Say that a function is a group of personality traits is wrong. Functions can only be described through traits, but not personality traits. They are descriptions of the sections of our personality. As I have said before, everyone values every function. This means that everyone is complete personality wise. For example:
Ti is what one uses when they look at the information to make judgments. As I have said before, all judgments are based on logical information. Ti is what we make the logical judgments based on. Ti people because of this are rational people. Ti has two sides. +Ti which is implicative logic. Implicative means common sense. This logic is about making inductions, or making decisions or judgments based off as little analysis as possible. -Ti is about analytical logic. Making decisions based off as much analysis as possible. Ti is the calculation of facts(+Te) and opinions(-Te). Ti is also the calculation to facts and opinions.
-Ti/+Te is about proof. Everything for this function has to be proven. -Ti analyzes the information and creates proof.
Fi is the actual judgment of things. Fi takes the logical information that the rational Ti has made and forms a decision. If I were to say that I like cookies, one would be using both Fi and Ti for this. That actual judgment is Fi. To believe that I actually like cookies is a subjective ideology(as the IM definitions state that Fi is). So why do we like the cookies? There is a sweet substance(Te and Fi) in the cookie. This is an example of Ti usage. Ti and Te created the logic bridge to Fi. This is an example of judging functionality. Thinking functions are the logical information and Feeling functions are the subjective evaluation.