Dr. Smith ate a banana

Suppose you receive this trustworthy report:

1. Dr. Smith ate a banana.

You are now in a position to learn this additional fact:

2. Someone whose last name is “Smith” ate a banana.

But (2) does not logically follow from (1). So how do we learn (2) from the report?

Knowledge of English tells us that “Dr. Smith ate a banana” has “Dr. Smith” as the subject and that this sentence attributes eating a banana to the subject of the sentence. Assuming defeasibly that the the use of English in the report is correct, we conclude that someone correctly styled “Dr. Smith” was reported to have eaten a banana. And assuming defeasibly that the report itself is factually correct, we conclude that:

3. Someone correctly styled “Dr. Smith” ate a banana.

Knowing English, we also know that anyone correctly styled “Dr. Smith” has the last name “Smith”, so we get (2). We also know that anyone correctly styled “Dr. Smith” has a doctorate, so:

4. Someone with a doctorate ate a banana.

These are instances of the familiar fact that what we learn from receiving a report goes beyond the propositional content of the report.

The reportable and the assertible

I’ve just had a long conversation with a grad student about (inter alia) reporting and asserting. My first thought was that asserting is a special case of reporting, but one can report without asserting. For instance, I might have a graduate assistant write a report on some aspect of the graduate program, and then I could sign and submit that report without reading it. I would then be reporting various things (whether responsibly so would depend on how strong my reasons to trust the student were), but it doesn’t seem right to say that I would be asserting these things.

But then I came to think that just as one can report without asserting, one can assert without reporting. For instance, there is no problem with asserting facts about the future, such as that the sun will rise tomorrow. But I can’t report such facts, even though I know them.

It’s not really a question of time. For (a) I also cannot report that the sun rose a million years ago, and (b) if I were to time-travel to the future, observe the sunrise, and come back, then I could report that the sun will rise tomorrow.

And it’s not a distinction with respect to the quantity of evidence. After all, I can legitimately report what I had for dinner yesterday, but it’s not likely that I have as good evidence about that as I do that the sun will rise tomorrow.

I suspect it’s a distinction as to the kind of evidence that is involved. I am a legally bound reporter of illegal activity on campus. But I can’t appropriately report that a violation of liquor laws occurred in the dorms over the weekend if I know it only on the basis of the general claim that such violations, surely, occur every weekend. The kind of evidence that memory provides is typically appropriate for reporting, while the kind of evidence that induction provides is at least typically not.

Interestingly, although I can’t appropriately report that tomorrow the sun will rise, I can appropriately report that I know that the sun will rise tomorrow. This means that the reportable is not closed under obvious entailment.