The best way I've heard 2nd causes described is the example of the hammer driving the nail. Is the person using the hammer driving the nail, or is the hammer driving the nail? the answer is, of course, yes! the hammer cannot drive the nail without the person using the hammer causing it to move, yet it is the hammer that is driving the nail also, in making direct contact with it. the person using the hammer could have easily chosen another hammer to get the job done, but in that particular case it is that particular hammer that is used. I hope that makes as much sense to you guys as it did me when I first heard it!
troy

Grace is but glory begun;
Glory is but grace perfected!
- Jonathan Edwards