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But what is a neural network? | Deep learning chapter 1

But what is a neural network? | Deep learning chapter 1 on HackerTube: recommended by 16 Hacker News commenters across 14 separate months, 2017–2025.

3Blue1Brown

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3Blue1Brown's first chapter on deep learning explains what neurons and layers are and the math underlying a basic neural network, using handwritten digit recognition with visual animations.

Why Hacker News recommends it

HN treats it as the standard first stop for learning neural networks, praised for making the math intuitive.

people recommended it
16
separate months
14
strong recommendations
5
discussed on HN
2017–2025
“the visualisations and explanations of the math/concepts are so amazing”
— mandliya, Dec 2017, in “What was the best CS, SE or Math video you watched in 2017?”

What HN commenters said

19 Hacker News comments link this video. Each one links back to its thread.

6mianApr 2024Strongly recommends

For me 3brown1blue series: ▶ this video was an excellent introduction that made Andrej's videos understandable. Then I did 3 first chapters of fastai book, but found it too high level, while I was interested in how things works under the hood. Going through Andrej's makemore tutorials required quite a lot of time but it's definitely worth it. I used free tier of Google Colab until the last one. Pausing the video a lot after he explains what he plans to do and trying to do it by myself was a very rewarding way to learn, with a lot of "aha" moments.

in “But what is a GPT? Visual intro to Transformers [video]” · View on HN

superkuhApr 2023Strongly recommends

Essentially a computer neural network is just a lot of addition (and matrix multiplication) of floating point numbers. The parameters are the "strength" or "weights" of the connections between neurons on different layers and the "bias" of each neuron. If neuron Alice is connected to neuron Bob and Alice has a value of 0.7, and the weight of Alice's connection to bob is 0.5, then the value sent from Alice to Bob is 0.35. This value (and the values from all the other incoming connections) are summed at added to the neuron's negative bias. I highly recommend checking out 3blue1brown series on how neural nets, gradient descent, and the dot product (implemented as a matrix multiplication) all tie together: ▶ this video

in “State-of-the-art open-source chatbot, Vicuna-13B, just released model weights” · View on HN

spandexcajunMay 2019Strongly recommends

3blue1brown videos are probably the best equivalent. Maybe a little basic? But really, all his math videos are just ridiculously good quality. ▶ this video

in “Five Hundred and Seven Mechanical Movements (1908)” · View on HN

mandliyaDec 2017Strongly recommends

▶ this video 3Blue1Brown’s playlist on neural networks. Like other 3Blue1Brown videos, the visualisations and explanations of the math/concepts are so amazing, they give you the intuition behind the neural networks naturally.

in “What was the best CS, SE or Math video you watched in 2017?” · View on HN

hal9000xpNov 2017Strongly recommends

I'm in the same boat. For long time, I was interested in AI but at the same time intimidated by math. I'm relatively comfortable with discrete mathematics and classical algorithms and at the same time calculus and linear algebra is completely foreign to me. Also, I do not accept way to learn ML without good understanding of core principles behind it. So math is a must. A few months ago, I stumbled upon very amazing YouTube Channel 3Blue1Brown which explains math in very accessible way and at the same time I got feeling that I finally started understanding core ideas behind linear algebra and calculus. Just recently he published 4 videos about deep neural networks: ▶ this video [link] [link] [link] So my fear of ML was gone away and I'm very excited to explore whole new world for neural networks and other things like support vector machines etc

in “Ask HN: Best way to get started with AI?” · View on HN

RazenganSep 2025Recommends

A while ago I had caught up with the basics thanks to the legendary 3blue1brown and his playlist on Neural Networks: ▶ this video and other helpers like Artem Kirsanov: [link]

in “Qwen3-Next” · View on HN

Show 13 more comments
rottc0ddMar 2025Recommends

If anyone wants to delve into machine learning, one of the superb resources I have found is, Stanfords "Probability for computer scientists"( [link] ). It delves into theoretical underpinnings of probability theory and ML, IMO better than any other course I have seen. (Yeah, Andrew Ng is legendary, but his course demands some mathematical familarity with linear algebra topics) And of course, for deep learning, 3b1b is great for getting some visual introduction ( ▶ this video ).

in “Deep Learning Is Not So Mysterious or Different” · View on HN

phkahlerMay 2024Recommends

>> YouTube has always been a mixed bag As an outsider but avid reader of this stuff linked from HN, I would recommend the channel 3blue1brown. He's got several NN and AI related videos, and the couple I've seen were pretty good. ▶ this video

in “Better and Faster Large Language Models via Multi-Token Prediction” · View on HN

segmondyJun 2023Recommends

Studying C or Python is studying C or Python. Rather, study AI. Pick up python along the way, skip C. ▶ this video [link] There's tons of book, but I recommend this since it's hands on "Hands-On Machine Learning with Scikit-Learn, Keras, and TensorFlow" [link] [link] download some local LLMs and play with them along the way. Good luck.

in “Getting into AI This Summer” · View on HN

circuit10Apr 2023Recommends

If a human brain doesn’t use maths, what does it use? It’s Magic? > "training", more accurately described as references Uh, no, that's not at all how the training process works. The training process very roughly mirrors evolution/natural selection except more more direct and faster. This is a good introduction to the concept of how a computer could learn: [link] This is a more technical look at how exactly it works in more modern AIs: ▶ this video (it's a series) > If it encounters a problem it hasn't been programmed for, it cannot reason a new solution. But an LLM can? It's not as good at it as a human but it can Relevant: [link] (if you don’t want to click it it says “referring to AI models as "just math" or "matrix multiplication" is as uselessly reductive as referring to tigers as "just biology" or "biochemical reactions"”) > By your logic, video game characters must use reasoning, when no, they don't. It's maths. “By your logic, if tigers are dangerous, then bananas must be too, when no, they aren’t. It’s biology.”

in “The future of generative AI is niche, not generalized” · View on HN

ianbutlerFeb 2023Recommends

I think FastAI lesson 3 in "Practical Deep Learning for Coders", has one of the most intuitive buildups of gradient descent and loss that I've seen. * Lecture [1] Book Chapter [2] It doesn't go into the math but I don't think that's a bad thing for beginners. If you want mathematical, 3blue1brown has a great series of videos [3] on the topic. [1] [link] [2] [link] [3] ▶ this video * I've been messing around with this stuff since 2016 and have done a few different courses like the original Andrew Ng course and more.

in “GPT in 60 Lines of NumPy” · View on HN

aero-glideSep 2020Recommends

Here's a 4-part video series by 3blue1brown : ▶ this video Explains the big picture in an intuitive way

in “Bringing the Mona Lisa Effect to Life with Tensorflow.js” · View on HN

miklosmeMay 2020Recommends

If you want an extensive answer, I recommend the neural network playlist on 3Blue1Brown: ▶ this video For a quick answer, watch this segment: [link]

in “Humans Not Invited” · View on HN

dahartApr 2018Recommends

The Stanford course is pretty good. [link] For something quicker & less applied, maybe the 3b1b series on neural networks: ▶ this video

in “Microsoft makes AI training courses available to the public” · View on HN

nouveauxNov 2017Recommends

This was very timely for me and for anyone else learning, here are the first few videos of the series: ▶ this video [link] [link] (Original video) [link]

in “What is backpropagation and what is it doing? [video]” · View on HN

ocharlesOct 2017Recommends

3blue1brown is currently doing a terrific series on how neural networks work, which nicely compliments this blog post. ▶ this video

in “A Neural Network in 11 Lines of Python (2015)” · View on HN

dpoloncsakNov 2025Cites it

They can , sure...that's really just LLMs though. ML models to recognize handwriting have existed way before LLMs could call tools, though Identifying digits is like the "Hello World!" of ML ▶ this video

in “I hate screenshots of text” · View on HN

afarrellFeb 2020Cites it

I can partly understand some this based on an EE101-level control theory, a High School level model of how neurons work, and 3blue1brown's intro to neural nets[1]. However, I have a strong personal interest in developing a much deeper understanding of dopamine neurons and their role in Executive Function. Can anyone recommend a good curriculum which can take a random web developer from "Knows what a myelinated axon, a sigmoid function, and a feedback loop are" to having a solid enough background to dive into the research on this? [1] ▶ this video

in “Dopamine and Temporal Difference Learning” · View on HN

vanderZwanMar 2018Cites it

Yes, while I haven't done anything with ML myself, I heard via the 3Blue1Brown video on Deep Learning[0] that the sigmoid function isn't really that used anymore. But I figured allowing that being able to tweak the dynamic range could make it a good fit for the rescaling and recentering approach. You know what, I'll just go ahead and post a link to this article on the Unum google group, perhaps someone there can add some thoughts[1]. [0] ▶ this video [1] [link]

in “HALP: High-Accuracy Low-Precision Training” · View on HN

Topics & tags

Machine learning & deep learningRecreational & visual mathdeep learning3blue1browngradient descentvisualizationmachine learning basics