In 1888, Wilhelm Roux, a German embryologist, argued that frog embryos developed by pure physical mechanical methods. Driesch objected to the "pure physical mechanism" view of Roux, and went on to repeat his experiments.
In 1891, Driesch, at the Naples Zoological Station, took a sea urchin, at the four-cell zygote stage level of reproduction, separated the four cells, and found that each of the four cells developed into a new urchin.
In 1904, Driesch, in his Concepts of Nature and Judgments of Nature discussing: thermodynamics (17+ pgs), entropy (18+ pgs), energy (84+ pgs), and biology (34+ pgs), using formulas, and citing Clausius, Helmholtz, and the "free energy" equation of Helmholtz, and Ostwald. The Nature review abstract of this book is as follows:
- “This book deals chiefly with three topics. Starting on a Kantian basis, it seeks to state the a priori principles of pure physical science. A priori is conveniently defined as “independent of the amount of experience.” Next, the leading principles of “energetics” are discussed, and their relation on the one hand to the a priori principles of pure physical science, and on the other hand to the ordinary laws of thermodynamics. Incidentally, the “laws” of conservation (of substance and the like) are examined, and entropy has a good deal of attention. Last of all the results attained are carried over to a discussion of biology. The point of view is neo-vitalistic. It would be hazardous to say that the author has run to earth the x which is the object of all our search, the vital principle or whatever other name may be applied to it; the term which he uses is the blessed word entelechy.”
When he published this, Ostwald’s model of “energetics” was in favor, so Driesch employed this model, because he thought it would make his vitalist theory consistent with science, to some degree. In the aftermath of the "energetics debate", e.g. Boltzmann's suicide (1907) and Ostwald recanting his disbelief in atoms (1909), after which entropy models and time-irreversiblity became the new standard, Driesch backtracked, to some extent, and the term "causal factor", along side his "entelechy", to account for entropy, or something along these lines.
Driesch, however, rejected the energetic view of things, favoring with the metaphysical side of the fence; his translator comments on this as follows:
- “In 1908 to 1913, Driesch's position towards mechanical physics and metaphysics changed. The change is due to the fact that he no longer believes that qualitative energetics can take the place of a real theory of matter, whether mechanical or electrodynamical. He now regards a critical metaphysic as possible, and no longer supports any kind of conceptual phenomenalism as the final word of philosophy.”
- — Charles Ogden (1914), “Translators Preface” to The History and Theory of Vitalism (pgs. v-vi)
Driesch argued, supposedly, that the operation of entelechy, as occasion requires, suspends the operation of the second law of thermodynamics. Where he says this, it remains to be seen? In his The History and Theory of Vitalism (pg. 7) he uses the term "thermodynamics" once, alluding to the premise that in the biological sciences "chance" events and discoveries are important, but the discussion of very superficial, and he does not seem to reject thermodynamics directly, but only indirectly?
Entelechy | X-Agents
In c.1910, Driesch dubbed this nonmaterial life force by the name "entelechy", an "inner teleology"; the notion of “entelochies” conceived as a sort of inner goal-directed agent hypothesized to be the mechanism behind developmental organism traits. He occasionally also employed the term "x-agent" in a synonymous fashion. This was conceptualized as a nonmaterial “life force” that supervised and regulated embryological development; the following is one take on his entelechy:
- “In the main, Driesch’s ‘entelechy’ remained a spaceless, timeless, and manifold whole, whose individual parts were themselves whole, manifold, and individual, but in contrast with the former, also, material, which means, existing in space and time.”
- — Horst Freyhofer (1982), The Vitalism of Hans Driesch (pg. 166) 
In 1914, Driesch, having given several lectures on this, at several universities, began to solidify his views as follows:
- “Whenever anything is produced by nature or by art, according to Aristotle, there arises something which is potentially (δυναμει οv) through something which is in actuality (εντελεχεια οv). The question is as to the words dynamis and entelechy. By dynamis is not really meant what in modern terminology would be called ‘potentiality’ or ‘potential energy’, at least not that only, and in any case not in the passage to which we have drawn attention. The concept is much wider: by dynamis the statue is already contained in the block of marble, and indeed it is in this sense, as we shall see later on, that Aristotle uses the word in our passage. Entelechy is that which ‘is’ in the highest sense of the word, even if it is not strictly a realized thing; in this sense the statue, before it is realized, exists in the mind of the sculptor. We can see that the concept of entelechy rather than that of dynamis corresponds, though not completely, to the modern concept of the potential.”
- — Hans Driesch (1914), The History and Theory of Vitalism (pgs. 13-14)
Here, we see Driesch, in his digression on Aristotle’s “potential and actuality” categories, convolutes a number complex topics together; and, therein, seemingly, attempting to sell the notion that the "idea" of a sculpture, in the mind of an artist, is "entelechy", being what we would no call the electromagnetic force, stored in the quantum electrodynamic hydrocarbon structure of the mind, quantified in terms of what we now call the "thermodynamic potentials" of existence, conceptualized as waves of Gibbs energy moving or rolling through the minds of society; visualized on energy landscapes.
Soul | Aristotle
In 320BC, Aristotle defined the soul as follows:
- “But ‘actuality’ is so spoken of in two ways, first as knowledge is and second as contemplation is. It is clear then that the soul is actuality as knowledge is; for both sleep and waking depend on the existence of soul, and waking is analogous to contemplation, and sleep to the possession but not the exercise of knowledge. Hence, the soul is the first ‘actuality’ of a natural body which has life ‘potentially’.”
- — Aristotle (c.320BC), De Anima (§:421a22)
Driesch elaborates on this as follows:
- “It has already been explained that the soul as an actuality, as an ‘entelechy’, organizes the body; here again, and in yet a higher sense, Aristotle calls the soul the ‘principle of all things’, to reach later his famous definition that the soul in the broadest sense is the ‘first actuality of a natural body, having in it the capacity of life, and of one possessed of organs’.”
- — Hans Driesch (1914), The History and Theory of Vitalism (pg. 18) 
Here, we see, Driesch, in short, attempting to salvage "soul theory", about which he spends some 40+ more pages on.
By the 1960s, Driesch tended to be grouped with Henri Bergson, Pierre Teilhard, and Michael Polanyi, as so-called "neovitalists", whose theories were attacked by those including: Charles Sherrington and Francis Crick. Jacques Monad (1970) classified Driesch's ideas as a type of “scientific vitalism”. Others, in recent years, have categorized his views as a type of “neo-teleology” (Cummins, 2002).
In 1886, Driesch began to study medicine under August Weismann at the University of Freiburg. In 1887, at the the University of Jena, he zoology under Ernst Haeckel and Oscar Hertwig and botany under Ernst Stahl. In 1888, at the University of Munich, he studied physics and chemistry. In 1889, he received his doctorate under Haeckel with his thesis "Tectonic Studies on Hydroid Polyps".
Quotes | On
The following are quotes on Driesch:
- “Driesch’s theory is ingenious, but I believe untenable. In fact it involves a reduction to the sphere of molecules of the old fallacy of Descartes. For to suspend the operation of the second law of thermodynamics would be precisely equivalent to an alteration, without the expenditure of energy, of the direction of motion of the particles of a material body. Under these conditions an object which had fallen to the ground might, by cooling itself, rise again into the air. Nothing could be more radically inconsistent with the fundamental principles of physical science, as now generally admitted, than this assumption or the theory which it is designed to support.”
- “Into the last generation there has been a recrudescence of vitalism—‘neo-vitalism’ it is now called—being obviously something that seems to be different from the Cartesian speculations about the sensitive soul. At its best this is seen in the ‘psychoids’ and ‘entelechies’ of Driesch and others, concepts which are applicable to living things only, and not to chemical and physical phenomena. At its worst modern vitalism is exhibited in the crude and even grotesque ‘spiritualism’ which has attained such a vogue with the less resolute thinkers of our own generation. This, then, is the modern impasse to which biology has come. Purely physico-chemical explanations of life are not satisfactory, and the immaterial and non-energetic agencies that are being invoked in their place have no interest for science, since they cannot be the objects of investigations.”
- — James Johnstone (1921), The Mechanism of Life in Relation to Modern Physical Theory (pg. 159, 193) 
- “As early as 1891, Driesch through some light on this enormous question. He employed the common sea urchin in his experiments. Like all other higher animals, the sea urchin begins its development with a series of cell divisions which are quite precise. First, the original fertilized egg divides into two cells, then four, then eight, then sixteen, and so on. Driesch discovered that if the individual cells are separated from one another by violent shaking in a four-cell stage, each of the resulting separated cells will go on to develop into a complete sea urchin. Later experiments demonstrated the same principle with other animals, including vertebrates . In fact, the occurrence of identical human Twins is ascribed to some form of intra uterine event that separates into two embryos the two cells that develop from the original fertilized egg.”
- — Dean Wooldridge (1968), Mechanical Man (pg. 31)
Quotes | By
The following are quotes by Driesch:
- “There ‘are’ no souls in the phenomenon called nature in space.”
- — Hans Driesch (1908), The Science and Philosophy of the Organism, Volume Two (pg. 86); cited by Jane Bennett (2010) in “A Vitalist Stopover” in New Materialisms (pg. 65) 
- “The analysis of the Aristotelian theory of life must therefore be one of the cornerstones of any historical works on biology.”
- — Hans Driesch (1914), The History and Theory of Vitalism (pg. 11) 
- “Ordered wholeness is not a ‘mechanism’, and wholeness can never result from genuine mechanism.”
- — Hans Driesch (1922), Reality Theory: a Metaphysical Attempt (pg. 79) 
- (a) Fisher, Len. (2004). Weight the Soul: the Evolution of Scientific Beliefs (ch. 7: What is Life?, pgs. 109-30). Weidenfeld & Nicholson.
(b) Hans Driesch – Eric Weisstein’s World of Scientific Biography.
- Wooldridge, Dean. (1968). Mechanical Man: the Physical Basis of Intelligent Life (pg. 31) . McGraw-Hill
- Driesch, Hans. (1904). Concepts of Nature and Judgments of Nature: Analytical Investigations into Pure and Empirical Natural Science (Naturbegriffe und Natururteile: analytische Untersuchungen zur Reinen und empirischen Naturwissenschaft) (Thermodynamik, 17+ pgs; Entropie, 18+ pgs; Energie, 84+ pgs; biologie, 34+ pgs). Publisher.
- Driesch, Hans. (1904). “Concepts of Nature and Judgments of Nature” ("Naturbegriffe und Natururteile") (abs), Nature, 71:270, Jan 19.
- Freyhofer, Horst. (1982). The Vitalism of Hans Driesch: the Success and Decline of a Scientific Theory (thermodynamics, 6+ pgs). Lang.
- Energetics debate – Hmolpedia 2020.
- (a) Mitchell, Robert. (2013). Experimental Life: Vitalism in Romantic Science and Literature. JHU Press.
(b) Monod, Jacques. (1970). Chance and Necessity: Essay on the Natural Philosophy of Modern Biology (Le Hasard et la Nécessité: Essai sur la philosophie naturelle de la biologie moderne) (Translator: Austryan Wainhouse) (pgs. 34-35). Vintage, 1971.
- Potential and actuality – Wikipedia.
- Energy landscapes – Hmolpedia 2020.
- Driesch, Hans. (1914). The History and Theory of Vitalism (translator: Charles Ogden) ("theory of life", pg. 11; soul, 43+ pgs). Publisher.
- Monod, Jacques. (1970). Chance and Necessity: Essay on the Natural Philosophy of Modern Biology (Le Hasard et la Nécessité: Essai sur la philosophie naturelle de la biologie moderne) (Translator: Austryan Wainhouse) (pgs. 34-35). Vintage, 1971.
- (a) Cummings, Robert. (2002). Functions: New Essays in the Philosophy of Psychology and Biology (editors: Andre Ariew, Robert Cummins, and Mark Perlman) (pgs. 157-72). Oxford.
(b) Cummins, Robert. (2009). (2009). Philosophy of Biology: an Anthology (editors: Alex Rosenberg, Robert Arp) (§12: Neo-Teleology, pgs. 164-74). Wiley.
- Henderson, Lawrence. (1917). The Order of Nature (pg. 91). Harvard University Press.
- Johnstone, James. (1921). The Mechanism of Life in Relation to Modern Physical Theory (pg. 159, 193). Longmans, Green & Co.
- Bennett, Jane. (2010). “A Vitalist Stopover: on the Way to New Materialism”, in: New Materialisms: Ontology, Agency, and Politics (editors: Diana Coole and Samantha Frost) (§:47-69, quote, pg. 65). Duke.
- Driesch, Hans. (1922). Reality Theory: a metaphysical Attempt (Wirklichkeitslehre. Ein metaphysischer Versuch.) (2nd edition) (pg. 79). Publisher.
- Driesch, Hans. (1908). The Science and Philosophy of the Organism. Gifford Lectures, 1907-1908. Publisher.
- Driesch, Hans. (1914). The Problem of Individuality. Publisher.
- Driesch, Hans. (1924). The Possibility of Metaphysics. Four Lectures, University of London, Mar.
- Bonner, John. (2017). “On Edwin Conklin vs Hans Driesch” (YT), Web of Stories, Jul 3.
- Hans Driesch – Hmolpedia 2020.