"combo" sentences

“Combo” Sentences

So far every argument we’ve looked at has had each premise stated as a separate sentence, and the conclusion likewise stated as a separate sentence. But English allows a more compact variation on this pattern, where an entire argument can be squashed together into one long sentence. Since every argument must be arguing for something – the conclusion – and must be trying to convince you of that conclusion, by given reasons for it – the premises – we know that such a long, single-sentence argument would have to contain at least two smaller sentences: a premise, and a conclusion. A squashed-together argument of that sort would be a combination of a premise and a conclusion, all glued together in one (longish) sentence. For this reason, I call such a single-sentence argument a “combination sentence” – or (for short) a “combo sentence”.

Here’s an example:

The light is off, so he's already gone to bed.

The first clue that this long sentence is a “combo” sentence is that it will contain a marker phrase – either a premise marker, or a conclusion marker. In this example, the word “so” appears in the middle of the sentence.

“So” is a conclusion marker, marking what follows it as a conclusion. That means the small sentence following “so” in this example is a conclusion.

The light is off, so [[he's already gone to bed] <-- conclusion]].

Now, since this little sentence is a conclusion, it is being inferred from some piece of evidence – from some premise or premises. Unlike a simple, non-argument statement, a conclusion is a sentence that’s concluded from some other sentence(s) – namely, the premise(s) in support of that conclusion.

In fact, the other little sentence here – “the light is off” – is clearly being presented as the reason why we should believe the conclusion (that he’s already gone to bed). The other little sentence is a premise in support of the conclusion.

[[The light is off] <-- premise], so [[he's already gone to bed] <-- conclusion]].

So this sentence presents us with a complete little argument. That’s the nature of every combo sentence: it will contain both a conclusion, and a premise in support of that conclusion; and it will mark one of these with a marker (either a premise marker, or a conclusion marker)

And remember: in our official, dissected form, each premise of the argument is listed on a separate line, and given its own number; then a line is added, separating the premise(s) from the conclusion; and the conclusion is listed last, with its special conclusion sign
(

). In official, dissected form, the little combo sentence argument would look like this:

1. The light is off. [line] [conclusion mark] He's already gone to bed.

What was originally one long (combo) sentence in English must be broken up into two separate sentences in official argument form. So combo sentences introduce a new complication for dissecting arguments, and putting them into official argument form: unlike a sentence which is only a premise, or only a conclusion, a combo sentence needs to be broken in two.

Here’s a second example of a combo sentence:

To identify which part is which in a combo sentence, we start by picking out the marker phrase. Every combo sentence will have at least one marker. In this example, the marker is “since”.

Now, “since” is a premise marker. So the little sentence immediately after “since” – “the square has a side two inches long” – is a premise.

Since [[the square has a side two inches long] <-- premise], it has an area of four square inches.

Of course, a premise (as opposed to a simple, non-argument-related declarative sentence) is a premise in support of some conclusion. The conclusion being drawn from this premise is the other little sentence, “it has an area of 4 square inches”.

Since [[the square has a side two inches long] <-- premise], [[it has an area of four square inches] <-- conclusion].

Here, again, a combo sentence provides a complete argument, glued together in one long English sentence. When putting this argument into official form, we need to break the combo sentence apart into two separate sentences.

1. The square has a side two inches long. [line] [conclusion sign] It [the square] has an area of four square inches.

One last observation: earlier combo sentence were described as having a premise and a conclusion stuck together in either order, to form one long sentence. While the two examples of combo sentences we’ve just looked at both had the premise first, combo sentences won’t always have their parts in that order. As an illustration of this, consider a minor variation on the last example:

Here we have the same two sentences, only in reversed order. But switching the order won’t by itself change the argument; for here again, we have the marker “since,” coming before the little sentence “it has a side two inches long”. As the word “since” is a premise marker, here again the little sentence “it has a side two inches long” is marked as a premise.

The square has an area of four square inches, [since] [[it has a side two inches long] <-- premise].

And here again, the other little sentence, “the square has an area of four square inches,” is presented as a conclusion that is supposed to follow from that premise.

[[The square has an area of four square inches] <-- conclusion], since [[it has a side two inches long] <-- premise].

So in this combo sentence, even though the order of the parts is reversed, the argument in official form will be the same as in the previous example.

1. [The square] has a side two inches long. [line] [conclusion sign] The square has an area of four square inches.

As we see, combo sentences aren’t in themselves especially complicated – they only introduce a bit of a complication, in breaking one long sentence into two separate, shorter ones. But as we will see next, when combo sentences show up as part of larger arguments, they reveal a more serious complication involved in dissecting arguments.

beakley > 1900 > informal logic

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