Hi,There are some questions about how to define the [is]. Are the [is] in the following sentences different from each other? IN {What is in the mind.} ------the [is] = belongs to? because [what] is contained or surrounded by the mind.IN {What is on the mind.}------the [is] = identifies? because [what] is supported by [the mind]; and [the mind] bears / receives / suffers the [what].Could any native speaker help me?Thank you for your assistance.
The meaning of "is" is the same in both in your mind and on your mind. It identifies location (metaphorically).

Hi CalifJim,Would you be kind to let me ask the futher question? And could you tell me the understanding correct or not?1. We know [What is in the mind.] = [What the heart thinks.] , so, [what] is done by the mind or the heart; and [the mind] or [the heart] is the doer. So, in {What is in the mind. }, [What] as the property of [the mind] / [the heart]. So the meaning of [belongs to] must be with the [is]. 2. In [The book is to be read by every student.], the [is] used to the speaker to show [the book] like the property of [the book to be read by every student]. Because the speaker not makes [the book] typically have the quality to be read by every student. And just assign [the book] to a group given by the speaker. So, the [is] = belongs to a group of [the book to be read by every student] ?In {These people are all pathetic in a way, but the fat lady is most to be pitied.}, the speaker has the fat lady like the property of [the person to be pitied]. So, the [is] = belongs to a group of [the person to be pitied]?In {The play is to be held nest week.}, the [schedule] has [the play] belong to the play to be held nest week. Thank you for your assistance.