Signposts

About this video

People rarely label the parts of an argument, but they often leave little words that work like signposts on a road. Logicians call them indicators. Some come just before a conclusion: so, therefore, that's why, which means. Others come just before a reason: because, since, as, after all.

This short animation takes one sentence, "We should leave now, because the film starts at eight." The conclusion comes first here, and "because" points to the reason after it. Drawn as an argument map, the reason goes at the top with an arrow down to the conclusion. Said the other way round, "The film starts at eight, so we should leave now", it is the same argument and the same map: only the signpost changed.

Sometimes there are no signposts at all: "Don't touch that pan. It has just come off the stove." Then ask what the speaker wants you to believe or do, and try putting "because" between the two parts. If it still makes sense, you have found the conclusion. One warning from the lesson: "so" can also just mean "very", as in "I was so tired". This video goes with the Spotting the Conclusion lesson of Logic Level 1 on Knaph.

Transcript

1. 0:00Which part is the conclusion?
2. 0:04We should leave now, because the film starts at eight. Because points to a reason.
3. 0:12Say it with so, and it's the same argument, the same map.
4. 0:17So, therefore, that's why come before a conclusion. Because, since, after all, before a reason.
5. 0:23No signposts? Put because between the parts. Still makes sense? Found it.
6. 0:28So points to a conclusion. Because, to a reason.