Rather than seeing perception as an incomplete science, we must recognize that classical science is … — Maurice Merleau-Ponty

Rather than seeing perception as an incomplete science, we must recognize that classical science is a perception that has forgotten its origins; the fundamental philosophical task is to return to the lived world beneath the objective world, restoring to things their concrete physiognomy, to organisms their own way of inhabiting the world, and to subjectivity its historical inherence, by rediscovering the nascent system 'Self–Others–things' that perception originally discloses.

By Maurice Merleau-Ponty, from Phenomenology of Perception

Key Arguments

He inverts the earlier conclusion: 'We will no longer say that perception is a nascent science, but rather that classical science is a perception that has forgotten its origins and believes itself to be complete.'
He defines 'The fundamental philosophical act' as 'to return to the lived world beneath the objective world (since in this lived world we will be able to understand the law as much as the limits of the objective world),' making the lived world the ground for understanding objectivity.
This act would also 'be to give back to the thing its concrete physiognomy, to the organisms their proper manner of dealing with the world, and to subjectivity its historical inherence,' reversing the earlier abstractions of science and transcendental philosophy.
He describes this as 'to rediscover phenomena (the layer of living experience through which other people and things are first given to us, the system “Self–Others–things” in its nascent state),' emphasizing the primordial relational field.
It would further 'be to awaken perception and to thwart the ruse by which perception allowed itself to be forgotten as a fact and as perception to the benefit of the object that it delivers to us and of the rational tradition that it establishes,' identifying a 'ruse' by which perception effaces itself in favor of its products.

Source Quotes

The experience of chaos, on the speculative plane as much as on the other, leads us to see rationalism from an historical perspective that it claimed on principle to escape, to seek a philosophy that could render intelligible the springing forth of reason in a world that it did not create, and to prepare the living infrastructure without which reason and freedom are emptied or break down. We will no longer say that perception is a nascent science, but rather that classical science is a perception that has forgotten its origins and believes itself to be complete. The fundamental philosophical act would thus be to return to the lived world beneath the objective world (since in this lived world we will be able to understand the law as much as the limits of the objective world); it would be to give back to the thing its concrete physiognomy, to the organisms their proper manner of dealing with the world, and to subjectivity its historical inherence; it would be to rediscover phenomena (the layer of living experience through which other people and things are first given to us, the system “Self–Others–things” in its nascent state); it would be to awaken perception and to thwart the ruse by which perception allowed itself to be forgotten as a fact and as perception to the benefit of the object that it delivers to us and of the rational tradition that it establishes. [b.

We will no longer say that perception is a nascent science, but rather that classical science is a perception that has forgotten its origins and believes itself to be complete. The fundamental philosophical act would thus be to return to the lived world beneath the objective world (since in this lived world we will be able to understand the law as much as the limits of the objective world); it would be to give back to the thing its concrete physiognomy, to the organisms their proper manner of dealing with the world, and to subjectivity its historical inherence; it would be to rediscover phenomena (the layer of living experience through which other people and things are first given to us, the system “Self–Others–things” in its nascent state); it would be to awaken perception and to thwart the ruse by which perception allowed itself to be forgotten as a fact and as perception to the benefit of the object that it delivers to us and of the rational tradition that it establishes. [b. Phenomena and “facts of consciousness.”] This phenomenal field is not an “inner world,” the “phenomenon” is not a “state of consciousness” or a “mental fact,” and the experience of phenomena is not an introspection or a Bergsonian intuition.

Key Concepts

We will no longer say that perception is a nascent science, but rather that classical science is a perception that has forgotten its origins and believes itself to be complete.
The fundamental philosophical act would thus be to return to the lived world beneath the objective world (since in this lived world we will be able to understand the law as much as the limits of the objective world);
it would be to give back to the thing its concrete physiognomy, to the organisms their proper manner of dealing with the world, and to subjectivity its historical inherence;
it would be to rediscover phenomena (the layer of living experience through which other people and things are first given to us, the system “Self–Others–things” in its nascent state);
it would be to awaken perception and to thwart the ruse by which perception allowed itself to be forgotten as a fact and as perception to the benefit of the object that it delivers to us and of the rational tradition that it establishes.

Context

Culmination of subsection (a), where Merleau-Ponty articulates his positive phenomenological project as a 'return to the lived world' and a rediscovery of the phenomenal field of Self–Others–things.