Taleb also discusses a more general issue, which is that of the usefulness of scientific improvements. His point is that VAR is useless because it is not perfect (unlike measures in the physical sciences). Admittedly, VAR is not perfect. Our world, however, is constructed by engineers, not physicists. And engineering has been described as the "art of the approximation." The same definition applies to VAR. In fact, risk managers are less concerned about precision than the traders who have to price derivatives. The advent of derivatives has been compared to allowing us to drive at a faster speed in financial markets. VAR is like a wobbly speedometer. Even so, it gives a rough indication of speed. Derivatives disasters have occurred because drivers or passengers did not worry at all about their speed. Of course, there can be other sources of crashes (such as blown tires, for instance). Such accidents can be compared to operational risks, against which VAR provides no direct protection. Still, a wobbly speedometer is better than nothing.