Ernst Haeckel

The ethical principles we live by should be based on reason and empathy, not dogma.

The universe does not exist for us; we exist within the universe.

Every form in nature, however humble, possesses an inherent beauty.

The greatest challenge for humanity is to live in harmony with nature.

The wonder of life lies in its continuous renewal and transformation.

To understand life, we must study its origins and its evolution.

The human brain is the most complex and fascinating organ in the known universe.

The pursuit of scientific knowledge is a spiritual quest.

The only true religion is the religion of nature.

The interconnectedness of all living things is a profound truth.

Our existence is a fleeting moment in the grand cosmic drama.

The beauty of the microscopic world is as profound as the beauty of the macroscopic.

The ultimate reality is matter and energy, constantly interacting and transforming.

The human species is a temporary phenomenon in the long history of life on Earth.

Man is a vertebrate, a mammal, a primate, and a monkey.

The soul is merely a sum of physiological functions.

There is no such thing as a 'free will' in the ordinary sense of the word.

Religion is a product of human imagination, a myth, a dream.

God is an 'ideal gas' filling the universe.

The 'missing link' between apes and humans is a hypothetical creature, Pithecanthropus alalus.