We all think we believe what we believe for good reasons – especially philosophers. However, as figures such as Nietzsche, William James and Iris Murdoch have suggested, what we believe may be influenced far more by our psychology and life experiences, rather than by logic and reason, writes David Bryce Yaden and Derek Anderson.

How do philosophers come to endorse one view over another? One might imagine an impartial analysis of the merits of various arguments. Indeed, we don’t doubt that this accounts for the majority of the process. But what other influences­­––perhaps more psychological––should we consider? That is the question that we explored in our new paper, “The Psychology of Philosophy.” [1]

One potential influence on a given philosopher’s views may be their personality or other psychological traits. Does a philosopher’s disposition relate to complicated philosophical views, such as whether free will exists, whether one endorses deontological or consequentialist ethical views, or whether morality and aesthetics are objective or subjective? These questions are not new.

In Beyond Good and Evil, in a section called “The Prejudices of Philosophers” Nietzsche writes:

"They all pose as though their real opinions had been discovered and attained through the self-evolving of a cold, pure, divinely indifferent dialectic (in contrast to all sorts of mystics, who, fairer and foolisher, talk of "inspiration"), whereas, in fact, a prejudiced proposition, idea, or "suggestion," which is generally their heart's desire abstracted and refined, is defended by them with arguments sought out after the event…It has gradually become clear to me what every great philosophy up till now has consisted of--namely, the confession of its originator, and a species of involuntary and unconscious auto-biography”

Does a philosopher’s disposition relate to complicated philosophical views?

In Pragmatism, William James writes:

“The history of philosophy is to a great extent that of a certain clash of human temperaments. Undignified as such a treatment may seem to some of my colleagues, I shall have to take account of this clash and explain a good many of the divergencies of philosophers by it. Of whatever temperament a professional philosopher is, he tries when philosophizing to sink the fact of his temperament. Temperament is no conventionally recognized reason, so he urges impersonal reasons only for his conclusions. Yet his temperament really gives him a stronger bias than any of his more strictly objective premises.”

In The Sovereignty of Good, Iris Murdoch writes:

“To do philosophy is to explore one’s own temperament and yet at the same time to discover the truth. It seems to me that there is a void in present-day moral philosophy…A working philosophical psychology is needed...”

One might wonder whether it is significant that each of these philosophers who drew special attention to the role of temperament in philosophy also had substantial interdisciplinary expertise or training. Before writing now classic works of philosophy, Nietzsche was a professor of philology at the University of Basel with a focus on historical texts from Greece. James had a medical degree and was a founder of empirical psychology before becoming a professor of philosophy at Harvard. Murdoch taught philosophy at Oxford and was an acclaimed novelist.

The theme of these speculations from these interdisciplinary philosophers is that our real reasons for believing are not what we take them to be. Many philosophers act as if they are simply being rational, following the evidence and arguments where they lead with the disinterested clarity of an objective investigator. But for Nietzsche, James, and Murdoch, as well as many others to be sure, this belief in our own objective rationality is suspect. If our temperament or “our heart’s desire” is guiding our philosophical worldview, then our commitment to pure rationality is partly a refusal to acknowledge our real reasons for believing.

If our temperament or “our heart’s desire” is guiding our philosophical worldview, then our commitment to pure rationality is partly a refusal to acknowledge our real reasons for believing.

Our own humble contribution to this topic emerged out of an interdisciplinary conversation among friends that stretches over many years, beginning in our undergrad years. We, a psychologist (David Yaden) and a philosopher (Derek Anderson), began discussing the reasons why people in our philosophy and cognitive science clubs seem so quickly attracted to one view over another––even after very little exposure to the relevant arguments or evidence. Of course, there are important sociological issues to consider (i.e. what professor you happened to have or book you recently read), but we wondered whether there could also be psychological reasons to account for the attraction one feels to a particular view.

It was years before we were able to return to this question. We both first needed to get our doctorates in psychology and philosophy. But over this period of time, two important things happened in the field of philosophy. The first was that a new branch of philosophy was formed, called Experimental Philosophy (“x-phi” for short). This field uses methods from psychology to address philosophical questions. The idea is to get up off the proverbial armchair and to collect data – the primary symbol of x-phi according to Josh Knobe is a burning armchair [2]. X-phi focuses on peoples’ intuitions on various thought experiments, to see whether or not they differ across cultures or between professional philosophers and non-philosophers. Here is an example of a common thought experiment (this one was originally proposed by Bertrand Russell and later Edmund Gettier created closely related thought experiments which upended the study of epistemology for forty years):

Imagine a person who looks at an analog clock. The hands of the clock display the time 3:00pm. On the basis of this, the person comes to believe it is 3:00pm. Since looking at a clock is a good source of justification for knowing the time, the person seems to be justified in their belief. Let’s also assume that it really is 3:00pm. But unbeknownst to the person, the clock is actually broken. It always points to 3:00pm. It is only a strange accident that the person happened to look at precisely the right time to form a true belief.

Does this person know that it is 3:00pm? Many philosophers have judged that, intuitively, the person does not know. If this intuition is correct, then knowledge must require more than a true justified belief (which is the traditional analysis of knowledge). But does everyone share this intuition, or is there variability in people’s judgments? If there is variability, what explains this? These are empirical questions which x-phi has been concerned to answer.