On a Friday in September, American markets found an unlikely kind of relief — not in good news, but in the end of uncertainty. Inflation arrived close to what had been feared, oil retreated from its heights, and the Federal Reserve's intentions came into sharper focus, allowing the Dow to shed a four-day losing streak and the S&P 500 to close higher. There is an old truth in markets, as in life, that a difficult path clearly seen is often less frightening than an easy one shrouded in fog.