... δῆλον γὰρ ὡς ὑμεῖς μὲν ταῦτα [τί ποτε βούλεσθε σημαίνειν ὁπόταν ὂν φθέγγησθε] πάλαι γιγνώσκετε, ἡμεῖς δὲ πρὸ τοῦ μὲν ᾠόμεθα, νῦν δ' ἠπορήκαμεν ...
'For manifestly you have long been aware of what you mean when you use the expression "being". We, however, who used to think we understood it, have now become perplexed.'i
Do we in our time have an answer to the question of what we really mean by the word 'being'?1 Not at all. So it is fitting that we should raise anew the question of the meaning2 of Being. But are we nowadays even perplexed at our inability to understand the expression 'Being'? Not at all. So first of all we must reawaken an understanding for the meaning of this question. Our aim in the following treatise is to work out the question of the meaning of Being and to do so concretely. Our provisional aim is the Interpretation3 of time as the possible horizon for any understanding whatsoever of Being.4
But the reasons for making this our aim, the investigations which such a purpose requires, and the path to its achievement, call for some introductory remarks.
1 'seiend'. Heidegger translates Plato's present participle ὄν by this present participle of the verb 'sein' ('to be'). We accordingly translate 'seiend' here and in a number of later passages by the present participle 'being'; where such a translation is inconvenient we shall resort to other constructions, usually subjoining the German word in brackets or in a footnote. The 'participle 'seiend' must be distinguished from the infinitive 'sein', which we shall usually translate either by the infinitive 'to be' or by the gerund 'being'. It must also be distinguished from the important substantive 'Sein' (always capitalized), which we shall translate as 'Being' (capitalized), and from the equally important substantive 'Seiendes', which is directly derived from 'seiend', and which we shall usually translate as 'entity' or 'entities'. (See our note 6, H. 3 below.)
2 'Sinn.' In view of the importance of the distinction between 'Sinn' and 'Bedeutung' in German writers as diverse as Dilthey, Husserl, Frege and Schlick, we shall translate 'Sinn' by 'meaning' or 'sense', depending on the context, and keep 'signification' and 'signify' for 'Bedeutung' and 'bedeuten'. (The verb 'mean' will occasionally be used to translate such verbs as 'besagen', 'sagen', 'heissen' and 'meinen', but the noun 'meaning' will be reserved for 'Sinn'.) On 'Sinn', see H. 151, 324; on 'Bedeutung', etc., see H. 87, and our note 3, p. 120 below.
3 Heidegger uses two words which might well be translated as 'interpretation': 'Auslegung' and 'Interpretation'. Though in many cases these may be regarded as synonyms, their connotations are not quite the same. 'Auslegung' seems to be used in a broad sense to cover any activity in which we interpret something 'as' something, whereas 'Interpretation' seems to apply to interpretations which are more theoretical or systematic, as in the exegesis of a text. See especially H. 148 ff. and 199 f. We shall preserve this distinction by writing 'interpretation' for 'Auslegung', but 'Interpretation' for Heidegger's 'Interpretation', following similar conventions for the verbs 'auslegen' and 'interpretieren'.
4 '... als des möglichen Horizontes eines jeden Seinsverständnisses überhaupt ...' Throughout this work the word 'horizon' is used with a connotation somewhat different from that to which the English-speaking reader is likely to be accustomed. We tend to think of a horizon as something which we may widen or extend or go beyond; Heidegger, however, seems to think of it rather as something which we can neither widen nor go beyond, but which provides the limits for certain intellectual activities performed 'within' it.
Sein und Zeit p. 1