Steph Magowan, MA, MSc
Royal Holloway, University of London



Alcmaeon of Croton remains one of the lesser known Presocratic writers, not only because of the sparse nature of his extant work but also because of his fragmentary treatment in modern scholarship. He is mentioned in passing but rarely fully examined, often even excluded entirely in work dealing with the Presocratics. More recently he has enjoyed renewed interest from the medical community, where he has been identified as an early pioneer of neuroscience, psychology, and dissection.1

Alcmaeon was from Croton, a prosperous colony in Magna Graecia founded c. 710 BC. It was a significant intellectual center in the south of Italy owing to both its medical reputation and Pythagorean association.2 In his Histories, Herodotus praised the colony’s medical expertise, declaring that “the best physicians in the Greek countries were those of Croton.” (3.131). It is evident from Alcmaeon’s work that he was experienced in physiological and medical matters; Diogenes Laertius identifies him as writing “mostly concerning medicine, nevertheless sometimes investigates natural causes” and it is likely he belonged to the famed medical school at Croton.3 It was known for its highly empirical approach, based on practical teachings, and as such has been considered the antithesis of the Pythagorean school also established there.4

It is clear that Pythagoreanism would have been a prominent feature of Alcmaeon’s life in Croton, though he was not himself a Pythagorean. Although Diogenes Laertius reports that Alcmaeon was a pupil of Pythagoras, the depiction of master/pupil relationships within the doxographical tradition has been long recognized as unreliable. Diogenes’ claim at the very least dates their interaction between Pythagoras’ arrival in Croton c.530BC to his death in 495BC, thus placing Alcmaeon as active at the turn of the century. The doubt over his position as a Pythagorean need not entirely render this information erroneous; it is plausible that his activity during this period is one of the major contributing factors to his Pythagorean association. Estimations of Alcmaeon’s date vary widely from the sixth to even the fourth century. From the surviving evidence, it is most likely he was active contemporaneously with Pythagoras, writing before both Parmenides and Empedocles.5

Alcmaeon’s work illustrates a methodology more aligned with the natural enquiries of the Ionian natural philosophers, separate from the religious influence of Pythagorean doctrine. His interests are wide-ranging and incorporate physiology, embryology, zoology, astronomy, and metaphysics. A brief fragment theorizing on health is perhaps the most famous of Alcmaeon’s extant work, owing to its impressive metaphorical content and insightful attribution of disease to natural, rather than supernatural, causes:

Alcmaeon holds the sustaining cause of health is the equilibrium (isonomia) of the qualities: wet and dry, cold and hot, bitter and sweet and all the rest; the sole rule of one (monarchia) is productive of disease, for this predominance produces destruction. He claims that disease arises in some cases due to an excess of heat or cold, in some from abundance or deficiency of nourishment, and in others on account of the blood, marrow or brain. Added to these are sometime exterior causes, quality of water or soil or toil, or anything relatable. Health is an even blending of the qualities.6

The Greek term isonomia predominantly refers to the equal sharing of political power; a comparative use in Herodotus places it in direct comparison to both tyranny and democracy.7 Alcmaeon uses this terminology to emphasize that it is an ongoing state of equilibrium that ensures the body is in good health; he further expands the political metaphor by describing the sole rule (monarchia)of any one quality as entirely destructive of this equilibrium. This theory is considered to have been widely influential, most directly on the Hippocratic notions of health as an equality and later more developed humoral theories.8 The blood, marrow, and brain are particularly noted as bodily locations by which disease may be caused (perhaps considered as the sites most susceptible to a qualitative imbalance), indicating Alcmaeon’s wider interest in neurological matters. He understands that health is not however solely determined by internal factors; his recognition of external factors such as the quality of water and the soil is also notable. This combination of internal and external causes blends together the physical and more metaphysical explanations for disease, appropriately reflecting Alcmaeon’s philosophical and medical experience.

Several accounts reference Alcmaeon’s innovative proposition of an encephalocentric model in which the brain, as the governing faculty in the body, oversees and co-ordinates the information provided by the senses:

Alcmaeon holds that the governing faculty resides in the brain; by this we smell as it draws the odors into itself by the process of respiration.9

All the senses are somehow closely linked to the brain, for they are maimed whenever it is moved or alters its position, as it blocks up the passages through which the sensations occur.10

There are two narrow pathways containing natural air which emerge from the seat of the brain, in which is situated the highest principal power of the soul, to the cavities of the eyes.11

He identified the sensory organs as being directly and physically connected to the brain through poroi,passages”, which link the two together. These passages serve as an important conduit between the brain and the rest of the body; sensory functions are dependent on the brain in order to fully operate, for any abnormal movement of the brain results in the deprivation of sensory function as the passages become blocked. Alcmaeon’s claim that all senses are connected to the brain has been cited as evidence of his investigation by dissection, and has also been used to credit him with the discovery of the optic nerve.12 Chalcidius also reports that Alcmaeon was the first to dare to examine by dissection, emphasizing the innovative and unparalleled nature of such an action. Dissection may have been an integral part of Alcmaeon’s empirical approach, but what type of dissection (vivisection, autopsy) is not specified and nor is the subject (human, animal).13 Chalcidius’ account is problematic in that he conflates Alcmaeon, Callisthenes and Herophilius in later lines with regards to dissection, thus making it difficult to determine which individual he was describing. That Alcmaeon performed any sort of dissection on a level equivalent to the later Alexandrians is unlikely, though does not entirely remove the possibility he practiced some form of anatomical investigations.

Alcmaeon was the first of the Presocratic writers to have conducted any scientific enquiry into the nature of the reproductive process, and his work on embryology retains a close association with his interest in the brain:

Alcmaeon holds that sperm is a portion of the brain.14

Alcmaeon claims that the head, within which is the governing faculty, is the first to be fully formed within the womb.15

That he believed sperm to be derived from the brain can be easily aligned with the focus throughout Alcmaeon’s work on the significance of the brain in bodily processes. His claim is certainly intended on a material level, with the sperm itself considered to be an extension of the physical matter of the brain. Alcmaeon’s emphasis on the sperm as originating in the brain would likely have been an extension of his encephalocentric model and his wider epistemological theories; as the human intellect is derived from the brain, that which is responsible for creating human life must also contain this intellect. Similarly, the hegemony of the brain also appears again as explanation for why the head is the first body part to develop in the womb. It is clear that the centrality of the brain was significant to Alcmaeon in a physiological context, and permeated throughout his philosophical and medical work.  

Alcmaeon’s neurological preoccupation is aptly illustrated in Phaedo 96b, in which Socrates alludes to Alcmaeon, as well as several other Presocratic philosophers:

Do we think with blood, air, fire, or none of these, and does the brain provide our sense of hearing, sight and smell, from which come memory and opinion, and from memory and opinion which has become stable, comes knowledge?16

Such reference indicates not only that Alcmaeon’s work included a wider account of the interaction between the brain, the senses, and the processes of thought, but also that his views were popular enough to have been recognizable by way of one word – the brain.



  1. G. Celesia, ‘Alcmaeon of Croton’s Observations on Health, Brain, Mind and Soul’, Journal of the History of Neuroscience, 21, 4 (2012): 409-426; R. Crivellato, 'Soul, Mind and Brain: Greek Philosophy and the Birth of Neuroscience', Brain Research Bulletin 71 (2007): 327-336.
  2. W.A. Heidel, ‘Pythagoras and Greek Mathematics’, AJP 61, 1 (1940): 1-33.
  3. Diogenes Laertius, Lives of the Eminent Philosophers VIII 83.
  4. D. Teti, Alcmaeone e Pitagora, Liviana 1988: 55ff.
  5. Though they would have been contemporary at some point; cf. M. Schofield, ‘Pythagoreanism: Emerging from the Presocratic Fog’, in C. Steel (ed.) Aristotle’s Metaphysics Alpha, Oxford 2012: 141-166; O. Primavesi, ‘Aristotle’s Metaphysics Alpha A New Critical Edition’, in C. Steel (ed.) Aristotle’s Metaphysics Alpha, Oxford 2012: 385-516; L. Zhmud, Pythagoras and the Early Pythagoreans, Berlin 2012: 122 recognises an “indisputable influence of Alcmaeon on Parmenides.”
  6. DK24B4, all translations by author unless otherwise noted.
  7. Herodotus, Histories 3.80-3.
  8. J. Mansfeld, ‘The Body Politic: Aetius on Alcmaeon on isonomia and monarchia’, in V. Harte and M. Lane (eds.) Politaea in Greek and Roman Philosophy, Cambridge 2013: 78-95.
  9. DK24A8
  10. DK24A5
  11. DK24A12
  12. R.W. Doty, ‘Alcmaeon’s Discovery that the Brain Creates Mind: a revolution in human knowledge comparable to that of Copernicus and Darwin’, Neuroscience 147 (2007): 561-8.
  13. J. Longrigg, Greek Rational Medicine: Philosophy and Medicine from Alcmaeon to the Alexandrians, London 1993: 60.
  14. DK24B13
  15. DK24B13
  16. G. Grube, trans., Plato: Five Dialogues, Indianapolis 2002: 134.


Steph Magowan, MA, MSc, is currently completing a PhD in classics at the University of London. Her current research examines how theories of mind, soul and brain developed in Presocratic philosophy and early Greek medicine. She is particularly interested in how these early writers account for psychological disorders, and their emphasis on the naturalistic and internal origins of such afflictions. She also works on the reception of Greek thought in both the Roman philosophical tradition and the medical literature of the nineteenth century.