Harry Potter:
I don't imagine an existence of a 'real' past or a 'real' future. The future will be actual when it comes; until then it is an abstract idea, not an actuality. So it is odd to suggest that desire is caused by imagining a possibility of future (that is actual when it comes). By your argument, if I "plan" my travel, then I automatically "desire" travelling. My investigations so far suggest that romantic desire has got nothing to do with notions of time, but all to do with the need to love and be loved waiting beneath the psyche wreaking havoc on pertinent perceptions (sight of a voluptuous body, for instance).
Harry, I don't think Adam is making an "argument" about time and desire. It sounds like he is reporting his experience. This isn't intellectual stuff :-)
Harry Potter:
By your argument, if I "plan" my travel, then I automatically "desire" travelling.
What it seems to me Adam is pointing to is that the experience of desire depends on believing a certain assumption about time, a certain way of experiencing "time" (as a succession of "moments" moving from past to future). To "want" depends on "lack" and to "lack" makes possible "getting". I "lack" it "now", will "get" it "then" (hope, optimism, self-esteem), or perhaps I will never "get" "it" (fear, dejection, pessimism, worthlessness). By operating according to this structure, we just reinforce the brain circuits that assume lack, and assume a temporal process of getting (or never getting) what we lack (in the ever-receding future). Thus we never question the actuality of "lack", or discover the illusory nature of desire/fear (and the kind of time which desire/fear assumes).
Again, the point being made is not intellectual, or else simply changing one's opinion about time, entertaining the opinion that only the "present" is actual, would be sufficient to dissolve desire and aversion. The "belief" in time is not intellectual, it occurs much much earlier in the cognitive/affective process of experiencing. It is there in the earliest developmental structures.
In some sense it seems to be the heart of the thing. These are experiential pointers, not intellectual pointers. No point in considering this very far on an abstract level. It's all about experiencing completely here and now, whether experiencing the obstructions to complete release (our "issues" or stories of why we can't be happy) or experiencing without obstructions (life as such, sans distortion). Intellectual reflection and investigation are only helpful insofar as they actually point one towards complete experience here and now. That's why I think a modest meditation practice can be helpful here, undertaken wisely, and Adam's advice about dropping notions of progress and attainment is appropriate in this latter context as well.