Someone skilled in dialectical idealism: someone able to arrive at historical conclusions through consideration of contradictions.
Someone skilled in dialectical materialism: someone able to arrive at socio-political conclusions through consideration of class differences.
Someone knowledgable about dialects.
Someone skilled in dialectics: someone able to arrive at logical conclusions through reasoned argument.
A person who hypothesizes.
Any of several systems that attempt to make educated guesses from incomplete information.