A Difference of Degree and Not Kind

“The difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind.”  — Charles Darwin

It’s almost the end of the month of May.

On May 31 of 1836, the HMS Beagle rounded the southern tip of African and landed near Cape Town. In four short months he would be back home in England. During his few days at Cape Town, the 24 year old Darwin met with astronomer Sir John Herschel to discuss various subjects. Only a few months previously, Herschel had written Charles Lyell regarding Lyell’s seminal “Principles of Geology.“, the first book of modern geology. Both men would play an influential role in Darwin’s live and the  development of “On the Origin of Species” and “The expression of the emotions in man and animals.”

If we choose to let conjecture run wild, then animals, our fellow brethren in pain, diseases, death, suffering and famine – our slaves in the most laborious works, our companions in our amusements – they may partake our origin in one common ancestor – we may be all netted together. – Charles Darwin

The importance of Darwin’s contribution to biology and the study of animal behavior and eventually to the way he have come to see animals cannot be overstated. More than anyone, it was Darwin that established the direction of comparative psychology. An approach that does not ignore the biological – and therefor mentalistic – continuity between human and non-human animals, a view shared by Marc Bekoff, Jaak Panksepp, Michael Tomasello, and Temple Grandin, Karen Pryor, Ian Dunbar, David Hume,  Jane Goodall and more.

Over the last few decades we’ve come to realize that many “human” traits – tool use, culture, language, empathy, numeracy, syntax – are not uniquely human.  Not to say that humans are not unique. Or that dogs are not unique. Both are unique but still share a common emotional framework.  That animals have emotions is no longer a controversial statement. That we share many mentalistic processes has become self evident.

Being aware of the emotional live of animals, specially our companion animals, can influence the way we deal with them. They feel fear like us. They feel pain like us. They feel pleasure like us. For most people, inflicting pain and suffering is easier if the victim is not like the perpetrator. Defining the victim as inherently differently makes mistreatment easy. Science has shown that animals are very much like us; making that acknowledgement is the first step toward a kinder treatment of animals.

For setting us on that path, Darwin has my eternal thanks.

PS. Be nice to people too!!! We too are animals 🙂

N.B.  Darwin and Herschel eventually ended up buried beside each other and can be found at Westminster abbey


Darwin’s whole collection of books, letters, articles are available in multiple formats and languages. Here  Less complete but more format options for you favourite ebook reader can be found Here


1872. The expression of the emotions in man and animals. London: John Murray. Text Image PDF F1142

1873 [1872]. The expression of the emotions in man and animals. New York: D. Appleton. Image PDF F1143

1890. The expression of the emotions in man and animals. London: John Murray. 2d ed. Edited by Francis Darwin. Text Image PDF F1146


1873. Het uitdrukken der gemoedsaandoeningen bij den mensch en de dieren. Image PDF F1182


1874. L’Expression des émotions chez l’homme et les animaux. Image PDF F1184

1890. L’expression des Émotions chez l’homme et les animaux. 2d ed. Text Image PDF (Interim images from Bibliothèque nationale de France http://gallica.bnf.fr) F1186


1872. Der Ausdruck der Gemüthsbewegungen bei dem Menschen und den Thieren. Image PDF F1187

1877. Der Ausdruck der Gemüthsbewegungen bei dem Menschen und den Thieren. 3d ed. Text Image PDF (Provided by http://www.biolib.de/) F1189

Polish 1873. Wyraz uczuć u człowieka i zwierząt. Image PDF F1203

Spanish [c. 1902] La expressión de las emociones.


2 thoughts on “A Difference of Degree and Not Kind

  1. Pingback: Rats, Chocolate and Source Memory | Science of Dogs

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