Bhagavad Gita Chapter 7 - Jnana Vignana Yoga - Sloka 4

The entire content of this mail is from Swami Chidbhavananda's translation of The Bhagavad Gita, published by Ramakrishna Mission.

Prakriti - Low and High - 1-7

1 Gita Sloka  every day - Chapter 7 - Jnana Vignana Yoga - Sloka 4

Bhumih apah analah vayuh kham manah buddhih eva cha I

Aham karah iti iyam me bhinna prakritih ashtadha II Sloka 4

भूमिः आपः अनलः वायुः खं मनः बुद्धिः एव च ।

अहंकारः इति इयं मे भिन्न प्रकृतिः अष्टधा ।। श्लोक ४

Earth, water, fire, air, ether, mind, intellect and egosim; thus is my prakriti divided eightfold. 

An element is defined in one way by the modern science and in quite another way by the Indian system of philosophy. According to the latter the five senses of perception are the means to take cognizance of the elements. The ear perceives sound which is characteristic of ether or Akasa. The skin all over the body is endowed with the sense of touch which is peculiar to air. The eye cognises form revealed by light or form. The tongue experiences the taste of things dissolved in water; but for the aid and agency of water nothing can be tasted. The nose contacts smell produced by the earth.  These five instruments of knowledge are thus recognised as the revealers of the five elements, of which the world is constituted. 

The faculty of feeling is designated as the mind. The intellect is that which distinguishes the good from the bad, the agreeable from the disagreeable. That which creates the sense of agency is the egoism, without which action is impossible. The individuality of one is based on the peculiarities of these three internal organs.

The eightfold prakriti  mentioned here is elaborated into twenty four categories by the sankhya system of philosophy.