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:
Hindu_philosophy

Context:
Hindu philosophy also includes several sub-schools of theistic philosophies that integrate ideas from two or more of the six orthodox philosophies, such as the realism of the Nyāya, the naturalism of the Vaiśeṣika, the dualism of the Sāṅkhya, the monism and knowledge of Self as essential to liberation of Advaita, the self-discipline of yoga and the asceticism and elements of theistic ideas. Examples of such schools include Pāśupata Śaiva, Śaiva siddhānta, Pratyabhijña, Raseśvara and Vaiṣṇava. Some sub-schools share Tantric ideas with those found in some Buddhist traditions. The ideas of these sub-schools are found in the Puranas and Āgamas.

Question:
Which Hindu philosophy concerns dualism?

Sāṅkhya