That which is not gross, tangible or durable is SUBTLE. * A flower, a fruit are things that can be seen, touched, smelled and tasted. They respond to our tactile senses. We refer to them as objects. They are gross. They exist in what may be termed the gross physical plane. * A flower smells. A fruit tastes. Smell and taste cannot be touched. They elude our tactile senses. While the flower and fruit are gross and physical, their smell and tastes are subtle. * One cannot see ideas. Ideas are in the subtle plane.