Editing Franz Brentano (section)

===Theory of judgment===
{{More citations needed section|date=March 2010}}
Brentano has a theory of judgment which is different from what is currently the predominant ([[Gottlob Frege|Fregean]]) view. At the centre of Brentano's theory of judgment lies the idea that a judgment depends on having a [[Mental representation|presentation]], but this presentation does not have to be predicated. Even stronger: Brentano thought that [[Predicate (grammar)|predication]] is not even necessary for judgment, because there are judgments without a predicational content. Another fundamental aspect of his theory is that judgments are always [[Existential clause|existential]]. This so-called existential claim implies that when someone is judging that S is P he/she is judging that some S that is P exists. (Note that Brentano denied the idea that all judgments are of the form: S is P [and all other kinds of judgment which combine presentations]. Brentano argued that there are also judgments arising from a single presentation, e.g. “the planet Mars exists” has only one presentation.) In Brentano's own symbols, a judgment is always of the form: ‘+A’ (A exists) or ‘–A’ (A does not exist).

Combined with the third fundamental claim of Brentano, the idea that all judgments are either positive (judging that A exists) or negative (judging that A does not exist), we have a complete picture of Brentano's theory of judgment. So, imagine that you doubt whether midgets exist. At that point you have a presentation of midgets in your mind. When you judge that midgets do not exist, then you are judging that the presentation you have does not present something that exists. You do not have to utter that in words or otherwise predicate that judgment. The whole judgment takes place in the denial (or approval) of the existence of the presentation you have.

The problem of Brentano's theory of judgment is not the idea that all judgments are existential judgments (though it is sometimes a very complex enterprise to transform an ordinary judgment into an existential one), the real problem is that Brentano made no distinction between [[Object (philosophy)|object]] and presentation. A presentation exists as an object in your mind. So you cannot really judge that A does not exist, because if you do so you also judge that the presentation is not there (which is impossible, according to Brentano's idea that all judgments have the object which is judged as presentation). [[Kazimierz Twardowski]] acknowledged this problem and solved it by denying that the object is equal to the presentation. This is actually only a change within Brentano's theory of perception, but has a welcome consequence for the theory of judgment, viz. that you can have a presentation (which exists) but at the same time judge that the object does not exist.