SUPPOSITION THEORY was a branch of medieval logic that was probably
aimed at giving accounts of issues similar to modern accounts of
reference , plurality , tense , and modality , within an Aristotelian
context. Philosophers such as
John Buridan ,
William of Ockham
* 1 Supposition proper * 2 Modes of supposition * 3 Ampliation * 4 References * 5 External links
Supposition was a semantic relation between a term and what it is being used to talk about. So, for example, in the suggestion Drink another cup the term cup is suppositing for the wine contained in the cup.
The logical suppositum of a term was the object the term referred to.
(In grammar, suppositum was used in a different way). However,
supposition was a different semantic relationship than signification.
Signification was a conventional relationship between utterances and
objects mediated by the particularities of a language. Poculum
MODES OF SUPPOSITION
Personal supposition was further divided in types such as discrete,
determinate, merely confused, and confused and distributive. In 1966
T.K. Scott proposed giving a separate name for
When I say I want to buy a cup I've made an indefinite affirmative claim, with cup as the predicate term. Further cup is a common term, including many particular cups within it. So if I "descend to particulars" I can re-phrase my claim as I want to buy this cup or I want to buy that cup, or I want to buy that other cup - and so on for all cups. If I had an infinite disjunction of all particular cups, it could stand in for the term cup, in its simple supposition in I want to buy a cup. This is called determinate supposition. That is when I say I want to buy a cup I mean some determinate cup, but I don't necessarily know which one yet. Likewise if I say Some cup isn't a table, I could substitute This cup isn't a table, or that cup isn't a table or ...
On the other hand, if I say No cup is a table, I don't mean This cup isn't a table or that one isn't a table or ... I mean This cup isn't a table, AND that cup isn't a table, AND that other cup isn't a table, AND .... Here I am referring not to a determinate particular cup, but to all cups "fused" together, that is all cups "confusedly." This is called confused and distributive supposition.
If I say This cup is made of gold I cannot descend to a disjunction of particulars, or to a conjunction of particulars, but only because this cup is already a particular. This kind of personal supposition is called discrete supposition.
However, the predicate of a universal affirmative claim won't really fit any of these models. All coffee cups are cups does not imply All coffee cups are this cup, or all coffee cups are that cup, or ..., but still less does it imply All coffee cups are this cup, and all coffee cups are that cup, and .... On the other hand, if it happened to be the case that there was only one coffee cup left in the world, it would be true that All coffee cups are that cup, so I can validly infer from All coffee cups are that cup, to All coffee cups are cups. Here descent to disjunction fails, and descent to conjunction fails, but "ascent from particulars" is valid. This is called "merely confused supposition."
That is basically how the theory works, a much thornier problem is exactly what the theory is for. Some commentators, like Michael Loux, have suggested that the theory of ascent and descent to particulars is intended to provide truth conditions for the quantifiers. T. K. Scott has suggested that the theory of supposition proper was designed to answer the question What kind of thing are you talking about? but the theory of personal supposition was aimed at answering the question How many of them are you talking about? Paul Spade has suggested that by the 14th century the theory of modes of personal supposition wasn't aimed at anything at all anymore.
When I say No cups are made of lead, cups supposits for all the cups that exist. But if I say Some cups were made of lead in Roman times, cups cannot just be suppositing for all the cups that exist, but for cups in the past as well. Here I am expanding the normal supposition of the terms I use. Peter of Spain says " Ampliation is the extension of a common term from a lesser supposition to a greater one." In practice, if I speak of the past, or the future, or make a modal claim, the terms I use get ampliated to supposit for past things, future things, or possible things, rather than their usual supposition for present actual things. Thus, ampliation becomes the medieval theory for explaining modal and tense logics within the theory of supposition.
* ^ Marcia L. Colish.
* Peter of Spain Summaries of Logic, Text, Translation,
Introduction, and Notes by Brian P. Copenhaver, Calvin G. Normore,
Terence Parsons, New York, Oxford University Press, 2014.
* Bos, E.P. (ed. 2013),