AI, Machine Learning, Deep Learning and Generative AI

"AI" gets used for everything from spam filters to ChatGPT. Before we look inside a chatbot, it helps to know how the main terms fit together — they are not four different things, but circles inside circles.

Four terms, one picture

• Artificial intelligence (AI) — the whole field: building computer systems that do tasks we would normally say need human intelligence, such as understanding language, recognising images or making decisions.
• Machine learning (ML) — a part of AI. Instead of a programmer writing every rule, the system learns patterns from examples (data).
• Deep learning — a part of machine learning that uses large neural networks with many layers. It powers modern speech recognition, image recognition and language models.
• Generative AI — deep learning models that create new content: text, images, audio, code. ChatGPT, Claude and Gemini are generative AI.

Every generative AI system is deep learning; every deep learning system is machine learning; every machine learning system is AI. Not the other way round.

Rules versus learning

Older software follows rules a person wrote. A learned system finds the rules itself from examples:

# Rule-based: a person writes the rule
def is_spam(email):
    return "free money" in email.lower()

# Machine learning: the model learns the rule from labelled examples
# (illustrative — the training step is what a library like scikit-learn does)
examples = [
    ("Claim your FREE money now", "spam"),
    ("Meeting moved to 3 pm", "not spam"),
    # ...thousands more
]
# model = train(examples)
# model.predict("You won a prize!")  ->  "spam"

The rule-based filter misses "fr33 m0ney"; a model trained on enough examples can still catch it, because it learned the pattern, not one exact phrase.

You already use AI every day

• Email spam filters and phone face unlock
• Video and shopping recommendations
• Voice assistants and automatic captions
• Chatbots that write, summarise and explain

Key takeaways

• AI ⊃ machine learning ⊃ deep learning ⊃ generative AI.
• Machine learning means learning patterns from data instead of hand-written rules.
• Chatbots like ChatGPT are generative AI built on deep learning.