Looks pretty clear to me. > Congress shall have the Power to promote the Progress of Science and useful Arts, The goal or motive. > by securing for limited T

Looks pretty clear to me. > Congress shall have the Power to promote the Progress of Science and useful Arts, The goal or motive. > by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries. The means by which the goal is achieved. The benefit to authors and inventors are a means to and end, don't confuse the means for the motive.