According to Lipinski's rule of five (Lipinski et al., 1997), which are widely established rules to evaluate the druglikeness of molecules, the logP score should be lower than 5. So an unbounded optimization of logP has little practical usability. Perhaps a better task would be to optimize for all 5 rules in Linpinski's rule of five which includes constraints involving the number of hydrogen bond donors/acceptors and molecular mass.