This proof, formulated by St. Thomas Aquinas (1225 – 1274), originates from the degrees discovered in things. There is discovered greater and lesser degrees of goodness, truth, nobility, and others – this is no ground-braking statement.
Aquinas argues, there exists something ‘truest’, which, in consequence, is the greatest ‘being’. He then argues, based on the metaphysics of Plato and Aristotle, that these superlatives – the things that are most true, beautiful, et cetera – are the greatest truths and therefore the greatest beings, as is stated in Metaphysics Book II.
Furthermore, that which is the greatest in its way, is, in another way, the cause of all things belonging to it. Therefore, there exists something that is the cause of the existence of all things and every perfection whatever. Aquinas calls this ‘God’.
Over 700 years later, there is little credibility left of Aquinas’ proof.
The most prevalent criticism of this argument considers that we do not have to believe in an object of a greater degree in order to believe in an object of a lesser degree. Richard Dawkins, the most (in)famous Atheist thinker of our time, argues that just because we come across a “smelly object”, does not require that we believe in a “preeminently peerless stinker”.
“Something does not necessarily prove something else, let alone something less or more.”
For instance, a fire does not necessitate another hotter fire, nor a cooler one. The hottest fire does not necessitate any other cooler fire (for it could be the only fire in existence and therefore both the hottest and coolest fire, or all fires in existence could have the same temperature). But above all else, if the hottest fire of all fires would indeed exist, it does not necessarily have to be the cause of all smaller fires.
See other: Arguments Concerning God
Knowledge Guild 
Excellent reasoning, but then I’ve come to expect that from you.
You flatter me.