You keep saying that, and it's true that a bad implementation doesn't imply a bad principle. But a bad implementation doesn't rule out a bad principle either, so your statement above doesn't shed much light. There was plenty of scientific and social advancement before patents existed. Without patents, the barriers to "advancement of the arts and sciences" are lower, and people engage in a constant process of incremental improvement. With patents, you get pockets of more intense (but isolated) development, and a reduction in the number of scientists/engineers together with an increase in the number of lawyers. Regards, Roger