I would say future thinking is about predictions (one particular outcome) or forecasting (several outcomes) as one develops a thorough argument. In this sense, argument does not mean "grandstanding" (slide 3) or a disagreement, but rather involves articulating a claim, counter claim, evidence, warrant, etc. to a particular audience. A prediction is a type of claim (one that expresses the future), and is just one facet of what makes an argument.
When we talk about education futures, we need to be making predictions based on sound arguments. This includes looking at trends, patterns, perspectives, contexts, etc. through an open and ongoing dialectic.