Existence of a phase transition in spin glasses?

The real space block spin renormalisation method is applied to an Ising model spin glass with various symmetric distributions of nearest-neighbour interactions. For different blocks in two and three dimensions, the first-order cumulant approximation yields a phase transition with a critical exponent alpha <or approximately=-2. However, two and three block-spin cluster approximations do not yield a phase transition. The authors conclude that previous results obtained by them and by other authors on this level of approximation are inconclusive.