Core Concepts

What is AI (and what it is not)

Machine learning vs deep learning vs generative AI — vocabulary, limits, and when not to use an LLM.

35 min

Why this article exists

Andrew Ng’s AI for Everyone starts with terminology and limits. ShipAI engineers still need that bridge: stakeholders say “AI” when they mean a spreadsheet rule, a classifier, or ChatGPT. This page is the shared vocabulary before tokens and transformers.

Misnaming the problem causes bad architecture: teams buy an LLM for a deterministic eligibility rule, or train a custom model when a prompt + retrieval would ship in a week.

Three nested ideas

flowchart TD
  AI[Artificial intelligence] --> ML[Machine learning]
  ML --> DL[Deep learning]
  DL --> Gen[Generative AI / LLMs]
Term Plain meaning Typical artifact
AI Systems that perform tasks that look intelligent Broad product label
ML Learn patterns from data instead of hand-coded rules Classifier, ranker, forecaster
Deep learning ML with multi-layer neural nets Image net, speech model, LLM
Generative AI Models that produce new text/images/code/audio Chatbots, copilots, image tools

Ship rule: Prefer the most specific true label. Calling everything “AI” hides whether you need labeled data, a retrieval index, or just better UX.

Narrow vs general (product language)

Phrase Useful meaning Trap
Narrow AI Good at a scoped task (spam, ranking, extract fields) Sounds “small” — can still be critical path
General / frontier models Broad skills via large pretrained LLMs Not automatically correct on your facts
AGI Speculative human-level generality Not a shipping milestone for your roadmap

Build products with narrow success metrics, even when the engine is a general model.

What today’s LLMs are good at

  • Drafting, summarizing, transforming text and code
  • Tool-using agents when tools are reliable and scoped (Agents and ReAct)
  • Retrieval-augmented Q&A over your docs (with evals) (RAG building blocks)
  • Structured extraction when schemas are validated (Structured outputs)
  • Classification / routing when a golden set says they beat a baseline

What they are bad at (without extra systems)

  • Guaranteeing facts without retrieval or tools
  • Exact arithmetic / inventory counts (use code tools)
  • Fresh private knowledge not in context or an index
  • Decisions that require auditability and zero hallucination risk alone
  • Long-horizon autonomy without stop policies and HITL
flowchart TD
  Job[Job to be done] --> Q1{Need creativity / language?}
  Q1 -->|No| Rules[Rules / SQL / classic ML]
  Q1 -->|Yes| Q2{Need private facts?}
  Q2 -->|Yes| RAG[RAG / tools]
  Q2 -->|No| LLM[LLM prompt]
  RAG --> Eval[Eval gate]
  LLM --> Eval
  Rules --> Ship[Ship]
  Eval --> Ship

Supervised, unsupervised, reinforcement (one slide)

  • Supervised — learn from input→label pairs (spam / not spam)
  • Unsupervised — structure without labels (clustering, embeddings)
  • Reinforcement — learn from rewards (RLHF for preference alignment)

LLMs use all three across their lifecycle: unsupervised-ish pretrain on text, supervised fine-tunes, preference/RL stages. Product engineers mostly touch the last mile: prompts, RAG, light fine-tunes, and evals — see LLM project lifecycle.

When not to use an LLM

Situation Prefer
Deterministic policy (“if amount > X”) Rules engine
Stable labels + tabular features Classical ML (Classical ML literacy)
Exact counts / money math Code / DB aggregates
Need citations to private docs RAG + citations, not “just ChatGPT”
Regulated decision with hard audit Human + constrained tools; not free-form generation alone

Failure modes of “AI” projects

Failure What it looks like Fix direction
Solution looking for a problem Cool demo, no metric Write success metric first
Wrong tool LLM for eligibility rules Rules / workflow
No evals “Looks good in Slack” Golden set + gate
Data denial Want magic without corpus or labels Scope to prompt-only or collect data
Overclaim Marketing says “accurate” Measure faithfulness / task success

Glossary

Term Meaning
Model Learned function mapping inputs → outputs
Inference Running a trained model on new inputs
Hallucination Fluent output not grounded in facts/evidence
Baseline Simple system you must beat on metric + cost

Micro-project

List three work problems that are ML, three that are rules, and three that should not use AI. For one ML candidate, write a one-line success metric.

What happened in AI (till now) and ML/DL literacy. Next Core Concepts: Classical ML literacy, then Tokenization.

Project checklist0/3 done