[*]│Proposition│Name of │Inference │Principle │symbolized │Process │symbolized │involved ───┼───────────┼─────────────┼───────────┼───────────────────────── A │All S is │Opposition │Some S is │What is said of _all_ may │ P[†] │ │ P (I) │ be said of _some_. │ │ │ │ │ │Obversion │No S is │Two negatives are │ │ │ not-P (E)│ equivalent to one │ │ │ │ affirmative. │ │ │ │ │ │Conversion by│Some P is │An undistributed term │ │ Limitation │ S (I) │ cannot be distributed. │ │ │ │ │ │Contraversion│No not-P │Same principles which │ │ │ is S (E) │ obtain in obverting │ │ │ │ A and converting E. ───┼───────────┼─────────────┼───────────┼───────────────────────── E │No S is P │Opposition │Some S is │What is said of _all_ may │ │ │ not P (O)│ be said of _some_. │ │ │ │ │ │Obversion │All S is │Two negatives are │ │ │ not-P (A)│ equivalent to one │ │ │ │ affirmative. │ │ │ │ │ │Simple │No P is S │Distribution not │ │ Conversion │ (E) │ affected. │ │ │ │ │ │Contraversion│Some not-P │An undistributed term │ │ │ is S (I) │ cannot be distributed. ───┼───────────┼─────────────┼───────────┼───────────────────────── I │Some S is P│Opposition │Doubtful │None. │ │ │ │ │ │Obversion │Some S │Two negatives are │ │ │ is not │ equivalent to one │ │ │ not-P (O)│ affirmative. │ │ │ │ │ │Conversion │Some P is │Distribution not │ │ │ S (I) │ affected. │ │ │ │ │ │Contraversion│Impossible │None. ───┼───────────┼─────────────┼───────────┼───────────────────────── O │Some S is │Opposition │Doubtful │None. │ not P │ │ │ │ │ │ │ │ │Obversion │Some S is │Two negatives are │ │ │ not-P (I)│ equivalent to one │ │ │ │ affirmative. │ │ │ │ │ │Conversion │Impossible │None. │ │ │ │ │ │Contraversion│Some not-P │Same as in obversion of