Term

Meaning

Mathematical example

प्रत्यक्ष

sense perception, empirically manifest

Ganita 13, verticality from plumb line, horizontality from water level

Indian proof of “Pythagorean theorem” (Yuktibhasa)

अनुमान

inference

Gola 6,

Earth is a sphere inferred by reasoning from fact that tall trees cannot be seen (Lalla, 20-36), ships disappear over the horizon, horizon is circular.

उपमान

analogy

Gola 7,

earth is round LIKE a kadamba flower

शब्द

word, [reliable] testimony

Manava 10.10,

"तद विदो विदु:" “so say the learned”