This sentence I think is slippery slope.

There is no value at all in Heidegger's philosophy, especially his ethics,since he collaborated with the Nazis in running German universities in the 1930s and fired all the Jews.

The sentence is just too long. How about this revision?

Heidegger's poor ethics prove that his philosophy is unfounded. He collaborated with the Nazis in running German universities in the 1930s, firing all the Jewish professors in the process.

I can't change the sentence I have to say it is either a phony refutation, direct way of refuting, reducing to the asburd, slippery slope, ridicle.

Check this site. I would change your sentence to say that Heidegger's support of Nazi politics has put his philosophy into question.

http://en.wikipedia.org/wiki/Martin_Heidegger#Criticism

Oh, sorry. I didn't understand the question.

Slippery slope states that "Event X has occurred (or will or might occur),
therefore event Y will inevitably happen."

It doesn't sound like that.

"Phony refutation: It’s not real refutation of an argument to point out that the person who made the argument has done or said something that shows he or she does not believe one of the premises or the conclusion of the argument."

Maybe it's phony refutation.

Diane, this site will be of help with fallacies.

http://www.nizkor.org/features/fallacies/

The sentence you provided seems to make use of a rhetorical device called a "slippery slope." This device is often used to suggest that one action will inevitably lead to a series of negative consequences or events. In this case, the sentence suggests that because Heidegger collaborated with the Nazis and fired all the Jews, his philosophy, particularly his ethics, has no value at all.

To address your statement, it is important to recognize that evaluating the value of a philosopher's work should be based on the merits of their ideas and arguments, rather than their personal actions or associations. While Heidegger's collaboration with the Nazis is a significant historical fact, it does not automatically invalidate his entire philosophical system or discredit his ideas.

To form an informed opinion about Heidegger's philosophy and ethics, it is necessary to engage with his writings, ideas, and arguments directly. Understandably, his collaboration with the Nazis may raise valid ethical concerns and criticisms, but it does not eliminate the potential value in analyzing and evaluating his philosophical concepts.

Considering different perspectives and engaging in critical analysis can help form a more nuanced understanding of Heidegger's work. It is important to separate the ethical judgment of an individual's actions from the evaluation of their philosophical contributions.