Aham, the Heart of Śiva

AHAM -sanskrit अहम् -english I -, the heart of Śiva.. To manifest means, by definition, to appear or become evident – which implies the perceiver and perceived. Consciousness becomes visible to itself as subject (Aham = I) and object (Idam = this). These two aspects of consciousness appear simultaneously and are eternally related. I am this. The subject (Aham) is said to become aware of itself in relation to its object (Idam). Sadasiva Tattva accounts for the Will aspect of Sakti – it is the condition that precedes any determinate action. It is destructible, and therefore not eternal. As the first evolute produced in the process of the evolution of consciousness, it is the last evolute dissolved in the involution of consciousness.

Siva Tattva is the first factor in the process of cosmic evolution. Consciousness in this condition is called Cit (there is no English equivalent for it) – the static aspect of consciousness in the manifest world. The Siva Tattva accounts for the Subject (Aham) of dual relationship of universal manifestation – it is the subject, knower, experiencer. It is pure consciousness – the ideal universe of perfect equilibrium has vanished and consciousness has begun to stir. It is dependent upon the active aspect of consciousness to bring it into being.

Sakti Tattva is the second factor in the process of cosmic evolution (“sak” = to be able, to be capable of). It is the kinetic aspect of consciousness. It accounts for the Object (Idam) of the dual relationship of universal manifestations. It is the universal stream of consciousness that brings all things into being and destroys all things at the end of each cycle of time. It it the universal energy that brings all things into being, and as such is considered as the feminine aspect of Nature, the Mother of the universe.

Sakti it said to have three principle modes that follow in logical succession: the power of will (Iccha); the power of knowledge (Jnana); the power of action (Kriya).

Interesting article on Wikipedia: Aham (Kashmir Shaivism)

Aham, a concept of Kashmir Shaivism, is defined as the supreme heart (hṛdayam), transcendent Self, supreme I awareness or infinite consciousness.The space of Aham is where kechari mudra (free movement in the space of the heart) is realised.
Kechari mudra is considered the supreme state of spiritual evolution.

Substrate of creation

When Śiva wants to create, the first step is said to be the creation of an interior space (the space of his heart) - a matrix of energies that will be the substrate of the new world. This place is called Aham which means "I" in Sanskrit.
Thus the absolute first creates the divine person, Aham, and from this divine person will appear the manifestation itself.

Aham is identical to mātṛkā (the wheel of phonematic energies), essential nature of all categories from Pṛithvī tattva (earth) to Sadāśiva tattva.
Aham is the final resting place, dwelling place, abode of all beings, receptacle of the world.

Ultimate mantra

Another definition of Aham is that of primordial mantra, transcendental mantra, the so called heart-bīja (mantra of the heart) - force and power of consciousness. As the supreme mantra, Aham is closely related to matravīrya (the potency of mantra).
Thus the realization of Aham confers power over any mantra.

United form of Shiva and Shakti

In Aham, the supreme (para) aspect of Śakti is realized. Aham is the Śakti of Śiva or in other words, the expansion of Śiva.
Another way of describing Aham is as the union of Śiva and Śakti, the emittive (visarga) aspect of the Supreme (anuttara).

Etymology

Aham is formed of A+HA+M, a triad of Śhiva (A), Śakti (HA) and bindu (M). M is the final point, union of Śiva and Śakti, where they dissolve into Paramaśiva. The triangle of A+HA+M is the essence of the Trika system.
A+HA+M form the sṛṣṭi bīja (seed of emission), a mantra that is identical to the energy of expansion and creation.

Aham can also be defined as: A = abedha (non-differentiation), HA = bheda (differentiation) and M = bhedābheda (differentiation cum non-differentiation).

Maha, the mirror image of Aham

On the other hand, MAHA, mirror image of AHAM, is formed of MA+HA+A, and represents the saṃhara bīja (seed of reabsorption) - the mantra that is identical to the process of spiritual evolution, or in other words reabsorption of the manifestation back into the absolute.
In MAHA, Śakti (HA) enters bindu (M) (the limited being) and reunites it with the Supreme (A). Related link: Il cuore nello Shivaismo tantrico