You raise some good questions. Although humans discuss emotions a great deal, there doesn't seem to exist formal definitions for those concepts. Despite this,

You raise some good questions. Although humans discuss emotions a great deal, there doesn't seem to exist formal definitions for those concepts. Despite this, data can be collected that sidesteps this fact that can be useful: we can ask many people if they feel particular emotions and draw conclusions from that data. Still we must concede that a shared definition may not exist, which weakens these conclusions. In the case of consciousness, we could ask many people if they thought that someone/something else was conscious, but it's not clear what value that would have.