You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Materialism

Context:
The nature and definition of matter - like other key concepts in science and philosophy - have occasioned much debate. Is there a single kind of matter (hyle) which everything is made of, or multiple kinds? Is matter a continuous substance capable of expressing multiple forms (hylomorphism), or a number of discrete, unchanging constituents (atomism)? Does it have intrinsic properties (substance theory), or is it lacking them (prima materia)?

Question:
What is hyle?

matter