   In addition to the faculty of estimation, and akin to it in being innate and spontaneous, Avicenna recognized, with Aristotle, a faculty of intuition (hads) that is the key step in obtaining certain knowledge. This is the ability a person has to discern suddenly the middle term of a putative syllogism, the proposition that anchors a particular  argument.[33] Avicenna recognizes that occasionally brilliant individuals exist whose intuitive sense is so innately strong that they can do without much prior experience, empirically or rationally. In extreme and rare cases, there are individuals, like the prophets, with a developed intuitive acumen, dhakâ’ (Aristotle's anchinoia), that enables them to know instantly the entire subject matter of a given science. While not part of his normative epistemology, Avicenna attempts to accommodate this phenomenon scientifically, seeing it not as an innate power of an internal sense, but as an expression, however rare, of the emanative powers of the Agent Intellect.