A Path to Steam
Intelligence broadly measures brainpower, including creativity, intuition, memory, perception, reason, sanity, and willpower. It rules your basic ability with all “mental” skills –
sciences, social interaction, magic, etc. Any wizard, scientist, or gadgeteer needs a high IQ first of all. The secondary characteristics of Will (p. 16) and Perception (p. 16) are based on
IQ, Sentience, and Sapience
Sentience is self-awareness. Any being with a GURPS IQ of at least 1 is sentient by definition. To create nonsentient beings – plants, brainless clone bodies, etc. – take IQ 0, for -200 points. Nonsentient creatures cannot learn skills or have any purely mental traits.
Sapience is defined as the ability to use tools and language. In GURPS, this requires at least IQ 6. Those with IQ 5 or less cannot learn technological skills (see p. 168) or possess Languages (see p. 23) – not even the initial Language that most characters get for free. They can still communicate primitive concepts (such as hunger or danger) through gesture or
vocalization, and may be trained to respond to a few commands (see Pets and Trained Animals, p. 458).