What, according to Kant, is substance?

The paper should answer a simple question “What, according to Kant, is substance?” based on the reading that attached. Only cite from the reading and the the Internet Encyclopedia of Philosophy or the Stanford Encyclopedia of Philosophy. 

1200 words, 12pt Times New Roman font, double-spaced, 1 inch margins 

Each prompt should be answered by returning to and carefully reading the text. You are free to consult the primary text from which a reading selection was taken, but you are highly discouraged from consulting any other material. If you need clarification, feel free to search the Internet Encyclopedia of Philosophy or the Stanford Encyclopedia of Philosophy. Note that whatever you look at, you must cite. Even if you don’t cite it in the essay itself, then at least include it on the works cited page. 

Note about style & citing primary sources: you are required to cite all of your sources, including the primary text that your chosen prompt directs you to write on. Thus, if you are writing on Plato, you must cite the Plato excerpt in Reality when necessary (or, if you’re relying on the primary source excerpted in Reality, that primary source). If you use sources other than Reality (or the respective primary text), you must also include a works cited page. The citations and works cited page should follow an American English style guide. This can be MLA, APA, or Chicago. I don’t care which. I just care that it follows some style guide.