The planned destruction of the families, languages, cultures and traditions of the Indigenous communities of Canada through the residential school system was "genocide," Pope Francis said.

Asked by an Indigenous reporter why he did not use the word genocide while in Canada, the pope said, "I didn't use the word because it did not come to mind, but what I described was genocide."

"And I condemned it," he said, during his inflight news conference July 29 at the end of a trip that had begun July 24.

Another Canadian reporter asked Pope Francis about the "Doctrine of Discovery," a collection of papal teachings, beginning in the 14th century, that blessed the efforts of explorers to colonize and claim the lands of any people who were not Christian, placing both the land and the people under the sovereignty of European Christian rulers.

Pope Francis said it always has been a temptation for colonizers to think they were superior to the people whose land they were colonizing. In fact, he said, there even was "a theologian, who was a bit crazy," who questioned whether the Indigenous of the Americas had souls.

"This is the problem of every colonialism, even today," he said, pointing to modern forms of "ideological colonialism," which use requests for foreign assistance to force poorer countries to adopt policies that go against the values their people hold dear.

"This doctrine of colonialism truly is evil, it's unjust," the pope said.

Because of continuing knee pain, the pope did not stand in front of the journalists' section for the 40-minute news conference, but rather sat in portable chair in the aisle.

"This trip was a bit of a test" to see how much he could handle and how much of what was considered a standard part of a papal trip was really necessary, he said. "Perhaps we will have to change the style a bit, reduce a bit."

But the pope said he still hopes to visit Kyiv, Ukraine -- "we'll see what's possible" -- as well as go to Kazakhstan in September for an interreligious meeting.

He also said he wants to reschedule his ecumenical trip to South Sudan with Anglican Archbishop Justin Welby of Canterbury and the Rev. Iain Greenshields, moderator of the Church of Scotland. They were supposed to go in early July, but the pope was forced to cancel to give his knee treatments more time to work.

"I have all the good will" to keep traveling, the pope said, "but we'll have to see what the leg says."

As for retiring, Pope Francis told reporters: "The door is open. It is one of the normal options, but up to now I haven't knocked on that door."

"I haven't felt like I needed to consider this possibility," he insisted, "but that doesn't mean that the day after tomorrow I won't start thinking about it."

"Stepping aside," the pope said, would not be "a catastrophe. You can change popes, no problem."

He insisted again that he would not have surgery on his knee because, he said, he reacted badly to anesthesia in July 2021 when he had colon surgery.

"But I will try to continue to make trips and to be close to the people, because I think it is a way to serve," he said.

Pope Francis also was asked about an unsigned "declaration of the Holy See" regarding the German church's Synodal Path that was published July 21.

The declaration warned that if the Catholic Church in Germany tried to "initiate new official structures or doctrines in the dioceses prior to an agreed understanding at the level of the universal church," it would be "a wound to ecclesial communion and a threat to the unity of the church."

"That communique was written by the Secretariat of State," Pope Francis said. "It was a mistake not to say so," but it was an oversight and "not out of bad will."

Pope Francis said he had spent a month praying, reading and consulting with a variety of people before he wrote a letter to German Catholics in 2019 urging them to ensure their Synod Path was a process of prayer and discernment and not simply a search for an efficient way to handle challenges facing the church in Germany.

"I wrote it as a pastor to a church that is trying to find its path forward," he said.

After reports that Pope John Paul I, who will be beatified in early September, had supported changing church teaching on artificial contraception in some cases and after the publication of a book of papers from a Vatican-related conference where theologians debated that issue and others, Pope Francis was asked what he thought about the possibility of "developments" in church teaching on contraception.

In his response, Pope Francis did not talk about the church's teaching against the use of artificial contraception. Instead, he spoke of the role of theologians in the church and about the development of doctrine.

Church teaching "is always in a state of development," either through being confirmed and consolidated over time or by being understood more precisely in relation to new problems or deeper understanding, he said.

The job of theologians, the pope said, is to explore the possibilities, while the job of the pope is to "help them understand the limits."

As an example of how church teaching develops, Pope Francis told reporters, "today, officially, the church had declared that the use or possession of nuclear weapons is immoral."

And regarding the death penalty, he said, "we are close" to declaring it immoral because people's consciences have developed.

A church that does not allow its teaching to develop does not remain the same, it "goes backwards," he said. "That's the problem with many who call themselves traditionalists; they aren't traditional, they are 'backwardists.' They are going backwards."

In such cases, he said, people are not embracing and sharing the "living faith," but rather "the dead faith of the living."