I understand the Chakras to be a sort of multi-level skeleton for consciousness intertwining with our physical, emotional and mental bodies. Bodies is the framework used in traditions I have studied. If “I” am something other than my physical body, then why not consider other “bodies” that are other than “I”. The chakras represent realms in which all 3 bodies are involved, dealing with different sets of issues. The lower chakras correspond roughly with Abraham Maslow’s Hierarchy of Needs.
The first chakra deals with maintaining a physical existence, staying alive.
The second chakra deals with relationships, and maintaining the species.
The third chakra is the realm of social interaction, power relationships.
The fourth chakra opens the possibility to unconditioned love’s expression.
The fifth chakra is sometimes represented as connected with “the void”, also with the “inner guru”, an opening to a deep wellspring of understanding.
The sixth chakra opens the possibility of transcending dualities.
The seventh chakra is the realm of Samadhi, subject of a separate post.
One of my teachers, Shyam Bhatnagar, described each of the chakras as having within it its own version of each of the seven chakras. “The 7th in the 3rd” refers to the energy of the 7th chakra as expressed through the 3rd chakra.
We mature through the chakras at a rate of about 6 (women) or 7 (men) years per chakra. So at age 18/21, we’re moving into development of the 4th chakra.