This picture, whilst hilarious, looks at a somewhat darker side of critical thinking and rationality. Reductionist thinking tells us that there are only two options to this problem, either the glass is either half empty or half full, the problem puts us into camps of either being an optimist or a pessimist, which is an unjust judgement, considering the depth of human experience, can we really expect to be a ‘half full person‘ or the opposite? The reality, if we apply critical thinking is that the glass always full that is that regardless of whether there is liquid in the glass, there will always be some percentage of air (or other combination of gases). Overanalysing the problem? Maybe. But this problem does help to see how reductionist thinking is damaging, in that it completely disregards other options.
Being a ‘realist’ or a critical thinker is confronting, it makes you realise that there are terrors in the world that we cannot avoid (the big one being suffering and death), but when you are a real critical thinker, this is OK. Humans, like all other animals, are subject to the laws of nature and we will all die someday, so do we fill ourselves with false hope and avoid difficult conversations, or do we stay mired in telling ourselves half truths that merely falsely ease the way?
Skeptic's Guide to Life 