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 
Earth is a sphere inferred by reasoning from fact that tall trees cannot be seen (Lalla, 2036), ships disappear over the horizon, horizon is circular.

उपमान 
analogy 
earth is round LIKE a kadamba flower

शब्द 
word, [reliable] testimony 
"तद विदो विदु:" “so say the learned” 