"In dealing with the scope of the taxing power, the question has sometimes been framed in terms of whether something can be taxed as income under the Sixteenth Amendment. This is an inaccurate formulation of the question and has led to much loose thinking on the subject. The source of the taxing power is not the Sixteenth Amendment; it is Article I, section 8 of the Constitution. It is important that these provisions be clearly understood; what is required is an understanding of fundamental principles. The familiar statement that at this time we need education in the obvious more than investigation into the obscure (Holmes, Collective Legal Papers, pp. 292-293), although made in a different context, is peculiarly applicable here." Penn Mutual Indemnity Co. v. Commissioner of Internal Revenue, 32 T.C. 653 at 5659 (1959)