He then talks of things of which he can be certain, starting with ‘I am certain that I exist as a thinking thing’
12 One of the main criticisms of the Ontological Argument comes from Kant and his belief that existence is not a predicate. A predicate is the part of a sentence that gives information about the subject of a sentence. Kant argues that we cannot go round adding existence as a property of God, or anything else, in order to define God or anything else into existence. To say something exists does not add a description as a predicate does. It says that in the real world there exists a being that corresponds to the concept.
13 There is no model answer to this question. Whether you think Kant was successful or not you will be examined on your ability to justify your view. You could, for example, say that philosophers who agree with Anselm or Descartes are entitled to argue that God is a special case and then say why you think so or you could simply agree with Kant and explain what you see as the strengths of his arguments.