What is semiotics, and is it religiously forbidden or does it have reservations?

Alchemy [al-Sīmiyā’] is a type of magic, and it is forbidden to learn or propagate it. It is a science that combines earthly properties, liquids, or special words, creating specific illusions for the five senses. These may have a real existence or be mere imagination. It robs one of sound thought, making a person's state akin to that of a sleeper, and it specifically affects the one for whom it is performed. Al-Dhahabī mentioned that magic, alchemy [al-Sīmiyā’], chemistry [al-Kīmiyā’], and charlatanry are among the sciences that are forbidden to learn or propagate.