There is a mode of philosophising which has it that what we need to do is get right our description of the fundamental character of world, mind and life. Of the world, of our mindedness, of our embodiment, of our relatedness to one another, etc. These matters are described wrongly by Cartesians, cognitivists, reductive materialists, etc. Our job is instead to describe them correctly. The lived body, intercorporeality, being-in-the-world, pre-reflective intentionality, etc. are the designations which collect together what we could call a positive phenomenological understanding of the nature of our life and world.
Now, being of a Wittgensteinian-therapeutic disposition I'm not one for the metaphysics, and so whilst I applaud the existential phenomenologists' repudiation of mentalism, materialism, dualism, introspectionism, etc., I see their invocation of a positive alternative as at best empty yet prophylactic and at worst as a wrong-headed endorsement of a conception of philosophy as a cognitive discipline. According to the perspective I prefer, mechanistic and mentalistic and materialistic pictures don't need replacing with better pictures sketched for us by Messrs Merleau-Ponty et al. Rather we need to understand that the pictures the existential phenomenologists diagnosed as suspect were nonsensical answers to a nonsensical question. And since the questions are themselves nonsensical we don't now need better pictures to replace the suspect ones. We rather need to stop trying to assimilate some aspects of our life and language to other bits of it - we need to resist the urge to generality.
So yes, if someone tries to offer us a philosophical anthropology that sunders essential internal relations between mind, body, world, others, etc. we do right to stress that the being of the human being is being-in-the-world, is intercorporeality, etc. But does this amount to more than either a) calling the metaphysician out on their claptrap? or b) describing not the human being itself but instead the grammar of our key terms like person, thought, perception, etc.? It seems to me that when earlier Heidegger attempts description of existence itself, the appearance of cognitive content in the philosophical claims starts to evaporate and we are left with only empty, platitudinous if poetic reminders to not be conceptual numpties. For the opposite of a piece of nonsense, I suggest, is not a description of the world but simply a rule of grammar.
Take any core concept: intentionality, human being, action, perception. Isn't it the case that our understanding of these concepts itself bottoms out in our practical grasp of these phenomena? Isn't it the case that any of the terms we are apt to marshall in our descriptive phenomenology are themselves only intelligible to us because of our prior practical competency in shunting these terms about, here and there, in the midst of our living?
For example, we are considering the nature of objects, and you offer as part of your putative descriptive phenomenology that objects have extension. I ask you what that means and you tell me about length and breadth and height. But you've drawn a short straw with me; somehow I never learned those concepts before. So you go to the tool box and get out a measuring tape, and hold it up against objects in the different dimensions. Or you just run your finger along the edges of the table this way and that. And now I come to understand, I get what you are on about, now I come to know how to use the word 'extension'. But surely it is now clear that it wouldn't be apt to say that I can offer a fundamental description of the nature of reality with the phrase 'objects have extension'. My 'theory' is, as it were, too laden by the 'data' for it to even get that distance from them required for mere describing.
This is why proper names are only designators and not descriptors. The name is given its sense by its tie to the thing, and so it can't be pretended that knowing the name's meaning gives us a grip on the being of the thing. It's most stark when we have to do with concept-determining samples. You give a meaning to 'X' through ostensive definition. Later on you tell me that ''it is a fact that X' forms part of a true description of the world'. And I tell you to get your head out of your conceptual backside.
What is a description? Well, if you want to describe something, you must already have some way of identifying it. Having identified it you can say of it that it is green and hairy. This has cognitive content, and that it does so is a function of the negations it entails: that it is not blue and smooth. What it is to say something about something is in part to not also say something else about it. It is to make a discrimination amongst possibles.
Philosophical phenomenology, however, does not offer us a discrimination amongst possibles. It offers us, I'd say, a rule masquerading as a description versus some impossibles. One of the tricks which keeps us from noticing this is the way in which it posits a super-object as that which is being partly described through the terms like 'coloured', 'has extension'. This super-object is 'the world' or 'reality'. (For some reason that I can't fathom, even many Wittgensteinians are attracted to 'the world'.) They don't seem to mean 'the planet' or anything I can actually get a discriminating handle on. No, they mean, like, everything!
In fact the only way I can get any kind of handle on how 'the world' is supposed to feature as the object of our alleged fundamental descriptions is if I bring in something somehow outside of it. Perhaps 'the mind' will do. But it's kind of the point of the phenomenological enterprise that we're not really supposed to do ontology like that (hence not minds, but Dasein...). So we're supposed to be describing still, but now abrogating another condition on description: that it is of this as opposed to of that.
The world as totality cannot be described; this is a grammatical proposition about 'the world'. Most of what I have written above is, however, a note on the grammar of 'description'.