OK, so for the sake of this argument, we'll say that random elementary particles don't cause random behaviour at a macro scale. We'll say it's determinate.
See the problem?
If you mean for instance how the human brain works in this view, such as in decision making, then what I'm explaining is
neither 'determinate' in the sense of
fully predictable (as I was explaining above),
nor are the choices the brain would make fully indeterminate like 'dice rolling' in the sense of just random choices. Neither one.
Instead, a different
(3rd) picture is quite possible -- I was trying to explain that above.
Actually, weather forecasting is a useful analogy in one way. Currently it's all done in terms of probabilities, because we know that we cannot be sure it will rain, where and when, but only have a regional estimate, which might turn out entirely wrong in a dramatic decisive way in any given week, where an 80% chance of rain turned into zero rain across the forecast region, etc.
But weather is a useful analogy in this way: it's
reasonably predictable (to a useful extent, even with errors), but may continue to fall short of being fully predictable at some meaningful timescale (like 3 weeks or instance, or 4) if nature has true quantum randomness. With that truly random elementary particle behavior, there is some timescale where the forecast is just failing (not even getting it better than a coin toss at that time scale). In this picture, longer term weather forecasting might hit a wall in a frame (like 3, 4, 5 weeks?), where
no further increases in more extensive (fine grid, precise) observations (data for input) nor any further increase in of computing power (even as many orders of magnitude more computation as you wish)
would ever improve the reliability of that x week out forecast past some point in time x weeks (so that it will never get to 100% precise with 100% reliability), but it would always just be some lesser percentage in actual outcomes, where it might not rain on a given day in a given region where the computation said it was very likely, even "90%" (of course such numbers are rounded), etc. Note that here is only addressed merely one aspect regarding determinism (how it a system might be fundamentally neither deterministic nor truly random, but something else). Of course, there is far more to consciousness than merely whether it's deterministic or not (and in spite of many ideas about consciousness presented over time, it's still sorta like the question of how to interpret quantum mechanics: definitely not yet settled and there are many competing theories.