In the cultural object, I feel the close presence of others beneath a veil of anonymity. Someone uses the pipe for smoking, the spoon for eating, the bell for summon-ing, and it is through the perception of a human act and another person that the perception of a cultural world could be verified. (405)
Merleau-Ponty On Our Primordial Encounter With Otherness
For Merleau-Ponty, any encounter with an Other is preceded by a pre-cognitive, pre-linguistic encounter with otherness in the form of anonymous others whom we encounter as a part of an objectively shared word. No longer there simply for me, the world and the things found therein immediately point us to others. When these others appear, our objectively apprehended world gets sucked into their sphere of influence, and we loose our position at the center of the world. As Merleau-Ponty describes:
Round about the [Other’s] perceived body a vortex forms, towards which my world is drawn and, so to speak, sucked in: to this extent, it is no longer merely mine, and no longer merely present, it is present to x, to that other manifestation of behaviour which begins to take shape in it. Already the other body has ceased to be a mere fragment of the world, and become the theatre of a certain process of elaboration, and, as it were, a certain ‘view’ of the world. There is taking place over there a certain manipulation of things hitherto my property. Someone is making use of my familiar objects. But who can it be? (411–12)
The mere existence of an Other takes us outside of our bodies and ourselves. The Other is a theater for the elaboration of a drama not of our own making. As we are drawn into their world of concern, we forget ourselves and our concerns. We come to be out there in the world, and as Merleau-Ponty suggests, the world comes to inhabit us. The other doesn’t just present us with the data of other consciousnesses, but the other affects us and acts upon us, as if love stricken.
The Lived Body and the Other
The Other is first of all perceived as a body, but this body is no mere object. The lived body of subjects is characterized by the reversibility of being both object and subject simultaneously. (For example, think of how you can simultaneously grasp your own hand, and be both grasping and grasped.) A special kind of object, the lived body of the other exhibits behaviors much like our own. More specifically, it can leave marks and traces as vestiges, and produces the space in which it moves by shaping its environment. In a somewhat cryptic but very suggestive passage, Merleau-Ponty writes:
The very first of all cultural objects, and the one by which all the rest exist, is the body of the other person as the vehicle of a form of behaviour. Whether it be a question of vestiges or the body of another person, we need to know how an object in space can become the eloquent relic of an existence; how, conversely, an intention, a thought or a project can detach themselves from the personal subject and become visible out- side him in the shape of his body, and in the environment which he builds for himself.” (406)
As a cultural artifact, the body of the Other can be interpreted or read for its significance. The simplest way to understand this is to take the example of the athlete or the dancer, off of whose bodies we can read the athleticism and poise produced through the way they use their bodies. Their bodies are an expression of their life’s work. Or we may read the calloused worker’s hands to mean that they world work with their hands. Even the lack of marks and traces says something about the other….
Furthermore, bodily attitudes communicate something about our psychological state — for example, if we are feeling defeated, we slump in our frames; when we are excited, our bodies exude with energy. If we are pricked, our facial expression and bodily wincing can communicate that sharp, sudden experience of pain. So bodies, like inert objects, can be “read” for the significance that they communicate against a cultural backdrop. In fact, our bodies may communicate and know what we have not (or cannot) consciously register, even against our wishes.
Finally, Merleau-Ponty here suggests that the environment in which we find ourselves and others is produced, in part, through the Other’s activities in and through that space. We are not just sucked into a psychological vortex when we encounter others, but the vortex may well be physical, around a whirl of activity not our own. It is as if our bodies are pencils that leave marks and traces, and that shape the space we inhabit.
How Our Encounter With Primordial Otherness Structures Our Subjectivities
Prior to conscious thought, prior to an exchange with a particular Other, the human world is there for us. There is no human world that does not always already include others, and it would be very difficult to imagine a meaningful world devoid of others. This is where Merleau-ponty makes his biggest move: primordial otherness structures my subjectivity because the Other comes across as completing a system. Merleau-Ponty re-narrates the encounter with otherness as follows:
I say that it is another, a second self, and this I know in the first place because this living body has the same structure as mine. I experience my own body as the power of adopting certain forms of behaviour and a certain world, and I am given to myself merely as a certain hold upon the world; now, it is precisely my body which perceives the body of another, and discovers in that other body a miraculous prolongation of my own intentions, a familiar way of deal- ing with the world. Henceforth, as the parts of my body together compromise a system, so my body and the other’s are one whole, two sides of one and the same phenomenon, and the anonymous existence of which my body is the ever-renewed trace henceforth inhabits both bodies simultaneously. (411–12)
Much like I recognize that all the parts of my body arranged in working order make up the unity I call my body, the hereto anonymous Other forms a part of the unity of the world in which I find myself, and is in fact a necessary condition for my coming to consciousness as a subject.
In this way, Merleau-Ponty gets back behind Husserl’s lifeworld  to suggest a prior encounter with otherness as a condition for the possibility for subjectivity. We are not first of all distinct from this world and others, but form a unity with them from which we later come to separate out our own individual subjective sense of self. Any encounter with a specific Other has as its backdrop a primordial encounter with, or connection to otherness.
Merleau-Ponty puts it most clearly in the following quote:
Between my consciousness and my body as I experience it, between this phenomenal body of mine and that of another as I see it from the outside, there exists an internal relation which causes the other to appear as the completion of the system. The other can be evident to me because I am not transparent for myself, and because my subjectivity draws its body in its wake.(410)
And later he will add this:
In reality, the other is not shut up inside my perspective of the world, because this perspective itself has no definite limits, because it slips spontaneously into the other’s, and because both are brought together in the one single world in which we all participate as anonymous subjects of perception.(411)
The word “imbricated” is often used to describe this situation, and this phenomenological description is meant to give a new starting point from which to overcome the problem of solipsism — of a subject that is shut up in itself. The reality of the solipsistic subject’s world is in question precisely because it cannot be verified. (Husserl preserves the subject/object inside/outside division intact in his account, a strategic solipsim he adopts in over to overcome it, but arguably his transcendental subject is never able to fully overcome the split. ) Merleau-Ponty attempts to overcome the mind/body subject/object split by denying it outright, arguing that the body/self is simultaneously subject and object, and that “the world is wholly inside and I am wholly outside of myself.” (474)
 You can find a good blog post on Husserl's theory of the Lifeworld and his theory of intersubjectivity here.
Quotes Source: Merleau-Ponty, Maurice. Phenomenology of Perception (New York: Routledge) 2005.