# CAS LX 502 Semantics 10b. Presuppositions, take 2 10.2.

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CAS LX 502 Semantics 10b. Presuppositions, take 2 10.2

Presupposition The basic intuition: The basic intuition: JOHN sang too. JOHN sang too. This sounds weird out of the blue. This sounds weird out of the blue. It’s only appropriate in certain discourses. It’s only appropriate in certain discourses. Those discourses are ones where it’s already known that someone besides John sang. Those discourses are ones where it’s already known that someone besides John sang. This presupposes that This presupposes that Someone besides John sang. Someone besides John sang.

Projection My wife left me. My wife left me. I have a wife. I have a wife. My truck broke down. My truck broke down. I have a truck. I have a truck. My wife left me and my truck broke down. My wife left me and my truck broke down. I have a wife. I have a truck. I have a wife. I have a truck. The idea is that if we take two sentences that each have a presupposition and put them together with and, it seems that the resulting sentence inherits the presuppositions of both. As a first approximation. The idea is that if we take two sentences that each have a presupposition and put them together with and, it seems that the resulting sentence inherits the presuppositions of both. As a first approximation. ps(p and q) = ps(p) and ps(q) ps(p and q) = ps(p) and ps(q)

And JOHN sang too. JOHN sang too. Someone other than John sang. Someone other than John sang. Even MARY applauded. Even MARY applauded. Mary was the least likely to have applauded. Mary was the least likely to have applauded. JOHN sang too and even MARY applauded. JOHN sang too and even MARY applauded. At the party, Bill sang, and Sue applauded vigorously, but Mary frowned and appeared to think singing was for idiots. However… At the party, Bill sang, and Sue applauded vigorously, but Mary frowned and appeared to think singing was for idiots. However… #The party was silent, but Mary wrote on her notebook that singing was for idiots. #The party was silent, but Mary wrote on her notebook that singing was for idiots. #At the party, Mary couldn’t stop applauding—she applauded when Bill sang, when the wine was opened, when the dog went to sleep, when the trash overflowed… #At the party, Mary couldn’t stop applauding—she applauded when Bill sang, when the wine was opened, when the dog went to sleep, when the trash overflowed…

Projection First approximation: ps( p and q ) = ps( p ) and ps( q ) First approximation: ps( p and q ) = ps( p ) and ps( q ) However, there is an exception. However, there is an exception. Presupposes that someone else sang: Presupposes that someone else sang: Mary danced and JOHN sang too. Mary danced and JOHN sang too. JOHN sang too and Mary danced. JOHN sang too and Mary danced. These sound weird “out of the blue” These sound weird “out of the blue” Doesn’t presuppose someone else sang: Doesn’t presuppose someone else sang: Mary sang and JOHN sang too. Mary sang and JOHN sang too. This one does not sound weird “out of the blue.” This one does not sound weird “out of the blue.” The reason seems to be that ps(q) is satisfied by p. The reason seems to be that ps(q) is satisfied by p.

What is presupposition? Presupposition is a constraint on the context in which a sentence is evaluated. Presupposition is a constraint on the context in which a sentence is evaluated. A context c might contain the fact that Bill sang. In that context… A context c might contain the fact that Bill sang. In that context… JOHN sang too. JOHN sang too. …is fine. That is, so long as c entails ps(p), then p can be evaluated. …is fine. That is, so long as c entails ps(p), then p can be evaluated. After accepting p as true, the context has changed: It now also contains the fact that John sang. It is now c+p. After accepting p as true, the context has changed: It now also contains the fact that John sang. It is now c+p.

The filtering effect of and It seems that ps(p and q) = ps(p) and ps(q) unless p entails ps(q). In that case, ps(p and q) is just ps(p). It seems that ps(p and q) = ps(p) and ps(q) unless p entails ps(q). In that case, ps(p and q) is just ps(p). We say that ps(q) is “filtered out” by and in this situation. We say that ps(q) is “filtered out” by and in this situation. But that’s kind of complicated. How could that be true? Rather, why is human language designed in such a way? But that’s kind of complicated. How could that be true? Rather, why is human language designed in such a way? But there is a quite sensible interpretation of why that happens. Why it is exactly that situation in which the filtering occurs. But there is a quite sensible interpretation of why that happens. Why it is exactly that situation in which the filtering occurs.

The filtering effect of and Mary sang and JOHN sang too. Mary sang and JOHN sang too. To evaluate p and q, we evaluate p first. To evaluate p and q, we evaluate p first. To evaluate p, c must entail ps(p). To evaluate p, c must entail ps(p). If it does, then we evaluate q. If it does, then we evaluate q. But now the context has changed. We have p now. So, the context is now c+p. But now the context has changed. We have p now. So, the context is now c+p. To evaluate q, c+p must entail ps(q). To evaluate q, c+p must entail ps(q). If p by itself entails ps(q), then it doesn’t matter what c is. No new restrictions. If p by itself entails ps(q), then it doesn’t matter what c is. No new restrictions. The only restriction on c is that it entail ps(p). The only restriction on c is that it entail ps(p). Hence: ps(p and q) = ps(p) if p entails ps(q). Hence: ps(p and q) = ps(p) if p entails ps(q). (No, that’s false. Mary didn’t sing.) (No, that’s false. Mary didn’t sing.)

Dynamic semantics The fact that the presupposition projection properties of and are so natural if we assume that p is evaluated and added to the context first (temporarily) before q is evaluated suggests that our interpretation of semantics is quite dynamic. The fact that the presupposition projection properties of and are so natural if we assume that p is evaluated and added to the context first (temporarily) before q is evaluated suggests that our interpretation of semantics is quite dynamic.

Other projection properties Simpler than filters (and, if…then). Simpler than filters (and, if…then). Sentences can be embedded within other sentences. The verb that is used to do this affects whether the presuppositions of the embedded sentence are inherited by the containing sentence. Sentences can be embedded within other sentences. The verb that is used to do this affects whether the presuppositions of the embedded sentence are inherited by the containing sentence. Pat (also) knows that JOHN sang too. Pat (also) knows that JOHN sang too. Pat realized that JOHN sang too. Pat realized that JOHN sang too. Pat (also) regrets that JOHN sang too. Pat (also) regrets that JOHN sang too. Pat thinks JOHN sang too. Pat thinks JOHN sang too. All of these kind of feel like the presuppositions are inherited, but… All of these kind of feel like the presuppositions are inherited, but…

Plugs Little Timmy has a fantastic imagination. Little Timmy has a fantastic imagination. Timmy thinks the TOASTER is magic too. Timmy thinks the TOASTER is magic too. Nothing need actually be magic for this to be evaluable. Nothing need actually be magic for this to be evaluable. Note, though, that what we do seem to presuppose here is that Timmy thinks something other than the toaster is magic. Note, though, that what we do seem to presuppose here is that Timmy thinks something other than the toaster is magic. Little Timmy is a literal-minded realist. Little Timmy is a literal-minded realist. #Timmy thinks the TOASTER is magic too. #Timmy thinks the TOASTER is magic too. Nevertheless, think has not projected the pss of the embedded sentence to the containing sentence. Think is a plug. Cf.: Nevertheless, think has not projected the pss of the embedded sentence to the containing sentence. Think is a plug. Cf.: Timmy realized the TOASTER is magic too. Timmy realized the TOASTER is magic too. Timmy discovered that the TOASTER is magic too. Timmy discovered that the TOASTER is magic too.

On depressions If there is a depression, the HANDOUTS will be destroyed too. If there is a depression, the HANDOUTS will be destroyed too. What a weird sentence—but one that, even if it is false, requires us to presuppose that something other than the handouts will be destroyed. What a weird sentence—but one that, even if it is false, requires us to presuppose that something other than the handouts will be destroyed. If there is a fire in KCB, the HANDOUTS will be destroyed too. If there is a fire in KCB, the HANDOUTS will be destroyed too. Logically speaking, the extent of the fire in KCB might be limited to the destruction of the handouts. There simply being a fire in KCB doesn’t entail rampant destruction. It’s just kind of expected. Logically speaking, the extent of the fire in KCB might be limited to the destruction of the handouts. There simply being a fire in KCB doesn’t entail rampant destruction. It’s just kind of expected. If…then is a filter like and: ps(p  q) = ps(p) and, unless p  ps(q), ps(q). If…then is a filter like and: ps(p  q) = ps(p) and, unless p  ps(q), ps(q). Well, here, p  ps(q) is false. So both ps(p) and ps(q) should project. The pss should include that something other than the handouts will be destroyed (fire or no fire). But that’s not right. Well, here, p  ps(q) is false. So both ps(p) and ps(q) should project. The pss should include that something other than the handouts will be destroyed (fire or no fire). But that’s not right.

On depressions If there is a fire in KCB, the HANDOUTS will be destroyed too. If there is a fire in KCB, the HANDOUTS will be destroyed too. If there is a depression, the HANDOUTS will be destroyed too. If there is a depression, the HANDOUTS will be destroyed too. The difference between them seems to be that under normal circumstances, there being a fire in KCB entails rampant destruction. But not so for there being a depression. The difference between them seems to be that under normal circumstances, there being a fire in KCB entails rampant destruction. But not so for there being a depression. So, perhaps: ps(p  q) = ps(p) and, unless p  ps(q) usually, ps(q). So, perhaps: ps(p  q) = ps(p) and, unless p  ps(q) usually, ps(q). That’s not very precise, though. What we really mean that if p  q is uttered in a normal context (no feeling therefore of any constraint), p  ps(q) is true. That is, rather, c+p  ps(q). That’s not very precise, though. What we really mean that if p  q is uttered in a normal context (no feeling therefore of any constraint), p  ps(q) is true. That is, rather, c+p  ps(q). In such a context, we’d expect ps(q) to be filtered out. In such a context, we’d expect ps(q) to be filtered out.

On depressions If there is a fire in KCB, the HANDOUTS will be destroyed too. If there is a fire in KCB, the HANDOUTS will be destroyed too. If there is a depression, the HANDOUTS will be destroyed too. If there is a depression, the HANDOUTS will be destroyed too. If we put the second one in an abnormal context, where there being a depression does entail rampant destruction, then ps(q) is filtered out in the second one too. If we put the second one in an abnormal context, where there being a depression does entail rampant destruction, then ps(q) is filtered out in the second one too. If it were assumed that (although it didn’t have to be true, but nevertheless is) in times of depression, professors as a class destroy all evidence of their work (so it cannot be stolen and sold on the black market), then… well, ps(q) does seem to be filtered out in the second one. If it were assumed that (although it didn’t have to be true, but nevertheless is) in times of depression, professors as a class destroy all evidence of their work (so it cannot be stolen and sold on the black market), then… well, ps(q) does seem to be filtered out in the second one. Bill is absent and JOHN drinks too. Bill is absent and JOHN drinks too. This is really just further support for the “incremental” interpretation of the filtering conditions. This is really just further support for the “incremental” interpretation of the filtering conditions.

The cancellation view Triggers yield potential presuppositions. A potential ps may or may not become an actual ps. In particular, not if it is canceled. This happens when: Triggers yield potential presuppositions. A potential ps may or may not become an actual ps. In particular, not if it is canceled. This happens when: The ps is inconsistent with assumptions in the context. The ps is inconsistent with assumptions in the context. The ps is inconsistent with one of the conversational implicatures of the matrix sentence containing the trigger. The ps is inconsistent with one of the conversational implicatures of the matrix sentence containing the trigger. If the problem has been solved, then it is Lauri who solved it. If the problem has been solved, then it is Lauri who solved it. Implicature: truth value of the problem has been solved (somebody has solved the problem) not assumed. Implicature: truth value of the problem has been solved (somebody has solved the problem) not assumed.

The cancellation view Triggers yield potential presuppositions. A potential ps may or may not become an actual ps. In particular, not if it is canceled. This happens when: Triggers yield potential presuppositions. A potential ps may or may not become an actual ps. In particular, not if it is canceled. This happens when: The ps is inconsistent with assumptions in the context. The ps is inconsistent with assumptions in the context. The ps is inconsistent with one of the conversational implicatures of the matrix sentence containing the trigger. The ps is inconsistent with one of the conversational implicatures of the matrix sentence containing the trigger. I don’t have a dog. I don’t have a dog. So at least you don’t have to walk your dog. So at least you don’t have to walk your dog. Problems here too. Problems here too. If John has twins, Mary will not like his children. If John has twins, Mary will not like his children. John has children is potentially presupposed. John has twins is implicated not to be necessarily true. Nothing blocks the presupposition from projecting, but it doesn’t. John has children is potentially presupposed. John has twins is implicated not to be necessarily true. Nothing blocks the presupposition from projecting, but it doesn’t. If John has children, Mary will not like his twins. If John has children, Mary will not like his twins. John has twins is potentially presupposed, but should be knocked out by the implicature that it is not known that John has children. But this sounds odd anyway. On a filter account, this makes sense. Having children does not entail having twins (and in an abnormal context where it does, ps(q) seems to be filtered out). John has twins is potentially presupposed, but should be knocked out by the implicature that it is not known that John has children. But this sounds odd anyway. On a filter account, this makes sense. Having children does not entail having twins (and in an abnormal context where it does, ps(q) seems to be filtered out).

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