The standard (Keynesian) view of the Phillips Curve is that a strong economy leads to higher inflation. If I'm not mistaken, Milton Friedman reversed the causation, arguing that higher than expected inflation led to a stronger economy:
There is always a temporary trade-off between inflation and unemployment; there is no permanent trade-off. The temporary trade-off comes not from inflation per se, but from unanticipated inflation, which generally means, from a rising rate of inflation. The widespread
belief that there is a permanent trade-off is a sophisticated version of the confusion between 'high' and 'rising' that