Human analysts bring to bear background knowledge, rules of thumb, contextualized reasoning, flexible assessments of similarity, and dynamic information gathering to identify and counter cyber attacks. But we are easily overwhelmed by data. Machines can quickly look for known attack signatures in large volumes of data, but are myopic and easily fooled by adversaries that introduce syntactic variations of old attacks or invent new types of attacks. We are designing a more semantic approach to cognitive cyber security that integrates diverse information sources and reasons about attacks like humans, and to leverage hardware acceleration at key points to scale up information integration to the enterprise and beyond.