It’s an interesting idea.

Lies cannot exist without the truth.

The person telling a lie does so in reference to what he perceives as the truth. In so far, there is respect for the truth.

Bullshit doesn’t care about either lies or truth. It has no respect for the truth.

Bullshit is having something to say and wanting to be able to get away with it.

Now, one could ask how opinions and beliefs differ from bullshit as it doesn’t seem possible to objectify them as truths. However, there is an important relationship with truth, and it is that they are ours. It’s a belief that one has held and possibly changed along the way. It’s an opinion one has developed by integrating new ideas and learnings. We are true to them. They are true to us.

Bullshit has none of that.