So how about a verb like tries as in the example below.
1. Taro tries to impress Hanako.
The verb works a bit like seems. However, it is clear that Taro is actually doing something here.
2. Taro seems to like Hanako.
As mentioned earlier, Taro is not the SEEMER here. He is just part of a situation.
In 1, the verb works a lot differently in some ways.
In a verb like try, the subject is active in a way that is different from the subject of seems. These facts are easy to explain if we can merge features like this. Otherwise, it is not really clear how you could explain these facts at all.
Anyway, check out the PowerPoint slides here.