We know three things. First, that something had, at some point, happened to the cookies in the cookie jar. Second, that there are exactly three and one half cookies missing. And third, that all traces of who-, or what-, ever had tampered with the cookie jar were gone.

Invoking the Copenhagen interpretation, we cannot know with any certainty how many cookies were in the cookie jar at any time in between when we last opened the cookie jar and now. We know that there were twelve cookies in the cookie jar three hours ago. We also know that now there are eight and one half cookies in the cookie jar. There are an indeterminate number of cookies in the cookie jar between three hours ago--or time zero--and now--time final. For example, there may have been eleven cookies in the cookie jar an hour ago. Similarly, there may have been four thousand cookies in the cookie jar an hour ago. We cannot know how many cookies are in the cookie jar unless we open the cookie jar.

So, what do we know? We know that Erwin Schrodinger stole cookies and blamed physics when the kids came calling. fucking physics.