I have mentioned Lewis a number of times in these posts; his suggestion of the shared electron covalent bond still underpins much chemical thinking. Take for example mechanistic speculations on the course of a reaction, a very common indulgence in almost all articles reporting such, and largely based on informed arrow pushing. This process is bound to follow the rules of reasonable Lewis structures for any putative intermediates. Here, I suggest that we are now firmly in an era where such speculations must of necessity be backed up by quantum mechanical estimates of the energies and structures. I would propose that journals routinely encourage referees to insist on such (additional) checks. Let me give one specific example of the need to do this (part of a follow up to an earlier article I blogged on previously).