On the one hand, it is true that perfectly disinterested activity, knowledge, and love lead to liberation. On the other hand, evolution is entirely different in each of the paths. One can move from one path to another and reach the higher path if, on the way, grace abundantly intervenes. For everything depends upon the degree to which grace is granted. Thus, in the lower path grace smooths the way with delicate touches. Already stronger in the path of the energy, grace clarifying the intelligence so that it becomes intuitive and penetrating insight. In the higher path, a very intense grace arises from the depths of the Self, from the intimacy of the soul. The effect is such that grace diffuses throughout the entire person, who is consequently exalted. But in the Essence exempt from paths (anupaya) grace no longer exists; glory alone reigns.
According to Abhinavagupta, intense grace stems from the word of the guru; average grace, from the word associated with intuition, and from faith in the scriptures. With the help of these three elements, together or separate, "the clouds of doubt vanish and we touch the feet of the All-Powerful, who is like the sun which dissipates darkness and whose glorious splendor shines in the firmament of the Heart." (T.A. II., 49)
Thus, from grace come the characteristics of the paths, the initiations, the nature of the practices, the efforts, the procedures, the duration of one's progress, the more or less definitive conquest of objectivity, and the ensuing liberation.
Thus, he who follows the individual path reaches sovereignty only after death, when he is free of misunderstanding. For while he is not ignorant of his power, because of the residues of ignorance before death, he still identifies with his body in the course of his activities (although not during samadhi). However, he is no longer a victim of illusion, for he has recognized his own essence, like the man who, having discovered the secret of a magic trick, is no longer fooled by it, even as he watches its performance. 
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He who progresses along the path of the energy, by applying himself to mystical practices (bhavana), recognizes his identity with the Lord, with his own body, and with all that exists. He revels in the divine qualities of this life, but he does not experience its fullness, for he will completely realize the universal Self only after the dissolution of the body, when the limitations of the body and the breath disappear. 
Differing as they do in general orientation, in the goal pursued, and in the effort undertaken, a comparison of these paths will underscore the unique elements of each towards deliverance – the freedom of great space, the Bhairavian immensity.
Let us imagine a dense forest that hides the sea, and several individuals whose desire to reach the sea varies in intensity. The man of action has heard about the ocean and makes great efforts (yatna) to clear a path in the forest, all the while forgetting his goal. Thus, he tries several tracks, cuts down trees, jumps over ditches, goes around obstacles, retraces his footsteps. He is pleased by the footpaths he has opened; he stops for a while, and then courageously moves on. Finally, his thoughts calm, and having found a more direct path, he can either rest, happy and assured, or continue on and enter into the path of knowledge.
The man of discernment gives himself to the cognitive energy. He searches for a good path, hesitating at the crossroads; he moves from one fork in the road to the next toward the sea, which he glimpses more and more clearly. If he meets a true guide, he will no longer lose his way. He slowly acquires the experience necessary for informed choice and clear thinking. Henceforth, he moves forward with zeal and ardor (prayatna).
The superior path of Siva involves a simple, pure intention. The traveler of this road is the impatient and intrepid being who sees the ocean from the top of a hill and moves unwaiveringly towards his goal with all his being. Without trying to discern or worry about the road, he overcomes all obstacles, guided by a single impulse – desire (udyama). Rising above himself, he is guided toward the sea and plunges into it unhesitatingly.
In the concentrated path of joy, there is no forest, there is no path; one simply enjoys the freshness and the immensity of the ocean.
Finally, in the absence of all paths, the infinity of the sea is immediately recognized, and one is completely identified with Absolute Consciousness.
Absorption in the Quintessence 
A triple absorption  corresponds to these three paths when the Lord, by his grace, merges into the heart of the yogi and the yogi merges into the Lord. Such is absorption, the key to the vault into which all paths merge.
"(The mystic) who devotes himself to absorption knows the Self to be identical with the Lord and his own energies of knowledge and activity to be no different from himself. Knowing this, he does all that he desires, even if he still resides in his body." (I.P.v. IV., 15)
Abhinavagupta states: "This absorption into Reality is the only thing that matters. Every other teaching aims only for this goal." But he later adds, so as to eliminate any ambiguity: "Upon the body's death, the Lord alone remaining, there is no longer any question of absorption: Who would one penetrate, where, and how?" 
In effect, the interpenetration of God and the soul can go so far as to mean identification. It is a matter, then, of perfect absorption, without a path or a particular way of being,  of identity with Absolute Reality.
The triple absorption is what determines the three liberating paths, according to whether one becomes absorbed in the energy at its source (the will), or in cognitive energy, or finally, in energy as it is expressed in activity.
The 34th chapter of the Tantraloka is devoted to absorption, deemed important because it was revealed by Siva himself. This short chapter includes only the following stanzas: "The moment has come to show how one enters into the Quintessence. (According to the individual path) having entered more and more profoundly into the divine state, one rests at peace, close to the Essence. Then, abandoning this path completely, one takes refuge in the abode of the energy. Finally, one arrives at the dwelling of Siva, where our own essence reveals itself quite clearly. Such is the nature of gradual absorption."
"But whoever has the good fortune to enjoy the nature of Bhairava, abundant source of the great rays (of divine energies) radiating from Consciousness, it is independent of any Path that he will finally become immersed into his own eternal Self, imbued with universal Essence."
"There, we have absorption into the Quintessence as the Lord has shown it to be."
According to Abhinavagupta, all ways, samadhi included, tend toward perfect absorption (called integral samyag avesana) in the course of which the Self, thought, the body, and the entire world merge spontaneously into ultimate Reality and become identified with it.
Absorption Belonging to the Divine Path
This divine absorption has only to do with one who is detached from all preoccupations,  for this being, writes Abhinavagupta, worries about nothing, and is not subject to dualistic thinking. Then, after a great awakening,  he is suddenly established in a perfect attunement with profound understanding, that is, understanding of universal, undifferentiated Consciousness. And it immediately attains its full expansion.
Such an illumination, he says, one grasps immediately and forever. Through this interpenetration of Siva and his adorer, the latter becomes identified with the supreme Essence, due to the inseparability of Siva and his highest energy. The dependent ego is annhilated in the energy of will – the source of the other energies – and even without having recourse to samadhi, consciousness is immediately absorbed in Siva in a union as spontaneous as it is unexpected. "Beyond all intellectual certitude, that which is truly worthy of being known, having blossomed in a perfectly pure heart, remains there permanently. It subjugates the knowing Subject; which is reflected in the mirror of the intelligence, and, at this moment, is gradually revealed in all its glory." (T.A.I. 172-175)
At the moment of this total absorption into Reality, the Self, thought, the body, and external objects all abandon their objective nature and become identified with the Lord. If at death this absorption is perfect, only the Lord remains.
Absorption in the Path of the Energy
The absorption achieved by concentrating (cinta) with one's heart upon some entity, without recitation, stems from the energy.
The heart presents itself here as intelligence, thought, and the feeling of "I", the respective operations of which are certitude, synthesis, and wrong conviction. Despite the illusions that it holds because of these operations, this path leads to the undifferentiated knowledge of the divine path. In fact, the purified vikalpa contains a knowledge and an activity of great intensity, although still subject to limiting conditions.
It suffices, then, to put one's energy ardently into dissolving all limitations so that the energy, pouring forth, brings up internally what one desires: identity with Siva.
This state of energy is at once differentiated and undifferentiated: differentiated because it contains distinct thoughts, and yet undifferentiated because it requires no external means such as recitation and other similar practices.
Absorption in the Path of the Individual
Absorption due to recitation, to the activity of the organs, to mediation, to the phonemes, and to concentration on the vital points is properly called "individual." (I. 170)
Abhinavagupta explains: "individual" clearly signifies "differentiated." Although this path is made of intellectual certitude which is part of dualistic thought, it also leads to the undifferentiated.
These last two absorptions are therefore directed towards the ocean of the undifferentiated, without which they would not exist.
Even if it is true that undifferentiated consciousness is not dependant upon differentiated thought, the individual path nevertheless allows attainment of the divine path's non-differentiation. For even though it begins by differentiated thought, it raises itself to the state of non-differentiation (nirvikalpa) by means of the progressive purification of thought.
Abhinavagupta gives an example of undifferentiated knowledge first in the divine path, then in the lower path:
"An expert in precious stones can evaluate a great number of stones at their true value even if they are shown to him at night and just for an instant. Such purity of consciousness is due to the practices of past lives, or to the will of the Lord, which nothing can restrain." (184-185)
A jeweler with little experience is at first ignorant of the value of precious stones; however, after repeated investigations, utilizing procedures to ascertain their true value, he finally attains undifferentiated knowledge which has no need for procedures. He is then declared an expert in precious stones." (229)
"Whoever gains access to the undifferentiated, whatever be the path that allows him to enter into Reality, by this very path will he become identified with Siva."
"A very pure heart whose light illumines the resplendent summit identifies with Consciousness, supreme Siva, because of this same light."
"Such is the true path, an expression of the eminent energy of the will, an absorption called divine, which Sambhunatha as well as his disciple Abhinavagupta experienced." (211-213)
In relation to conscious light, how are God, Self, and universal energy fused by means of the three paths? Since eternal light is nothing less than total, whatever the path followed, illumination must be the same in each of the paths; only its power, the degree of freedom attained, and its duration differ. One can therefore distinguish between a transitory state, a more lasting state, and the immutable nature of the pure Subject. Its variations reflect the way in which the mystical experience, called the "Fourth" (turiya) state, expands in the three ordinary states of waking, dreaming, and deep sleep. Having filled them completely, it alone remains, all ordinary states having ceased.
An individual of the lower path rarely discovers the Fourth state and cannot at will regain an illumination which is as elusive as a lightning flash. Despite his efforts, he cannot maintain himself in that state, either during sleep or in wakefulness (while he is absorbed in various activities). Coming out of rapture, he falls back into dispersion, objective vision regaining its control. Even though his empirical, individual consciousness is unified and calmed, it has still not disappeared. Self, energy, and Siva remain distinct, their fusion having been only momentary and therefore imperfect.
In the path of the energy, this absorption is deeper and more stable, and the mystic perceives the divine presence not only in his illuminated heart, but in all things. Soon he sees both himself and all things in Siva.
Siva, the universal energy, and his own Self fuse more and more completely as he experiences the Fourth state permeating not only the three subjective states (as in the preceding path) but throughout the ebb and flow of the universal life in which he henceforth participates. Though he enjoys the Fourth state frequently and maintains it for long periods of time, it is still only a state. At the height of the divine path, there is no longer a fourth state distinct from other states, but a single mode, pure Science being definitively recognized as the immutable Subject:  in other words, the co-penetration of Siva, the Self and the energy is accomplished.
The treatises of the Trika system always describe these paths beginning with the highest,  like a cascade of powers decreasing as they move farther from their source. If grace's intensity diminishes, the effort required of man must increase proportionately.
In the path of Siva the efficiency (virya) is that of the supreme Subject whose Consciousness is undifferentiated (nirvikalpa). Supreme, it is the source of all capacity and thus constitutes the efficacy of the mystical practice (bhavana) in the path of the energy. Later on this efficiency, lessened, becomes the power of meditation, the culmination of the path of the individual. And so it is up to the final practices of this path.
However, for the reader's convenience, we will follow the inverse order, beginning with the ordinary man who has limited knowledge. An unending series of shadows unfurl upon the bright surface of his consciousness. The commotion is such that, not even for a moment is he aware of the Self. His externalized and fragmentary experience keeps hidden from him the universe as it is in its essence; and the Lord appears transcendent, external, unreachable. He is ignorant, in fact, of the Fourth state, and of the subtle inwardness of absorption, because it is perpetually covered and veiled by the gross states of dreaming, waking, and deep sleep.