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When Facebook chief technology officer Mike Schroepfer welcomes new engineering recruits to the social network, the first thing he talks about is the massive criticism facing the company over the past few years.

“It’s like, ‘Hi, welcome to Facebook, let me show you a bunch of news headlines of people criticizing us,” Schroepfer tells Fortune. “And what I tell everyone is the criticism is warranted.”

Working at Facebook during this tumultuous time has included multiple privacy debacles, the spread of misinformation, and various other unpleasantries that have caused Schroepfer to consider the potential unintended consequences of the company’s technology—and the role of engineers to safeguard platforms like Facebook from people with bad intentions.

“As optimists and technologists building, it’s hard to assume bad intent, and that’s exactly what you have to do to plan for these things,” Schroepfer says referring to people who are trying to exploit the social network for political or economic gain.

“We’re operating something on massive scale, you bear a huge responsibility—people should scrutinize everything you do, and our job is to prevail in the face of that scrutiny and that requires us to do a lot of hard work,” Schroepfer says he tells his hires.

These past few years have changed Schroepfer, as he revealed in an emotional interview earlier this summer in The New York Times, which prompted some backlash. The Facebook executive’s response: “That’s fine.”

“I’m fighting hard to retain my optimism while coupling with a much deeper sense of sort of realism about the harms that can happen,” he says.

Schroepfer, an artificial intelligence expert, has been staffing up recently to because Facebook has on an array of projects in its pipleline, in addition to his work building A.I. systems that can filter fake news. Here are some of the things the company is working on:

Virtual reality hand-tracking

Facebook’s forthcoming update that enables its Oculus Quest virtual reality headsets to track hand movements has required a lot of artificial intelligence to make it possible. Although the Quest device has cameras to help it recognize a person’s hands, it’s not possible for the cameras to capture all of the various angles when someone moves their hands around in a virtual world. To accommodate, Facebook had to build an A.I. model that could recognize hand movements to help the cameras out.

Artificial intelligence chips

Regarding the current boom in startups creating computer chips designed for to aid A.I.-related tasks, Schroepfer says “it’s a really interesting time for hardware.” This is because, he says, “Moore’s Law is dead,” referring to the notion that the number of transistors on a computer chip doubles every two years.

Now there’s an increasing amount of players trying to create the next game-changing semiconductor. Schroepfer commends Nvidia, the maker of the graphical processing units (GPUs,) for recognizing as early as 2004 that its chips could be used for other tasks besides making video games look prettier. Nvidia’s GPUs have since become the leading computer chips used to train neural networks.

Good ol’ CPUs

Although Facebook uses tons of GPUs to train it many A.I. systems, it also uses conventional CPUs for some heavy-duty tasks, Schroepfer says. To train giant neural networks that are good at “click predicting,” Facebook uses “very large fleets of CPUs” that allow it to crunch information more efficiently than even the beefiest GPUs that top out at 32 GBs.

Combating the rise of deep fakes

Facebook recently said it would fund a competition in which researchers would develop the best ways to detect so-called deepfakes, which are realistic looking videos intended to fool or mislead people. As part of the competition, Facebook said it would create a database of deepfake videos to help researchers develop techniques to detect what’s real and what’s not.

Coincidentally, this Tuesday Google said it would also contribute to efforts to combat the rise of deepfakes by releasing its own giant dataset of deepfake videos to A.I. researchers. Regarding the Google deepfake datasets, Schroepfer tells Fortune his hope is to merge the datasets so the Facebook-funded competition, overseen by the non-profit Partnership on AI, will have more fake videos to analyze.

While deepfakes are not a clear issue on the platform today, Schroepfer says, “if I’ve learned anything in the last three years, I don’t want to be unprepared for something.”

“I’d rather be ready to go with tools that I don’t need to use, than be in a situation especially with—say, the 2020 U.S. elections—where it becomes an issue and I haven’t invested in the technology to defend against it,” he says.