Greek has a lot of conjunctions, aka particles, aka little words that don’t change form and alter the meaning in often subtle and tricky ways. Even in the NT, which by comparison to Classical and more literary Koine is pretty particle-sparse, there are a lot of them and they cause difficulties.

Most grammars describe these words by listing a variety of English translation equivalents or describing various broad semantic categories and putting different particles in each box. This approach has some helpful aspects. First, when it come to translating texts or doing English-primary exegesis of Greek texts, it gives an easy English “equivalent” to use. It also rightly recognizes that English works differently than Greek and cautions the simplistic impulse of the learner that one word should have one meaning (by which most people mean “one translation”) that hangs around in all its uses. However, it has (at least) two major drawbacks. First, it gives the impression that the Greek particle “means” the same thing as the English translation “equivalent,” which is problematic. Second, this approach gives the impression that there is little to no difference between various particles. For example, consider the pair καί and δέ. In Daniel Wallace’s admirable Greek Grammar Beyond the Basics, each of these appear in the following semantic categories: ascensive, connective, contrastive, and correlative (though the distinction between them in this last category is pretty easy to make). Both can be translated as and or but.

So, what exactly is different about the two? Do they “mean” the same thing when they function in each of these categories?

Function of particles: signaling types of cohesion

One of the advances in Greek grammar in the recent past has been in describing the ways that the various particles function in terms of how they work in Greek without reference to how we translate them. From this understanding the reader and/or translator can consider how to best carry out that function in terms of English, or whatever other language they happen to be working with. The term function is important. Often a particle, like δέ, has no real semantic content and so describing what it “means” is not helpful. What is truly helpful is describing how it functions. Consider the following description of what particles do:

“[particles] indicate how certain parts of the text itself relate to each other, or how the text relates to the attitudes and expectations of the speaker and the addressee” (Cambridge Grammar of Classical Greek 59.2).

This approach to particles has advanced to the point that it is included in newer grammars, no longer requiring specialized works to find a discussion on it.

A tale of two particles

Let’s briefly consider the difference between the particles καί and δέ. Describing καί by itself is easier as it maps pretty well onto English and—rarely will this equivalence lead you astray. καί connects things said about a topic. It connects equal elements—whether single words, phrases, clauses, or whole large chunks of text—together in an addition-like fashion, which is a lot like English and. It is not the same, though, as and. The chief distinction is that καί does not mark semantic continuity, rather it just constrains the new material to be closely connected to the foregoing material. This is why sometimes elements joined by καί can be translated with an adversative but in English, even though and and but are semantic opposites in English and and is most like καί. Consider Rev. 3.1, where it makes great sense to translate καί with but:

  • οἶδά σου τὰ ἔργα ὅτι ὄνομα ἔχεις ὅτι ζῆς, καὶ νεκρὸς εἶ
  • I know your works that you have a name that you live, but you are actually dead.

The Greek here is not emphasizing the replacement of “alive” with “dead” at the level of syntax. That would be done with the particle ἀλλά. The particle καί tells the reader to add this next piece to the preceding piece, rather than to replace the previous statement as wrong (the main use of ἀλλά). In other words, both statements are presented as true: “you have the reputation that you are alive” and “you are (actually) dead.” While this leads quite easily into a contrastive reading because of the structure of the context, at the level of syntax contrast is not singled out. Greek is not English, so it makes sense that καί and and do not function entirely the same, however, the correspondence between them gives an easy point to hang a mental hat on.

δέ, by contrast, lacks a corelate in English, making it much harder grasp. Saying you can translate it as “but,” “and,” “now,” “then,” or often just leave untranslated is not very enlightening. Steven Runge defines the function of δέ as follows:

“The use of δέ represents the writer’s choice to explicitly signal that what follows is a new, distinct development in the story or argument, based on how the writer conceived of it.” Discourse Grammar of the Greek New Testament, 31.

This description is representative of the “new” way of describing δέ—it marks a development. In this way δέ is sort of the opposite of καί: καί marks continuation in an additive fashion and δέ marks development. Note that development is not contrast. The easy equation of καί with and and δέ with but is misleading as the two sets of particles have different relationships to each other in their respective languages. The key to coming to terms with this description of δέ is to figure out what development means, since it is not straightforward.

καί and δέ in action

Perhaps the best way to understand δέ is to grasp that it is not καί. καί continues a string, while δέ marks a degree of discontinuity, a non-continuation in the sense of καί. This “non-continuation” can take a variety of practical forms: a new section, a new sentence, a minor discontinuity, a replacement. Development does not even mean a new sentence; just a development in the way the writer is connecting ideas together. Let’s begin by considering one of Paul’s large sentences, Ephesians 4.20-24:

  • Ὑμεῖς δὲ οὐχ οὕτως ἐμάθετε τὸν Χριστόν, 21 εἴ γε αὐτὸν ἠκούσατε καὶ ἐν αὐτῷ ἐδιδάχθητε, καθώς ἐστιν ἀλήθεια ἐν τῷ Ἰησοῦ, 22 ἀποθέσθαι ὑμᾶς κατὰ τὴν προτέραν ἀναστροφὴν τὸν παλαιὸν ἄνθρωπον τὸν φθειρόμενον κατὰ τὰς ἐπιθυμίας τῆς ἀπάτης, 23 ἀνανεοῦσθαι δὲ τῷ πνεύματι τοῦ νοὸς ὑμῶν 24 καὶ ἐνδύσασθαι τὸν καινὸν ἄνθρωπον τὸν κατὰ θεὸν κτισθέντα ἐν δικαιοσύνῃ καὶ ὁσιότητι τῆς ἀληθείας.
  • But this is not the way you learned Christ, if indeed you heard (about) him and were taught in him—just as truth is in Jesus—that you put off the old man according to the former manner, which is being corrupted according to the deceitful desires, 23 and [δέ] (that you) be renewed in the spirit of your mind, 24 and [καί] (that you) put on the new man which is created according to God in righteousness and true holiness.

In these verses, there are three infinitive complements all hanging on the verb ἐδιδάχθητε “you were taught,” one at the beginning of each verse from 22-24. Of interest here is that in v. 23 we find the particle δέ, not καί (both translated “and” in English). This infinitive complement clause both continues on the internal development of this complex sentence and marks a discontinuity/development at the same time. From the Point of view of Paul, there is conceptual movement between v. 22 and v. 23—they are not joined together as though they are equal and additive. The infinitive complement clause stakes out a new development, a new direction in the argument, even as it continues on the same sentence. Contextually, there is a contrastive notion here, with the old v. new pattern at play (note, the contrast is due to the content of the context, not to the particle δέ, which does not inherently mark contrast). Verse 24, the third infinitive complement clause attached to ἐδιδάχθητε, by contrast, begins with καί. It does not mark out a development in the argument; rather, it continues the same line of thought begun in v. 23 by adding more content to it that is equal—one infinitive clauses added onto another one. In the passage, the difference in the “old” v. “new” makes a clear distinction between the two sub-sections unpacking “what you learned in him.” This development in the argument is marked out in Greek by the particle choice.

Development, then, does not mean moving on in a big way. It is a non-continuation, a non-καί. It tells the reader that the next unit is not simply an equal addition to the prior unit, but a moving on in some way. This “moving on” can be quite small, and can even happen within the boundaries of the same grammatical sentence as in the example above (just like καί), but it is a moving on nonetheless. (NB, the particle δέ functions at a clause/sentence level, while the particle καί can also function to connect individual words or phrases; thus, while in some sense they are sort of “opposites” in function, they have different distribution because καί can be used in more places).

Let’s look at one more example of the difference, this time from Titus 1.16:

  • θεὸν ὁμολογοῦσιν εἰδέναι, τοῖς δὲ ἔργοις ἀρνοῦνται, βδελυκτοὶ ὄντες καὶ ἀπειθεῖς καὶ πρὸς πᾶν ἔργον ἀγαθὸν ἀδόκιμοι.
  • They confess that they know God, and/but they deny him by their works, being profane and disobedient and unfit for any good work.

First, note that the two main clauses are connected by δέ. If the connection were made with καί here, the idea would be an extension, a continuation of the thought: they confess God and they deny him. Here the use of δέ puts things in a different light; rather than continuing the thought, it introduces a non-continuity, here a contrast (probably to be brought out by “but” in English). Rather than continuing on Point 1, δέ indicates that Paul moves on to Point 2. But, again, this is not a major break in the discourse or even a profound shift in topic. Development can be a rather subtle thing. The string of adjectives with the participle ὄντες are all connected by καί, marking them a group of connected and equal ideas.

Summary thoughts

These are just a few thoughts about how καί and δέ relate to one another and how to conceptualize the difference between them. Lots more could be said (and has been) about them. In truth, articulating what exactly δέ does is quite difficult, most obviously because of a lack of English correlate to even start with. The place to dig in is to see that δέ marks out a different type of connection than καί and keep filling out from there. I’ll leave this brief set of thoughts on this matter with a quote from the excellent (and short) treatment of the particles from the Cambridge Grammar of Classical Greek:

“Although both δέ and καί may be translated with and, these particles operate on different levels: whereas δέ serves to indicate shifts from one text segment/topic to another, καί connects several things said about a topic, linking several elements within a larger text segment.” (CGCG 59.21)