color ramp not visible on object

How do I apply a diffuse color ramp to an object without adding a texture?

No way, imo. Color ramp would be some way to impact/change simple/plain color applied, to modify that. What else would you think of to accomplish this? Just another set of data - texture.

under ‘Diffuse’
right next to ‘intensity’ there is a check-box that say ‘Ramp’

My bad then… For not looking on buttons; somehow thought of Texture having this. Then again in the end, isn’t it the same - texture, only built-in one?