Large Language Models Explained: What Actually Got Us to Today's AI

Large Language Models Explained: What Actually Got Us to Today's AI

It’s easy to think AI just woke up one day. We went from clunky chatbots that couldn't understand a simple pizza order to systems that write code, compose poetry, and pass the bar exam. Honestly, it feels like magic. But the reality of Large Language Models is a lot more grounded in math, massive server farms, and a few specific breakthroughs that most people outside of Silicon Valley totally missed.

If you’re looking for a "spark of consciousness," you won't find it here. What you will find is a story about how we learned to turn the entire internet into a giant game of "predict the next word."

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The Transformer: The Engine Under the Hood

Everything changed in 2017. Before then, we used things called Recurrent Neural Networks (RNNs) and Long Short-Term Memory (LSTM) networks. They were okay. Kinda slow. They processed text like a human reads: one word at a time, from left to right. If you had a long sentence, the model would basically "forget" the beginning by the time it reached the end.

Then came the paper "Attention Is All You Need" by researchers at Google.

They introduced the Transformer architecture. This was the big one. Instead of reading word by word, Transformers look at the entire sentence—or entire pages—all at once. It uses something called "Self-Attention." Think of it like a highlighter. When the model sees the word "bank," it looks at the surrounding words to see if we’re talking about a river or a financial institution. It assigns "weights" to those surrounding words.

This allowed for massive parallelization. Because the model didn't have to wait for the previous word to finish processing, we could throw thousands of GPUs at the problem simultaneously. Speed went up. Efficiency skyrocketed.

Why Scale Suddenly Mattered

For a long time, researchers thought we needed better algorithms. We didn't. We just needed more "stuff." This is what experts call the Scaling Laws.

Rich Sutton, a pioneer in AI, wrote an influential essay titled "The Bitter Lesson." His point? Attempting to "teach" AI how humans think is a waste of time. The only thing that consistently works is leveraging massive amounts of computation. Large Language Models aren't smart because they understand logic; they are powerful because they have seen nearly every combination of words ever typed by a human.

Take GPT-3, for example. It had 175 billion parameters. Parameters are basically the "knobs" the model turns during training to get the prediction right. Compare that to GPT-2, which had only 1.5 billion. The jump in performance wasn't just incremental; it was transformative. Suddenly, the model could do things it wasn't even trained to do, like translate languages or solve math problems. These are called "emergent properties."

Nobody explicitly told these models how to code in Python. They just read enough GitHub repositories to figure out the patterns.

Data: The Good, The Bad, and The Common Crawl

Where does all this info come from? It’s not just Wikipedia.

Most Large Language Models are fed a diet of:

  • Common Crawl: A massive petabyte-scale copy of the internet. It includes blogs, news sites, and unfortunately, a lot of junk.
  • The Pile: A 825GB dataset created by EleutherAI, containing everything from PubMed papers to Enron emails (yes, really).
  • BooksCorpus: Thousands of unpublished books to help the model learn narrative flow.

But here’s the kicker: more data isn't always better. We're actually running out of high-quality human text. Some researchers at Epoch AI predict we might hit a "data wall" by the late 2020s. This is why companies are now desperately trying to license data from Reddit, Twitter (X), and major news publishers. They need the "good stuff"—text written by people who actually know what they’re talking about.

The Human Touch: RLHF

If you just train a model on the internet, it becomes a jerk. The internet is full of bias, toxicity, and straight-up lies. If you asked an early raw version of a Large Language Model how to steal a car, it would probably give you instructions.

To fix this, we use Reinforcement Learning from Human Feedback (RLHF).

Humans sit in a room and rank different outputs from the model.
"Which of these two answers is more helpful?"
"Which one is less racist?"
The model then uses these rankings to update its behavior. It’s essentially "finishing school" for AI. This is why ChatGPT feels so much more "personable" than the raw models that came before it. It’s been poked and prodded by thousands of human labelers to act like a helpful assistant.

Misconceptions: What These Models AREN'T

Let's get real for a second. These things don't have a "world model."

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When you ask a Large Language Model a question, it isn't "thinking." It’s calculating probabilities. If I say "The cat sat on the...", the model knows there's an 80% chance the next word is "mat" and a 2% chance it's "refrigerator." It’s a stochastic parrot.

This leads to "hallucinations." Since the model is just predicting the most likely next word, it will often confidently state things that are completely false if those words sound like they belong together. It doesn't have a database of facts; it has a map of word relationships.

The Energy Cost Nobody Likes to Talk About

Training these things is an environmental nightmare.

Training a single large model can consume as much electricity as hundreds of American homes use in a year. We're talking about clusters of tens of thousands of Nvidia H100 GPUs running at full tilt for months. Companies like Microsoft and Google are now scouting locations for data centers based almost entirely on access to power grids and water for cooling.

It’s a hardware arms race. If you don't have $10 billion to spend on chips and electricity, you aren't playing in the big leagues.

The Future: It’s Not Just Text Anymore

We’re moving into the era of Multimodality.

The next generation of Large Language Models isn't just looking at text. They are being trained on images, audio, and video simultaneously. This helps them understand the physical world. If a model "sees" a video of a ball falling, it understands gravity better than if it just read a physics textbook.

We're also seeing a shift toward "Small Language Models" (SLMs). Not everyone needs a trillion-parameter beast to summarize an email. Models like Mistral or Meta’s Llama series are proving that with better data pruning, you can get incredible performance out of much smaller, cheaper packages.

Actionable Insights for the AI Era

If you want to actually use this tech effectively without getting fooled by the hype, keep these points in mind:

  • Verify Everything: Treat a model output like a draft from a very fast, very confident intern who occasionally drinks on the job. Always fact-check names, dates, and citations.
  • Prompting is Context: Since these models rely on "attention," give them a lot to look at. Provide examples of the style you want. Don't just say "write a report"; say "write a report in the style of a McKinsey consultant focusing on operational efficiency."
  • Use Chain of Thought: If you have a complex problem, tell the model to "think step-by-step." This forces the model to allocate more computational steps to the logic rather than just blurt out an answer.
  • Privacy Matters: Unless you are using an enterprise version with a "no-training" clause, assume everything you type into a major LLM is being used to train the next version. Don't feed it your company’s secret sauce.
  • Focus on Logic, Not Just Grammar: These models are great at making things sound pretty. They are less great at complex math or symbolic logic. Use them for drafting and brainstorming, but keep a human in the loop for the final "truth" check.

The road to today’s AI wasn't paved with "silicon brains." It was paved with a clever math trick called Attention, an insane amount of internet data, and more electricity than most small countries use. Understanding that doesn't make the tech any less impressive—it just makes it understandable.