The implicit dimension of enthymemes is investigated from a pragmatic perspective to show why a premise can be left unexpressed, and how it can be used strategically. The relationship between the implicit act of taking for granted and the pattern of presumptive reasoning is shown to be the cornerstone of kairos and the fallacy of straw man. By taking a proposition for granted, the speaker shifts the burden of proving its unacceptability onto the hearer. The resemblance (likeliness) of the tacit premise with what is commonly acceptable or has been actually stated can be used as a rhetorical strategy. © Fabrizio Macagno & Giovanni Damele.