Besides love and sympathy, animals exhibit other qualities connected with the social instincts which in us would be called moral.

I believe there exists, & I feel within me, an instinct for the truth, or knowledge or discovery, of something of the same nature as the instinct of virtue, & that our having such an instinct is reason enough for scientific researches without any practical results ever ensuing from them.

How so many absurd rules of conduct, as well as so many absurd religious beliefs, have originated, we do not know; nor how it is that they have become, in all quarters of the world, so deeply impressed on the minds of men; but it is worthy of remark that a belief constantly inculcated during the early years of life, while the brain is impressionable, appears to acquire almost the nature of an instinct; and the very essence of an instinct is that it is followed independently of reason.

The very essence of instinct is that it's followed independently of reason.

Each one of us has a natural instinct to rise, like a flame of the lamp. Let's nurture this instinct.

Man is an animal with primary instincts of survival. Consequently, his ingenuity has developed first and his soul afterwards. The progress of science is far ahead of man's ethical behavior.