(If Friedrich Nietzsche made “You are what you eat” the cornerstone of his thinking, what would he have thought of reports of horse meat being found in European ground beef?: shardcore.org)

All of us have heard an age-old piece of wisdom, “I am what I eat.” As late as the 19th century, Friedrich Nietzsche took this dictum literally and turned it into a cornerstone of his physiological psychology.

National diets, in his half-playful reconstruction, gave rise to distinct patterns of digestion (or, in many cases, indigestion), which, in turn, accounted for various personality types: the ruminative-contemplative or the spontaneously active. Spirituality and the richness of inner life were correlated to a slower metabolism and inaction. More crudely put, the ethereal realm of spirit was born of the accumulation of gas in the intestines and the inability to pass it otherwise.

Today, over 100 years after Nietzsche’s death, we have very little idea of what we actually eat. The EU meat scandal is only the tip of the iceberg here; the shocking proportions of horsemeat in ground beef are but a reminder of our ignorance about the contents of our meals. Preservatives, bleaching agents, sulfites, and other chemical ingredients are even more common in food items than salt and sugar, with which they are laced in a vast majority of cases.

But, aside from the health concerns we all share, what interests me as a philosopher is a simple syllogism. If 1) we are what we eat, and 2) we do not exactly know what we eat, then it necessarily follows that 3) we do not know who we are. “Know thyself!”—another tidbit of ancient sagacity—begins with knowing what is on your plate.

Much has been made in contemporary thought of the indeterminacy of human beings. We cannot be defined in our essence, as who or what we really are, except as pure possibilities, capable of being virtually anything. Could it be the case that this sophisticated shoulder shrug is due to the indeterminacy of our diets, at least from the standpoint of the consumers themselves? Will we become something other than pure possibilities once we know precisely what it is that we are gulping down at any given moment?

To be sure, the fullest conscious knowledge of the ingredients is not sufficient to dissipate human indeterminacy. The absorption of nutrients passes below the radar screens of our mind, as does the speed of our metabolism. Some murkiness will always remain, testifying to the non-transparency of the mind’s relation to the body.

The public outcry over the mislabeled meat in the EU was not primarily motivated by health concerns, even though some of the horse meat mixed into ground beef was probably tainted with veterinary drugs harmful to humans. Instead, people felt betrayed by the food industry that created an extra layer of opacity between them and what they ate, that is to say, between them and themselves.

A tainted frozen lasagna dinner has become a symbol for something other than a cheap meal for the growing number of the working poor and those affected by the economic crisis. Every time we look at it on a store counter, we imagine it laughing at us: “You do not know the least thing about yourself, not even what it is that you put in your mouth!”

Michael Marder is Ikerbasque Research Professor of Philosophy at the University of the Basque Country in Spain. He is the author of The Event of the Thing: Derrida’s Post-Deconstructive Realism (2009), Groundless Existence: The Political Ontology of Carl Schmitt (2010) and numerous articles in phenomenology, political philosophy, and environmental thought. His most recent book is the forthcoming Plant-Thinking: A Philosophy of Vegetal Life (2013).