Critical Thinking: Guidelines from Thomas Aquinas

Thomas Aquinas as a philosopher and master of critical thinking must be the best-kept secret in nursing. The only exception seems to be The Careful Nursing Philosophy and Professional Practice Model. His neo-Aristotelian philosophy of the human person works beautifully for nursing. 

For example, most agree that the principle of holism is of central importance in nursing. But, many are unaware that the term was coined in the 1920s by Jan Smuts, a South African statesman, philosopher and military leader. In the wake of World War I, he sought to develop in a doctrine of the unity of life that would lead to a more harmonious and spiritually-oriented world, which he first published in 1926 in Holism and Evolution.

In his second edition, Smuts (1927) notes that a reviewer of his first edition had made him aware of the "striking similarity" between his philosophy of holism and Aquinas's neo-Aristotelian philosophy of the unitary nature of life. He realised that his idea of holism, or the unity of life, had been widely examined and discussed by philosophers for centuries. But, more about this another time: for now, let us take a look at how Aquinas could help us to be really good critical thinkers. 


At the early universities of the 13th century, when Aquinas was a Master at the University of Paris, the standard method of critical thinking and knowledge development was disputation. This is a method of debating that requires opponents in a debate to present not only their arguments in support of their point of view, but also arguments which opposed their point of view. In addition, they must accept or refute the opposing arguments point by point and everything must be supported by references from the literature. This method was also used in written presentations. If you read Aquinas, you will notice right away that he wrote in this style.

Advantages of critical thinking as disputation

With the completion of a disputation the writer or presenter aims to have rejected convincingly all possible arguments against the validity of the original assumption so that it can be accepted with probable confidence. If it cannot be rejected convincingly, it's back to re-thinking the question. Notice that this approach, developed over 800 years ago, is not too different from our contemporary quantitative approach to knowledge development. That is, we have an idea that we formulate as a research problem and pose it as a research question. Then we state the research hypothesis but we test the null hypothesis. Only when we can reject the null hypothesis can we accept the research hypothesis with some probable confidence.

Disputation has a number of advantages in helping us develop the habit of thinking critically. It builds on what is already known about a topic according to the literature. It is designed to control for personal bias, or thinking only what we want to think. It can be adapted easily as a basis for writing a literature review for a term paper or thesis or for structuring a seminar or debate. And, of course, it can be used by nurses in clinical practice and management to tease out the pros and cons of nursing interventions and other approaches to patient care. An example of a disputation is shown in the following Table, using a Careful Nursing assumption as the topic. 


A Disputation Guided by the Approach of Thomas Aquinas

Method Example Using a Careful Nursing Assumption
Formulate a reasoned assumption The philosophy of Aquinas is an appropriate philosophical foundation for Careful Nursing.
State the assumption as a question Is the philosophy of Aquinas an appropriate philosophical foundation for Careful Nursing?
Propose a negative response to the question It seems that the philosophy of Aquinas is not an appropriate philosophical foundation for Careful Nursing.
State 3–5 objections in support of the negative response to the question Objection 1: Aquinas was a Christian theologian as well as a philosopher and almost everything he wrote was shaped by his theology (Floyd, 2010). Aquinas's religious views compromised his ability to truly engage in philosophical debate and his philosophy amounts to little more than special pleading for his own personal point of view (Russell (1945/1972). Therefore, the philosophy of Aquinas is not an appropriate philosophical foundation for Careful Nursing. 

Objection 2: Scholarship based on the philosophy of 13th century thinkers is unreliable because only a small number of their texts have been cataloged and few have been translated from Latin into modern languages. Specialized knowledge of the historical period is necessary for their valid interpretation for contemporary application (MacDonald & Kretzmann, 1998). Therefore, the philosophy of Aquinas is not an appropriate philosophical foundation for Careful Nursing.

Objection 3: Contemporary nursing knowledge development is a scientific endeavor and models and theories of nursing are founded on advanced, post-Enlightenment, thinking (Fawcett & DeSanto-Madeya, 2012). A comprehensive presentation of philosophies relevant to nursing knowledge development (Rogers 2005) includes ancient philosophers up to Aristotle and then continues directly to Descartes, indicating that philosophers of the 1,700-year intervening period are not relevant to nursing. Therefore, the philosophy of Aquinas is not an appropriate philosophical foundation for Careful Nursing.

Objection 4: "Real nurses nursing real patients are busy and tired, and therefore unable to engage in elaborate conceptual exercises throughout their working day" (Newton, 1991, p. 193). Thus, there is no point in encouraging nurses in practice to think philosophically about the nature of their patients, themselves, and their practice. Textbooks on nursing models and theories address philosophy of science but pay minimal attention to philosophy of nursing per se (McKenna et al, 2014). Therefore no philosophy, including that of Aquinas, is an appropriate foundation for Careful Nursing.

Make a statement contrary to the objections (a positive response to the question) On the contrary: Philosophy from the 13th century period offers rich resources for the development of contemporary philosophy (Koterski, 2009). A widely recognized present-day philosopher Alasdair MacIntyre (2007, 2009) reasons that the ideas and arguments developed by Aquinas are of vital importance in understanding the nature of human beings and the ethics of the social, political and economic activities which they create; all of which are of central importance to nursing's concern with human health and flourishing.



Table 1 Continued

Format Disputation
State your own reasoned response to the question as a concise discussion I respond that: According to the etymological origin of the term nurse (Connell, 1983) and the documented public service provided by nurses since the 1st century C.E. (Meehan, 2012b), the purpose of nursing is the nurturance and protection of sick, injured and vulnerable human beings and fostering of their health. The profession's claim to view the human being as a unitary (holistic), spiritual being is well established in contemporary professional literature (Alligood & Marriner-Tomey, 2010). But, comprehensive philosophical foundations that support these claims is generally absent (Sarter, 1988), or limited to so-called world views constructed from concepts of contemporary science and philosophies of science (Fawcett & DeSanto-Madeya, 2012).

This situation exists because universities tend to be dominated by Cartesian, scientific thinking to the detriment of human sciences and exploration of pre-Enlightenment philosophical thought (Scruton 2004). Universities also generally avoid exploration of the spiritual dimension of human life from any particular Western philosophical perspective (MacIntyre, 2009; Scruton, 2015).

Thus, contemporary nurses have tended to be cut adrift intellectually from philosophies deeply consistent with descriptions and explanations of nursing. Likewise, they have tended to lose their professional historical consciousness and until recently their spiritual consciousness. The philosophy of Aquinas addresses ideas of great importance to nursing in depth and detail, providing an abundant source of propositions and theories for the nursing profession to drawn on.

Reply to each objection explaining why it is incorrect or inadequate.  Reply to objection 1: Although Aquinas was a Christian theologian as well as a philosopher, his thinking and conclusions were developed strictly according to objective, reasoned argument. Much of his writing is based on the work of Aristotle and regarded as philosophical. Formerly, theology and philosophy were so interrelated that even some of Aristotle's philosophical writing is considered theological (McInerny & O'Callaghan, 2015). Aquinas was meticulous in distinguishing between his thinking as a theologian and his thinking as a philosopher (Kenny, 2002).

Reply to objection 2: Scholarship from the 13th century is voluminous because universities were just beginning to develop at that time. While much of this scholarship is available only to specialists, the writings of Aquinas are an exception. Almost all his extensive writings have been translated from Latin into modern languages by different translators. His writings and the translations are widely verified, commented on and discussed in relation to his historical period (Thomas Instituutte Utrecht , 2002).

Reply to objection 3: Despite bias in the nursing profession for scientific approaches to knowledge development by theorists (Fawcett & DeSanto-Madeya, 2012) and philosophers (Rogers, 2005), nurses in practice seek humane approaches to understanding the unitary, spiritual nature of patients (McGee, 2000). Watson's caring science (Sitzman & Watson, 2014) responds to this need but explains the spiritual and holism in nursing by drawing on popular Eastern philosophies such as Buddhism and by using Western pre-Enlightenment terms lifted out of their original context and redefined, for example caritas.

Reply to objection 4: A hallmark of professional practice is to be intellectually engaged. Any claim by nurses that they are too busy and too tired to think about what they are doing is incompatible with professional responsibility. Nurse–philosophers are becoming more concerned with development of philosophical approaches to practice as they think they will contribute to understanding practice beyond concerns with technical expertise and measurable outcomes (Holt, 2013).

This Table is excerpted from Careful Nursing News, 7(2) 2015, 13-15., available in the Publications section of this webpage: see pp, 17-19 for references cited in the Table. 

Aquinas wrote extensively about the human intellect, for example, (1265-1274/1948, Part I, Questions 12, 75-78, 81, 95; Part I-II, Questions 9, 17, 23, 25, 26). He wrote in a straightforward style for the ordinary educated people of his time. However, beginning contemporary readers usually need guidance in understanding his metaphysical terms and in becoming accustomed to his writing structure. But, don't be put off by this. There is too much at stake. The pay-off for nursing knowledge development is great.

To begin with, Aquinas' thought on the human intellect can be explored most easily in secondary sources, for example, Aquinas on Mind (Kenny, 2002) or in more accurate detail in "Philosophy of Mind and Human Nature" (Pasnau, 2012). In addition, Boland (2014) applies Aquinas's ideas to contemporary education.

I highly recommend getting to know Thomas Aquinas and his method of disputation. Do give it a go and see what you think.


Aquinas, T. (1265-1274/1948). Summa Theologica (Fathers of the English Dominican Provence trans.). New York: Benziger Brothers.

Boland, V. (2014). St Thomas Aquinas. London: Bloomsbury Academic.

Kenny, A. (2002). Aquinas on Mind. New York: Routeledge.

Pasnau, R. (2012) Philosophy of mind and human nature. In B. Davies & E. Stump (Eds.), The Oxford Handbook of Aquinas (348-370). Oxford: Oxford University Press.

Smuts, J. C. Holism and Evolution. London: Macmillan & Co.; 1927, p.106. 

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