Handbook of the History of Logic: - Fordham University Faculty

250 Terence Parsons
above, allowed for immobile distributive supposition by including a provision in
the descent condition for distributive supposition for altering the wording during
descent. If no alteration is necessary, the supposition is mobile; if some is necessary
the supposition is immobile. Unfortunately, he did not specify which rewordings
preserve distribution, and which do not. For this reason, I have not tried to capture
his form of immobile distribution.
Burley also allows for immobile distribution; he says:
But confused and distributive supposition is immobile when a common
term is distributed for its supposita and one cannot descend to
those supposita with respect to that with respect to which the distribution
is made. For instance, in ‘Every man besides Socrates runs’, the
term ‘man’ is distributed with respect to an exception, and one cannot
descend with respect to the same exception. For it does not follow:
‘Every man besides Socrates runs; therefore, Plato besides Socrates
runs’. [PAL 1.1.4 para 101 (107)]
This seems to define distributive supposition in terms of whether the common term
is distributed; the supposition is then mobile if descent is possible. Since Burley
offers no account of what makes a term distributed, there is no clear doctrine here.
(But the next section may offer an answer in terms of the causes of distribution.)
Paul of Venice perhaps comes closest to capturing the spirit of immobile distribution:
Immobile distributive personal supposition is the acceptance of a common
term standing personally beneath which one does not descend;
but if one should descend, he must do so conjunctively. For example
from ‘necessarily every man is animal’, it does not follow with the due
mean, ‘therefore, necessarily, this man is animal and thus of singulars’,
because the antecedent is true, and the consequent is false. [LP II.5
(152).]
Unfortunately, Paul does not say how to tell how one should descend when “one
does not descend”.
I will continue to work with Buridan’s simpler assumption that no real distribution
is immobile; that is, I will assume that all distribution is mobile by definition.
Immobile distribution will continue to be a not-very-well-defined special
case, which is not actually a subclass of distributive supposition.
8.4 Causes of the Modes
The later theory continues the tradition of the earlier theory that modes of supposition
(other than determinate) must be caused. Since the later theory disagrees
with the earlier regarding which modes of supposition some terms have, the rules
for the causes of modes must be different. And since according to the later theory