“Another example for the similarity between humans and animals is the fox the Thracians used when they wanted to cross a frozen river:

They would unleash the fox and have it go ahead before them. At the bank, the fox would lay its ear on the ice to listen if there was water running underneath and how far down. The fox would then retreat or advance according to the assessed thickness of the ice. How could we watch the fox without assuming it to have a similar train of considerations as we have on our minds? That which makes noise moves; that which moves is not frozen; what is not frozen is liquid; and what is liquid will not support any weight. What, if not common sense of some sort, leads to such a deliberate conclusion?

Some animals are more equal

It is clear enough that animals are superior to us in most of their tasks, and that our faculty to imitate them is but feeble. We are aware that our own productions, although much coarser, require substantial skills and utmost mental efforts. How come should it be any different for them? Why do we ascribe the achievements of animals to some innate, blind instinct, even though they surpass everything we are able to do with our natural and artificial means?

I contend that here is no rational explanation to believe that the moves of animals are based on compulsive natural instinct, while ours build on free choice and acquired skills. It is rather consequent to conclude that the same results are produced by equal capacities, and that the very mind and the very process that determine our actions also determine those of animals in the same measure, if not even more so. Why do we suppose them to be driven by natural instinct, while we do not presume that for ourselves?

We humans stand neither higher nor lower than other beings. Everything under the sky follows the same law and fate. Humans are bound to the laws of nature in the same way as other beings are—and that at a very mediocre position, with no privileges, and not distinguished by any tangible, essential superiority.

Stupid vanity

Our vain pride seduces us to attribute our abilities to our own faculties rather than to nature. By supposedly honoring and ennobling ourselves with acquired qualities, we leave nature’s gifts to the other living beings—a rather simple-minded deal, as I see it. How great must be our vanity to regard as below us, and condescendingly comment on, those achievements that we are neither able to comprehend nor to imitate!

I am filled with utmost admiration for the behavior I observe in guide dogs that lead the blind. I have seen them stop at certain places where alms are usually given; I have seen them pull their owners aside to prevent them from being run over by carriages or carts that would have left sufficient the space for the dogs themselves to pass. I once watched a dog that left a well-paved, smooth path along a moat to steer its owner clear of the ditch.

The superiority humans, in their conceit, congratulate themselves for is entirely unfounded. And if it is true that among all living beings, humans alone possess the freedom of unrestrained opinion and thought, enabling them to know what is and what is not, to distinguish truth from falsity, then this is an advantage that costs them dearly and hardly gives reason to boast. For this, precisely, is the source of the evils that plague humanity: sin and illness, fickleness and helplessness, even despair. 

We are obliged to a certain respect and a generally benevolent attitude towards sentient animals—and not only towards them, but also towards trees and plants. We owe justice to human beings, and kindness and goodwill to all other creatures susceptible to it. There are many relationships between them and us, and many mutual obligations.»