Ad hominem essentially allows an individual to critique from the inside out, making it easier to show the fallacies or contradictions in the other's argument.
"[4]: 496 Early in his career, Johnstone viewed rhetoric as simply a means of deceiving the audience into believing a certain assertion made by the orator.
[citation needed] He viewed philosophy in a more noble and truth-seeking light: "No philosopher worthy of the name would wish to secure assent to his position through techniques concealed from his audience.
[citation needed] Johnstone advanced and discussed the notion of rhetoric as "a wedge," in the sense that it serves as a tool to open a gap between the input of data and its acceptance.
"[7]: 76 Johnstone's discussion of rhetorical and dialectical argument was viewed as being highly original, and at odds with the prevailing logical empiricism of the time.
Many accredit him for adequately showing that ad hominem argumentation was quite typical surrounding philosophical writings, and had much broader use than previously thought.