 One way of thinking about what Conjunction Costs Probability says is that the stronger a statement is, the greater the risk of falsehood. If we strengthen \(A\) by adding \(B\) to it, the resulting, stronger statement is less probable. Unless, that is, there was no chance of \(A\) being true without \(B\) to begin with. In that case, adding \(B\) to \(A\) doesn’t change the risk of falsehood, because there was no chance of \(A\) being true without \(B\) anyway.