All men are mortal,
All trees are mortal,
∴ All trees are men.
All the propositions are A’s and consequently the predicates of each are undistributed, as A distributes the subject only. Therefore the middle term, “mortal,” is not distributed in either of the premises and thus the fallacy.
Fallacy shown by circles:
FIG. 9.
These circles indicate the correct meaning of the two premises. By them it is seen that all of the “men” circle belongs to the “mortal” circle and all of the “tree” circle belongs to the “mortal” circle, but in this case there is no connection between the “men” and “tree” circles. Thus, to say that “All trees are men,” is fallacious. We have no right to either affirm or deny the connection between men and trees. If “mortal” were distributed we would have this right as the following will make clear:
All men are mortal,
No stones are mortal,