts of reason;
Act I, Scene 4 · Hamlet
Context
Continuing his speech about Denmark's reputation for drunkenness, Hamlet begins a long philosophical reflection on how a single flaw can ruin an otherwise virtuous person's reputation.
Analysis
The metaphor of a 'vicious mole' describes an inborn defect as a tiny blemish that nonetheless spreads corruption, while 'pales and forts of reason' imagines rationality as a defensive structure under siege. Hamlet's clause 'wherein they are not guilty' introduces a troubling ambiguity: if a flaw is inborn and therefore not the person's fault, can they really be judged for it? This question will haunt Hamlet's own hesitations—he will later struggle to act decisively, unsure whether his nature or his circumstances are to blame.
Essay Tip
Use this to argue that Hamlet's delay isn't just plot—Shakespeare plants the concept of 'inborn defect' here so that Hamlet's later inaction can be read as something he believes he cannot help, a tragic limitation rather than a moral failure.