The anselmian Unum Argumentum has received a particular attention in the contemporary philosophical debate, and especially in analytic philosophy
In the first lesson, we will see the philosophical position of Alvina Plantinga, and his particular reconstruction of the proof. We will notice that Plantinga’s version of the argument is founded on the “Principle of Superiority of Existence” (PSE), which is also commonly used in all the reconstructions of the argument: according to him, this premise represents a controversial and problematic point, because of its thorny philosophical implications. So, although this Principle is a reasonable assumption, there is however the possibility to not accept it, refusing at the same time the validity of the entire argument too.
In the second lesson, we will see some of the main kantian critics against the proof, and the answers given to them by Plantinga. It will be explained why the kantian objections are not so conclusive and decisive as Kant thought: actually, they are based on some previous philosophical assumptions (opposite but equivalent to the PSE) concerning the concept of “existence”. These assumptions are very controversial and philosophically problematic: so, if they are accepted, then the kantian critics are acceptable too; but if they are rejected, then all the kantian objections decay completely.
In the third lesson, finally, it will be proposed a new interpretation of the anselmian argument (closer to the spirit and the letter of the text of the Proslogion). This new reading of the proof is radically different from the others, because it is founded on very simpler and more universally acceptable assumptions, which don’t touch the controversial points raised by the PSE and the kantian conception of “existence”. This new interpretation shows that the original Anselm’s argument is immune from the traditional kantian and Gaunilo’s objections, and it is stronger with respect to other versions of the proof.