Planets and reasoning (Mars & Ketu)
There are two kinds of reasoning deductive and inductive. The inductive reasoning is the method of finding out patterns by from a population of events, things or observations. This is the method of generalizing the observations and formulation of theories. For example when we observe that leaves of almost all plants are green, we conclude that the "leaves are green" - which is a generic statement cutting across different species of plants.
On the other hand deductive reasoning is the method of applying a theory (generalized hypothesis) on a specific event or thing and predict the outcome of the observation. In the given example above, if there is a discussion about leaves, one would assume that the leaves under discussion will be green because that's the general idea that is arrived through inductive reasoning.
The ability to reason rests with the fiery planets Mars and Ketu. We are aware of the famous dictum of Jyotish- Kujavat Ketu- which means Ketu is like Mars in many respects. Among them Mars rules the ability to analyze and solve a problem by breaking down into smaller chunks and solving them individually to reach the final solution. This is the ability to apply a generic theory on problem and find the solution (predict the outcome). On the other hand, Ketu gives ability of higher abstract mathematics, which needs one to see pattern in things and coming out of a generic idea on why things are the way they are.
Thus the ability to reason deductively or inductively comes from Mars and Ketu and this can be studied in horoscope. Most in the world have strong deductive reasoning ability and not so strong inductive reasoning. That's why to be creative and find something new out of one's observation, one need to think out of the box, somewhat like headless Ketu. From this understanding, it is evident that scientist/ mathematics should have strong Ketu influencing their intelligence for them to observe patterns which was not known before- thus inventing something new.
Ability to see patterns is also linked to the right lobe of the brain, while ability to apply theory to find solution is linked to left lobe of people. It is possible that native's under heavy Ketu's influence may do things in reverse manner, for instance using left hand more often- that's what Ketu does- reverse everything it influences.