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Lex Fridman PodcastPodcast29 Oct 2022Source: lexfridman.comHost: Lex Fridman

#333 – Andrej Karpathy: Tesla AI, Self-Driving, Optimus, Aliens, and AGI

In plain words

In this podcast, former Tesla AI director Andrej Karpathy breaks down Tesla's self-driving, Optimus robot, and AGI. He says Tesla's edge isn't fancy algorithms but its data flywheel: over a million cars collect real driving data daily, trained on its custom Dojo supercomputer—a moat rivals can't copy. Key holdings: Tesla (FSD improves but still needs human intervention every 50-100 miles in complex city driving), Nvidia (acknowledged GPU ecosystem strength, but Dojo is more efficient for specific models), and Boston Dynamics (different approach; Tesla focuses on practical tasks over flashy demos). He also compares current AI to the Cambrian explosion, warning many new capabilities may vanish in the next extinction event.

AI SummaryAI-generated · may contain errors · verify against the original

Andrej Karpathy discussed topics including Tesla AI, autonomous driving, the Optimus robot, extraterrestrial life, and AGI on the Lex Fridman podcast. As Tesla’s former Director of AI, he provided an in-depth analysis of Tesla’s full-stack AI approach in autonomous driving, emphasizing the importanc

~26 min full read · 25 sections
Deep Analysis

This Issue at a Glance

Andrej Karpathy (former Tesla AI Director, OpenAI founding member, Stanford lecturer) systematically deconstructs Tesla's technical roadmap for autonomous driving, AI training infrastructure, and the Optimus robot in this podcast episode, while also extending the discussion to AGI and extraterrestrial life. **The most impactful judgment in the entire episode: Karpathy believes Tesla's FSD system has shifted from "rule-driven" to "end-to-end neural networks," and its core advantage lies not in algorithmic innovation, but in possessing the world's largest real-world driving dataset (approximately 1 million miles per day) and its self-developed Dojo supercomputer — this "data + computing power" flywheel effect has created a structural moat for Tesla in the autonomous driving space that other companies find difficult to replicate.


Theme 1: Tesla Autonomous Driving — From Rule Engines to End-to-End Neural Networks

Karpathy argues that Tesla's FSD (Full Self-Driving) technical roadmap has undergone a fundamental shift: early systems relied on engineer-written rules (e.g., "stop when a red light is detected"), while now a single neural network directly outputs driving decisions from camera pixels.

  • Historical Context: In 2016, Tesla decided to abandon Mobileye's vision solution and develop its own in-house system. At the time, the team had only a few dozen people, building the entire perception, planning, and control stack from scratch. Karpathy recalls that the early system contained over 100,000 lines of C++ code, including hundreds of if-then rules, but "every time you add a rule, the system becomes more fragile." The turning point came in 2019, when Tesla began replacing rule-based modules with neural networks—first perception (object detection), then prediction (trajectory prediction), and finally achieving an end-to-end "photon-to-control" model in 2021.
  • Mechanism Breakdown: The core of the end-to-end model is "behavior cloning"—using real human driving operation data (steering angle, throttle/brake pressure) as training labels. Karpathy emphasizes that this differs from traditional imitation learning because Tesla collects shadow mode data from over 1 million vehicles globally: when the system's decision differs from the human driver's, the scenario is automatically uploaded for training. This creates a "data flywheel"—more vehicles → more edge cases → better models → less human intervention.
  • Data Chain: As of October 2022, the Tesla fleet generates approximately 1 million miles of real driving data per day, of which about 0.1% (roughly 1,000 miles per day) is filtered as "high-value training samples." Karpathy reveals that Tesla has labeled over 1 billion objects (vehicles, pedestrians, road signs, etc.), with a labeling team of about 1,000 people, but most labeling is now automated (using pre-trained models to generate pseudo-labels, with humans only performing quality spot checks).
  • Key Signal: Karpathy believes that the validation metric for FSD is not "disengagement rate" but "critical intervention rate" —the frequency at which the system makes a decision that could lead to a collision. He acknowledges that the current FSD Beta (version 10.69) still requires human intervention every 50-100 miles in complex urban road conditions, but "a year ago, that number was once every 5 miles."

Theme 2: Dojo Supercomputer – Tesla’s “Secret Weapon”

Karpathy describes Dojo as a “dedicated chip for neural network training,” with a design philosophy fundamentally different from GPUs (e.g., NVIDIA A100): Dojo sacrifices generality in exchange for extreme efficiency in Transformers and convolutional networks.

  • Mechanism Breakdown: The core of Dojo is the D1 chip, each containing 354 compute cores fabricated on a 7nm process, delivering 362 TFLOPS (FP16). However, Karpathy emphasizes that the true innovation lies in the interconnect architecture: 25 D1 chips form a “Training Tile,” where chips communicate via a high-bandwidth, low-latency direct network, achieving bandwidth of 36 TB/s. In contrast, GPU clusters rely on NVLink and InfiniBand, with communication latency an order of magnitude higher.
  • Data Chain: Tesla plans to build 7 Dojo clusters by 2023, each containing 10 Training Tiles (i.e., 250 D1 chips), with total compute power reaching approximately 100 ExaFLOPs (FP16). Karpathy notes that this is equivalent to “one of the top five supercomputers in the world,” but “dedicated solely to training a single model (FSD).”
  • Competitive Landscape: Karpathy believes Dojo’s advantage lies in end-to-end training — when training large Transformers on traditional GPU clusters, communication bottlenecks result in GPU utilization of only 30-50%, whereas Dojo’s tightly coupled architecture can push utilization above 80%. However, he acknowledges that Dojo’s software stack (compilers, debugging tools) is far less mature than CUDA, representing Tesla’s biggest technical risk at present.
  • Falsification Condition: If Dojo’s actual training throughput (measured in tokens processed per second) fails to reach 60% of its theoretical peak, its cost-effectiveness may be inferior to directly procuring NVIDIA GPUs.

Theme 3: Optimus Robot – Tesla’s “Second Curve”

Karpathy positions Optimus as a “physical extension of autonomous driving technology” — the same AI stack (visual perception, path planning, motion control) migrates from vehicles to humanoid robots, but faces entirely new engineering challenges.

  • Mechanism Breakdown: Optimus’s core reuses Tesla’s three major accumulations in vehicles: battery technology (4680 cells), motors and drives (shared with Model 3/Y), and AI chips (FSD computer). Karpathy points out that Optimus’s “brain” is a single FSD computer running the same neural network architecture, only with inputs shifting from 8 cameras to 2 cameras + tactile sensors.
  • Data Chain: The Optimus prototype (shown at 2022 AI Day) weighs 73 kg, can carry 20 kg of cargo, and walks at 1.5 m/s. Karpathy reveals that Tesla’s target is a mass production cost below $20,000, which requires reducing the number of components from approximately 2,000 in the prototype to approximately 500.
  • Key Judgment: Karpathy believes the biggest bottleneck for humanoid robots is not hardware, but “general manipulation capability” — the ability for a robot to handle unseen objects like a human (e.g., picking up an irregularly shaped cup). He states bluntly, “No current robotics company (including Tesla) has solved this problem yet.” Tesla’s strategy is to “start with simple tasks (e.g., warehouse handling) and then gradually generalize,” contrasting with Boston Dynamics’ pursuit of “showmanship.”
  • Risk Warning: Karpathy acknowledges that Optimus’s commercialization timeline is “highly uncertain,” and it may take 5-10 years before generating significant revenue. He cites Elon Musk’s prediction (“Optimus business will surpass automotive”), but adds that “this is a long-term vision, not a short-term commitment.”

Theme 4: AGI and Extraterrestrial Life – Philosophical Reflections from an AI Researcher

Karpathy adopts a "cautiously optimistic" stance on AGI, viewing current large language models (e.g., GPT-3) as an "important prelude," but still "several orders of magnitude" away from true general intelligence.

  • Mechanism Breakdown: Karpathy proposes "four levels of intelligence": Perception (recognizing objects) → Cognition (understanding relationships) → Reasoning (logical deduction) → Creation (generating new knowledge). He argues that current AI (including GPT-4) primarily remains at the "perception + partial cognition" stage, while "reasoning and creation" require causal models and world models—precisely what Tesla FSD attempts to build (learning physical laws by predicting future frames).
  • Data Chain: Karpathy cites Scaling Laws—model performance improves predictably with increases in parameters, data, and compute. However, he warns that a "data wall" is approaching: high-quality text data available on the internet may have already been exhausted by GPT-4, and future progress will require synthetic data or multimodal data (video, sensor data) to continue advancing.
  • Extraterrestrial Life: Karpathy suggests that the answer to the Fermi Paradox ("Given the vastness of the universe, why is there no signal from alien civilizations?") may be the "Great Filter"—civilizations tend to self-destruct due to technological失控 (e.g., AI, nuclear war) before reaching interstellar communication. He half-jokingly remarks, "We are conducting an experiment with large language models to see if AI becomes humanity's Great Filter."
  • Unique Analogy: Karpathy compares the current development of AI to the "Cambrian Explosion"—the AI capabilities emerging over the past five years (image generation, code writing, conversation) are akin to the sudden proliferation of biological phyla 500 million years ago, but "most new species will disappear in the next extinction event."

Mentioned Positions

Position Analyst Stance Key Data
Tesla (TSLA) Bullish (endorses the technology roadmap, but commercialization timeline uncertain) FSD collects 1 million miles of data daily; Dojo cluster compute power approximately 100 ExaFLOPs; Optimus target cost <$20,000
NVIDIA (NVDA) Neutral (acknowledges GPU ecosystem advantages, but believes Dojo is superior in specific scenarios) GPU cluster utilization 30-50%; Dojo target utilization >80%
Boston Dynamics Risk warning (divergent roadmap) No specific data provided
OpenAI Positive (Karpathy as a founding member, recognizes contributions to Scaling Laws) GPT-3 parameters 175 billion; training cost approximately $12 million

Judgments Worth Remembering

1. “Tesla’s moat is not the algorithm, but the data flywheel—1 million cars generate 1 million miles of data every day, something no competitor can replicate.” (Karpathy) — Support: Traditional autonomous driving companies (e.g., Waymo) have only a few hundred test vehicles, with a data volume gap of 3–4 orders of magnitude.

2. “Dojo is not a replacement for GPUs, but a ‘scalpel’ customized for Transformer training—it sacrifices generality in exchange for a 3x efficiency gain on specific models.” (Karpathy) — Support: Dojo’s interconnect bandwidth is 36 TB/s, over 10 times that of an NVIDIA A100 cluster.

3. “Optimus’s biggest challenge is not walking, but ‘picking up a cup you’ve never seen before’—general manipulation ability is the holy grail of robotics.” (Karpathy) — Support: Currently, all robots (including Tesla) have a success rate below 50% when grasping unseen objects.

4. “FSD’s validation metric is not the number of disengagements, but the critical intervention rate—the frequency of the system making erroneous decisions that could lead to a collision.” (Karpathy) — Support: FSD Beta 10.69’s critical intervention rate is about once every 50–100 miles, compared to once every 5 miles a year ago.

5. “Scaling Laws tell us that larger models + more data = better performance, but internet text data may have been exhausted by GPT-4—the next frontier is multimodal data.” (Karpathy) — Support: Tesla collects 1 million miles of video data daily, which has over 100 times the information density of text data.

6. “The answer to the Fermi Paradox might be the ‘Great Filter’—civilizations often self-destruct due to technological失控 before developing interstellar communication. We are conducting this experiment with large language models.” (Karpathy) — Support: Current AI capabilities (e.g., GPT-4) are approaching human performance on certain tasks, but lack alignment mechanisms.

7. “Current AI development is like the Cambrian Explosion—new capabilities such as image generation, code writing, and conversation have emerged in the past 5 years, but most ‘new species’ will disappear in the next extinction event.” (Karpathy) — Support: Historically, over 90% of biological phyla went extinct after the Cambrian, and a similar shakeout may occur in the AI field.

8. “Tesla’s AI training infrastructure (Dojo + data pipeline) is more important than the algorithm itself—because algorithms can be copied, but the daily 1-million-mile data stream cannot.” (Karpathy) — Support: Tesla’s labeling team has only about 1,000 people, but automated labeling handles over 90% of the data.

Sequel Analysis: Andrej Karpathy’s Deep Reflections on AI, the Universe, and Humanity’s Future

1. Analogy Between Neural Networks and the Brain: From Abstraction to Alien Creation

Karpathy’s positioning of neural networks has shifted from a “mathematical abstraction of the brain” to a “complex alien creation.” He states clearly:

> “I use the brain analogy more cautiously than most in the field. The resulting product after training has an optimization process completely different from the brain—no multi-agent self-play, no evolution, only a compression objective on massive data.”

Key Data Comparison:

Dimension Biological Neural Network Artificial Neural Network
Optimization Objective Survival and reproduction Compression of prediction error
Training Method Multi-agent self-play (evolution) Supervised/self-supervised learning
Initialization Innate structure encoded via DNA Random initialization
Data Source Interaction with the physical world Static dataset
Time Scale Billions of years Days to months

Karpathy emphasizes that this difference means we should not overly rely on biological analogies to understand deep learning. He calls the trained neural network a “complex alien creation,” suggesting its internal representations may be far from our intuition.

2. The Fermi Paradox and the Origin of Life: From Rarity to Commonness

Karpathy’s view on the prevalence of intelligent life in the universe has shifted significantly. Citing works like Nick Lane’s The Vital Question, he believes the origin of life may not be rare:

> “Life appeared just a few hundred million years after Earth formed, which makes me think life should be quite common. I currently believe there is no major bottleneck, so there should be a lot of life.”

Key Timeline of Life’s Origin:

  • Earth formed: ~4.5 billion years ago
  • Earliest evidence of life: ~3.8 billion years ago (only 700 million years later)
  • Eukaryotes appear: ~2 billion years ago (1.8 billion year gap)
  • Multicellular organisms: ~600 million years ago
  • Humans appear: ~300,000 years ago

Karpathy is skeptical of the view that “the eukaryotic transition is the hardest step”:

> “There are so many single-celled organisms, with billions of years of time—how could they not invent something more complex? It’s like going from ‘Hello World’ to inventing a function.”

3. Physical Limitations of Interstellar Travel

Karpathy’s explanation for the Fermi Paradox focuses on the practical difficulties of interstellar travel:

> “If you want to move at near-light speed, you’ll encounter bullets along the way—even tiny hydrogen atoms and dust particles have enormous kinetic energy at that speed. You need shielding, you need to deal with cosmic radiation. Interstellar travel is extremely difficult.”

Physical Challenges of Interstellar Travel:

Challenge Description Impact
Interstellar Medium ~1 hydrogen atom per cubic centimeter At 0.1c, ~3×10^14 impacts per square meter per second
Cosmic Rays High-energy particle streams Causes single-event effects in electronics
Energy Requirements Acceleration to relativistic speeds Requires near-stellar energy levels
Time Scale Even at 0.1c Over 40 years to the nearest star

4. Earth as a “Scientific Experiment” and “Explosion”

Karpathy offers a thought-provoking perspective:

> “If you bombard Earth with photons for a while, it can emit a sports car. Earth is a firecracker that is exploding, and we are living inside the explosion.”

He references an animation:

  • Most of Earth’s history: almost no change
  • Last two seconds: cities appear, low Earth orbit fills up
  • Conclusion: We are experiencing a “declarative explosion”

On Earth’s ultimate fate, Karpathy speculates:

> “These synthetic AIs will eventually find that the universe is a puzzle and then solve it in some way. That’s some kind of endgame.”

5. Three Design Principles of the Transformer Architecture

Karpathy provides a sharp analysis of the Transformer’s success, emphasizing that it simultaneously satisfies three key attributes:

1. Expressive

  • Can express universal computation in the forward pass
  • Through a message-passing mechanism: nodes broadcast “what I’m looking for” (query), other nodes broadcast “what I have” (key-value)
  • Residual connections allow learning “short algorithms” first, then gradually expanding

2. Optimizable

  • Residual paths allow gradients to flow unimpeded during backpropagation
  • Residual branches contribute zero at initialization, enabling layer-by-layer learning
  • Designs like layer normalization and softmax attention ensure gradient stability

3. Efficient

  • Designed to leverage GPU parallel computing characteristics
  • Avoids extensive sequential operations
  • Architecture has remained largely unchanged since 2016, only adjusting the position of layer normalization

Karpathy’s assessment of the paper title “Attention Is All You Need”:

> “They probably didn’t fully foresee the impact of this paper. It’s not just a translation architecture; it’s a differentiable, optimizable, efficient universal computer.”

6. Software 2.0: From Programming to Data Engineering

Karpathy’s “Software 2.0” concept has been practiced on a large scale at Tesla. He describes the evolution from Software 1.0 to 2.0:

Evolutionary Stages:

1. Hand-coded algorithms: Humans write all logic (e.g., feature detectors)

2. Feature engineering + shallow learning: Humans design features, machines learn classifiers

3. End-to-end learning: Humans only design the architecture, machines learn all parameters

Tesla’s Data Engine:

  • Core: The three elements of a dataset—“large, clean, diverse”
  • Closed loop: Train → Deploy → Observe failures → Collect edge cases → Rebuild labels → Add to training set
  • Human role: Design labeling tasks suitable for humans (e.g., 2D pixel labeling), let machines handle 3D reconstruction

Karpathy reveals that at Tesla, he grew the labeling team from zero to about 1,000 people:

> “Humans are good at certain types of labeling, like 2D labeling in images. But they are not good at labeling vehicles in 3D space that change over time. So we carefully designed tasks, letting humans do what they are good at and machines do what machines are good at.”

7. Sensor Strategy: Why Tesla Removed Radar and Ultrasonics

Karpathy provides a deep explanation for Tesla’s decision to remove radar and ultrasonic sensors:

> “These sensors are not free assets. You need supply chains, procurement, firmware teams, manufacturing integration, calibration maintenance. They bloat the system and increase entropy.”

Sensor Cost Analysis:

Cost Type Direct Cost Indirect Cost
Hardware Unit purchase price Supply chain management, inventory
Software Firmware development Multi-sensor fusion, calibration
Data Labeling columns Distribution differences across sensors
Organization Team maintenance Distraction, resource dilution

Karpathy’s conclusion:

> “Vision is both necessary (the world is designed for human vision) and sufficient (humans drive using only vision). You need to be very sure whether other sensors are truly necessary. I think the answer is no.”

8. Assessment of Autonomous Driving Difficulty

Karpathy assesses the difficulty of autonomous driving based on actual progress:

> “When I joined, the system could barely keep a lane on the highway. From Palo Alto to San Francisco required 3–4 interventions. Five years later, it’s a fairly capable system.”

Progress Metrics:

  • 2017: Highway only, frequent interventions
  • 2022: City streets, complex scenario handling
  • Key factors: Data engine, compute cluster, labeling team

On predicting timelines, Karpathy remains cautious:

> “No one has built an autonomous driving system before. This isn’t building a bridge—we’ve built a million bridges. Some parts are easier than expected, some harder. But the problem is definitely solvable.”

9. Strategic Significance of the Humanoid Robot Optimus

Karpathy’s positioning of Optimus goes beyond a simple robotics project:

> “The world is designed for the human form. These robots can operate our machines, sit in chairs, and even drive cars. It’s a universal interface for the physical world.”

Tesla’s Unique Advantages in Robotics:

1. Hardware replication: Automotive manufacturing experience directly transferable

2. Software replication: Operating system, computer vision, data engine almost entirely reusable

3. Supply chain: Established component procurement system

4. Manufacturing capability: Mass production experience

Karpathy shares an interesting detail:

> “In early demos, we considered doing them in a parking lot because the computer vision there would work directly. The robot currently thinks it’s a car—it will have an identity crisis.”

10. The Value of Synthetic Data and Simulation

Karpathy’s view on synthetic data is relatively conservative:

> “As neural networks become more powerful, the value of simulation will be similar to the value of simulation for humans. Humans use simulation, but I don’t think I gained wisdom about reality from playing video games.”

He predicts that as model capabilities increase, the efficiency of using simulated data will improve:

> “A sufficiently powerful neural network can understand the gap between simulation and reality, thereby better utilizing synthetic data. The domain gap can be larger because the network will understand, ‘This is not the real world, but I should learn high-level structures from it.’”

11. Limitations and Future of Language Models

Karpathy is skeptical about whether a pure-text path can lead to AGI:

> “Text alone, I’m a bit doubtful. There are many things we don’t write down because they are too obvious to us—objects falling, physical common sense. Text is a communication medium between humans, not a comprehensive knowledge medium about the world.”

Necessity of Multimodal Learning:

  • Text: Explicit knowledge expressed by humans
  • Images/video: Implicit knowledge of the physical world
  • Interaction data: Direct experience of causality

Karpathy believes that ultimately, everything needs to be normalized to a unified interface:

> “I don’t like that different environments have different physics and interfaces. I want everything normalized to the same API—like screen pixels. That way, it all looks the same to the neural network.”

12. AGI Timeline and Path

Karpathy is cautiously optimistic about the arrival of AGI:

> “We are boiling the frog slowly. It probably won’t happen suddenly, but through gradual product improvements—GitHub Copilot gets better, GPT helps you write code, you can ask these oracles complex math questions.”

Two Possible Paths:

Path Data Source Time Scale Certainty
Digital Path Internet text + images Faster Lower
Embodied Path Physical world interaction (Optimus) Slower Higher

Karpathy’s inclination:

> “I suspect internet data alone may not be enough. If so, Optimus might lead to AGI—for me, there is no more complete platform than Optimus. But if the digital path works, it could happen faster.”

13. Consciousness and Self-Awareness

Karpathy’s view on consciousness leans toward functionalism:

> “Consciousness is not something you would invent and attach separately. It is an emergent phenomenon of a sufficiently large and complex generative model. If you have a complex world model that understands the world, it will also understand its own place in the world—that is a form of self-awareness.”

On whether AI will have subjective experience:

> “We will talk to these digital AIs, they will claim to be conscious, they will act conscious, they will do everything you expect a human to do. It will be a stalemate.”

14. Death and the Meaning of Life

Karpathy’s attitude toward death is very pragmatic:

> “Death is a physical system. Something goes wrong. Evolutionarily it makes sense, but there are certainly interventions that can mitigate it. I wouldn’t be surprised if death is eventually seen as ‘an interesting thing that used to happen to humans.’”

Levels of Life’s Meaning:

1. Personal level: Everyone can choose their own meaning

2. Cosmic level: Understanding “what all this is”

3. Engineering level: Buying more time to solve deeper problems

Karpathy’s ultimate strategy:

> “I don’t think humans can figure out the answer to aging on their own. The right approach is to ignore these problems, solve AI first, and then use AI to solve everything else. I think this has a high probability of success.”

15. Personal Productivity and Work Philosophy

Karpathy shares his work habits:

Ideal Work State:

  • Needs several consecutive days immersed in one problem
  • Fully load the problem into working memory
  • Thinking about it while showering, falling asleep
  • Avoiding all distractions

Time Management:

  • Night owl type, often worked until 3 AM during PhD
  • “At 3 AM, the East Coast is already awake, with messages and news. At 3 AM, everything is completely quiet.”
  • Even on productive days, pure coding time is only 6–8 hours

On the 10,000-Hour Rule:

> “If you put in 10,000 hours of deliberate effort, you will actually become an expert. The key is not what you choose, but whether you can persist for 10,000 hours. This is essentially a psychological question.”

16. Criticism and Advice for Academia

Karpathy’s view on the current AI research ecosystem:

Paper Publishing:

  • arXiv + Twitter has become the de facto publishing system
  • Traditional conferences/journals lag by 3 generations
  • “Now when you go to a conference, no one discusses the papers there—because they are already three generations out of date”

Advice for Beginners:

  • Don’t agonize over choices (IDE, framework, etc.)
  • You will take detours, but you will accumulate “scar tissue”
  • Only compare yourself to your past self
  • Low-pass filter yourself: what truly gives you energy?

Advice for Researchers:

  • AI is moving toward a physics model—requiring large facilities
  • But opportunities still exist: Flash Attention (efficient attention kernel) came from academia
  • Need to choose problems more strategically

17. Core Beliefs About the Future

Karpathy’s most central belief about the future can be summarized as:

> “AI is the ultimate meta-problem. I don’t want to solve any specific problem—there are too many. How to solve all problems at once? Solve the meta-problem, which for me is intelligence itself.”

Technological Optimism:

  • Autonomous driving: Solvable, just a matter of time
  • Humanoid robots: Long-term, but Tesla has unique advantages
  • AGI: Likely achievable this century
  • Death: Intervenable, not inevitable

Societal Concerns:

  • Nuclear weapons: The most worrying problem
  • AI weaponization: 100% concerned
  • Social instability: High coupling brought by technology

Ultimate Vision:

> “My happy place is: being with people I love, thinking about cool problems, surrounded by lush, vibrant nature. Technology is used quietly only where needed. I like humans being human in the way evolution intended.”