Mananeeya Eknathji says in the story of development of human being, there are many landmarks which he crosses. Slowly from total dependance he reaches the stage where he is self-dependent. Eknathji says :
A child, when it reaches adulthood, adds a new dimension to its life. Adulthood is a landmark in the development of the child into manhood. His physical and mental powers are fairly well developed. He now knows how to handle a situation. Now he has become a rational animal. He can take care of himself without anybody's help. As is said in Hindi now he has reached the age where it is said, "Ab isane hosh sambhale!" "He can guard his own interest!"
Mananeeya Eknathji here tells that man has grown. But until he starts using buddhi - intellect, though grown up, he would continue to be an animal. Usage of Buddhi makes him different. This gives him a choice to be different from animal and make life purposeful. Quoting a Subhashita, he says :
Man is an animal no doubt, but he is a rational animal. Reason is something which is a special gift to him as compared with other animals. As is said in Sanskrit Subhashita.
Buddhirhi tesham Adhiko vishesho Buddhyavihina Pashubhi Samana
The freedom that a human being has been given is in usage of Buddhi and so Eknathji says :
But this intellect is a double-edged sword. If properly used, it leads a man to become a superman, but if wrongly handled, it makes a man more ferocious than an animal. Animals also possess intelligence, but it is just to satisfy their four natural instincts. When they are satisfied, animals do not care for the world. But with his intelligence, man plays havoc. Animals do not think of tomorrow, but man thinks of storing up not only for tomorrow, but for day after tomorrow also, and in order to satisfy this desire of self-preservation, he indulges in exploitation of every kind.