In the Brihadaranyaka Upanishad verse 3.7.23, it is mentioned

नान्योऽतोऽस्ति द्रष्टा, नान्योऽतोऽस्ति श्रोता, नान्योऽतोऽस्ति मन्ता, नान्योऽतोऽस्ति विज्ञात, एष त आत्मान्तर्याम्यमृतः, अतोऽन्यदार्तम्;
“He cannot be seen, but he is the seer; He cannot be heard, but he is the Hearer; He cannot be thought, but he is the Thinker; He cannot be known, but he is the Knower.  He is the Internal Ruler, your own immortal Atman. Everything else is destroyed except the Atman”
The subtle power who runs the body, senses and mind, when he leave them, this living body is called a dead body, he is known as Atman (soul or self )


Can one see or touch Atman (soul) ?

No, In this world objects can be categorized into two categories :
– objects which can be perceived by senses
–  objects which cannot be perceived by senses
1. This physical body is an object which can be perceived by senses, so it can be seen, touched, it has a smell, it has various qualities like tall, short,  young and old , it has color like white, brown e.t.c
2. Atman (Soul) is not an object which can be perceived by senses– We cannot see it, touch it, hear it, measure it, identify its form and qualities.