Conjunctions vs the cooperative principle. This post is about using conjunctions in written English. Look at these two pairs of sentences: 1. The weather is great today. I like cats. 2. The weather is great today. I'm going out. I'm sure you can see the difference. In the first pair the two sentences have no connection. They're two separate ideas. In the second pair there is a connection. One leads to the other. The speaker is going our because the weather is great. To make this connection clear we could use a conjunction, or linking word. Both 'because' and 'so' could be used: The weather is great today, so I'm going out. I'm going out today because the weather is great. Why did I leave the conjunction out? It wasn't needed. When people are listening to you they are working with you to understand what you are saying. They are making connections and using their knowledge of you and their environment to make sense of your words. Another example of cooperation, this time in spoken English: Jim: The beach looks good. Dan: Okay let's go. I'll get my towel. Jim didn't say he wanted to go to the beach but Dan worked with him to understand he was suggesting it. Back to writing with conjunctions. Why not just use one to be sure you are clear? Here are two good reasons: Sentences will become far too long sometimes. Example: That cat comes to our house everyday and eats our food, plays with the dog, sleeps on our sofa, and walks around in our garden, SO I think at this point we can say that the cat is our pet AND we should give it a name, take it to the vet to check for disease, and buy it a collar. The SO and AND in that sentence could be taken out to make 3 shorter sentences. These will be easier to read and not lose any meaning. This post has reached it's size limit. If you're interested in reason two and more on conjunctions give it an upvote or leave a comment. Thanks.