in terms of what it is concerned with. When this is endangered, Being-alongside is threatened. Fear discloses Dasein predominantly in a privative way. It bewilders us and makes us 'lose our heads'. Fear closes off our endangered Being-in, and yet at the same time lets us see it, so that when the fear has subsided, Dasein must first find its way about again.
Whether privatively or positively, fearing about something, as being-afraid in the face of something, always discloses equiprimordially entities within-the-world and Being-in—the former as threatening and the latter as threatened. Fear is a mode of state-of-mind.
One can also fear about Others, and we then speak of "fearing for" them [Fürchten für sie]. This fearing for the Other does not take away his fear. Such a possibility has been ruled out already, because the Other, for whom we fear, need not fear at all on his part. It is precisely when the Other is not afraid and charges recklessly at what is threatening him that we fear most for him. Fearing-for is a way of having a co-state-of-mind  with Others, but not necessarily a being-afraid-with or even a fearing-with-one-another.1 One can "fear about" without "being-afraid". Yet when viewed more strictly, fearing-about is "being-afraid-for-oneself".2 Here what one "is apprehensive about" is one's Being-with with the Other, who might be torn away from one.3 That which is fearsome is not aimed directly at him who fears with someone else. Fearing-about knows that in a certain way it is unaffected, and yet it is co-affected in so far as the Dasein-with for which it fears is affected. Fearing-about is therefore not a weaker form of being-afraid. Here the issue is one of existential modes, not of degrees of 'feeling-tones'. Fearing-about does not lose its specific genuiness even if it is not 'really' afraid.
There can be variations in the constitutive items of the full phenomenon of fear. Accordingly, different possibilities of Being emerge in fearing. Bringing-close close by, belongs to the structure of the threatening as encounterable. If something threatening breaks in suddenly upon concernful Being-in-the-world (something threatening in its 'not right away, but any moment'), fear becomes alarm [Erschrecken]. So, in what is threatening we must distinguish between the closest way in which it brings itself close, and the manner in which this bringing-close gets encountered—its suddenness. That in the face of which we are alarmed is proximally something well known and familiar. But if, on the other hand,
1 'Fürchten für ... ist eine Weise der Mitbefindlichkeit mit den Anderen, aber nicht notwendig ein Sich-mitfürchten oder gar ein Miteinanderfürchten.'
2 'ein Sichfürchten'. We have hitherto translated 'sich fl.irchten' with various forms of 'be afraid' which is its usual signification in ordinary German. In this passage, however, the emphasis on the reflexive pronoun 'sich' clearly calls for 'being-afraid-for-oneself'.
3 "Befürchtet" ist dabei das Mitsein mit dem Anderen, der ein em entrissen werden konnte.'