Mary Aldis agitated for women's access to higher education, championing the campaign for female admission to Durham University and pushing for formal recognition through degrees, culminating in the groundbreaking Newcastle Memorial petition in 1880.

Her letters and articles in local newspapers ignited discussions on a wide range of issues, from gender equality and women's suffrage to education and workers' rights.

[3] Both Aldis and her husband were active in social reform efforts, commenting on matters relating to vaccination, vivisection, atrocities in Jamaica and the Congo, and women's access to higher education.

[5] She spoke publicly about the unfair treatment received by women students at Cambridge University, who were at that point only allowed to sit the Tripos by special permission, and could only gain a certificate in recognition of their success.

In 1880, together with her husband, Aldis circulated a petition (known as the Newcastle Memorial) urging the university to allow women students to be admitted by right and to earn formal degrees.

A review in the New Zealand press was positive, saying "The child, at the conclusion of these lessons, will have a better understanding of the meaning and intention of figures than if he had battered his poor little head against the hard rules of the approved school-books for a whole year.

Creese noted that unlike many other astronomical works at the time, Aldis did not set much store on Schiaparelli's channels on Mars that some claimed were evidence of life, but instead focused on spectroscopic analysis of the planet.

[12][13] Amy Aldis, in her short biography of her father, notes that her parents were disturbed by the openly licensed prostitution they observed in Auckland, and resolved to agitate against it, even if it cost him the professorship.

[14][5][4] Historian James Keating writes that Aldis was "a social purity campaigner whose postal activism inflamed a trans-imperial scandal concerning New Zealand’s Contagious Diseases Act".

[4] In January 1887, Aldis wrote to protest the council allowing a woman to be fired from a cannon (the mayor replied that they did not have powers to stop it, and the performance went ahead).

[18] Their pacifist views also led Aldis and her husband to speak out against the proposed military salute after the Duke of Clarence died in 1892, and to object to the rifle practice of the local Volunteers as a waste of money.

[19] In 1892, Aldis and her husband supported Katherine Browning, a teacher who completed the Tripos at Girton College and wanted to convert it to a Bachelor of Arts through the University of New Zealand, an option that was available to male students.

A. Froude met the Aldises several times, and described them as "of the elect of cultivated man and womankind", and Mary Aldis as "a lady as accomplished and gifted as [her husband]".

[5] Other contemporary responses to Aldis's campaigning acknowledged her support for votes for women, and that she was "deserving of commendation for dealing frankly and courageously with social questions affecting the welfare of her sex".

[26] It was considered worth noting in The New Zealand Herald that when Aldis signed the Suffrage Petition, she described her occupation as "writer", rather than the more common "domestic duties" or "gentlewoman".

[32] "The Critic", in Sydney described Aldis as "a blue-stocking, a violent, aggressive Wesleyan, a woman's rightist, and a strong anti everythingarian [sic].