Colin McGinn, Thomas Pogge, or John Searle perhaps? No way!
It is actually Elizabeth Anscombe. My proof will proceed in two steps. First, I will establish the “dirty” part. And second, I will demonstrate the “old man” part.
Lemma (1): “Dirty”
A reliable source tells us:
Once when the Manchester Guardian did a series on successful women professionals, they interviewed Elizabeth and asked her, ‘How do you manage a household with a husband and six children while carrying on your full-time career?’ Elizabeth answered, ‘You just have to realize that dirt doesn’t matter.’ (J. Searle, “Oxford Philosophy in the 1950s”, Philosophy, April 2015)
Maybe this was Anscombe’s joke? Apparently not, because there is a witness who directly observed the dirt:
When I was tutored by Anscombe’s husband, Peter Geach, I went weekly to their house at 27 St. John’s Street. The first week I noticed there was a half empty cup of coffee sitting in the middle of the living room rug. As the weeks passed that cup of coffee grew first a cover of detritus which then gradually turned into a mold that developed during the term and was still growing in my last week.
So, “dirty”, yes.
Lemma (2): “Old man”
Wittgenstein notoriously didn’t tolerate women in philosophy but he made an exception for Anscombe, whom he (affectionately) called “old man”. Therefore, given that Wittgenstein was a genius and that he knew Anscombe very well it is undeniable that the description “old man” does apply to her.
So, “old man”, yes too.
Therefore, combining Lemma 1 and Lemma 2 we get:
CONCLUSION: Anscombe = dirty + old man = dirty old man.