The Topics: Discovery of arguments, P. J. Corbett--Darwin, the Origin of Species

Analogy produces probable truth. Analogy argues that if two things are alike in one of two characteristics, they are probably alike in another characteristic. This argument is similar to Campbell's notion of Vera causa logic pg 363 which means in harmony with other causes already known. Vera causa treats things that are the same the same way. It does not work where there are distinctions.

For Aristotle, rhetoric concerned probable knowledge, which includes dialectic. In classifying, he was very much the scientist. But when he comes to the Topics, his social constructionism comes through.


The Topoi, Corbett makes a neo-Aristotelian stance, to result in a contemporary compilation of Aristotle's take presented randomly withing the context of an ongoing discussion.
Useful for seeing through a terministic screen the way scientists argue along with Latour, Toulmin, etc. Corbett's is a very "classical" take.
Bitzer's argument of exigence is mechanical rather than causal (side note).

Vera causa--Darwin uses causality based on observation

A versa causa argument, which means true cause, is a direct response to the .....To work, with vera causa, one has to establish the existence of a potentially causal process then demonstrate that the process is competent to explain the phenomenon of interest and that the process is inf act possible.

Darwin wanted to build the argument that would be acceptable to the audience first before making declarative statements.
Topoi in the Origin of the Species: the use of precedents..where accepted facts exist--law

Darwin's vera causa argument:
1. ability of new conditions to cause heredity variants in domestic species
2. the struggle for existence entails that just such a selective breeding exists
3. natural selection has longer to work and is more discriminating than artificial selection, so
4. the extant and extinct species could have originated as races produced by natural selection. Thus species probably did originate as varieties or races produced by natural selection.

Darwin's is a muted revolution in Biology

Darwin makes the case for the scientific method that of the hypothetico-deductive from which you deduce the truth. You use selective induction, find what you want to support the hypothesis--the myth of induction. Induction is based on analogy (Corbett, Campell)and analogy is the weakest form of argument. It is weak because it draws a probable conclusion from one form of similarity--if two things are similar, induction brings them together, classifies them, and then draws conclusion...it's circular reasoning, paralogical


Aristotle on Emotions

Rhetors need to understad the role of character and emotion in persuasion.
Aristotle's concern for rhetoric provided with the opportunity to develop a discussion on emotions. This is because judgment is the object of rhetoric and judgements vary with emotions.

Emotions are the things on account of which the ones altered differ with respect to
their judgments, and are accompanied by pleasure and pain: such are anger, pity,
fear, and all similar emotions and their contraries. (Rhetoric 1378a20-23)

Emotions are temporary states, says Aristotle, but they affect judgement. They are an example of external causality.
Logos-->Pathos-->Ethos-->

It's all about how to use emotions in rhetoric...emotions are multi-dimensional (Steve Katz).

Darwin on Emotions
According to Darwin, emotion generates emotion, which is manifested in three forms:

• certain expressions spring from habit
• certain expressions go to their natural opposite when the emotion is reversed
• emotions are a response of the nervous system

Begin by defintion