Does the CRT track what it is claimed to track?

The CRT has been seen as an indicator of rationality (Stanovich 2011; Toplak et al. 2011, p. 1283), reflectivity (Livengood et al. 2010; Szaszi et al. 2017, p. 208) and analyticity (Sytsma 2016; Stahl and van Prooijenb 2018). These are all traits that have prima facie plausibility as part of the ideal philosophical personality.Footnote 12 Yet it is far from clear whether we can straightforwardly associate CRT performance with these traits. Two alternative possibilities for what the CRT tracks stand out in the literature: numeracy and/or confidence.

Numeracy

Numeracy is one’s ability to store, represent and process mathematical operations (Peters, 2012). It has been widely discussed how difficult it is to disentangle cognitive reflection from numeracy (Thomson and Oppenheimer 2016, p. 101). All three test questions involve numbers, lending prima facie plausibility to the suggestion that the CRT tracks numeracy. There also exists a large body of research suggesting that the CRT measures both cognitive reflection and numeracy.Footnote 13

In Frederick’s original study, only one other cognitive test showed a gender difference—the SAT maths scores (Frederick 2005, p. 37). Frederick comments that “men generally score higher than women on math tests” and he cites various studies from the 80s and 90s to support this claim. As I will discuss below, there is now strong counter-evidence to this. However, some studies do continue to point towards gender differences in maths ability, particularly as age of participants and complexity of the test increases (e.g. Ganley and Vasilyevam 2014; Lindberg et al. 2010, p. 1132; Benbow et al. 2000). Primi et al. (2018, pp. 261–262) suggest that the strongest available evidence for gender differences in maths performance comes from the Programme for International Student Assessment (PISA), which assesses the competencies of 15 year old students from 65 countries in various subjects, including Mathematics. On average across OECD countries, boys outperform girls in Mathematics by eight score points. The difference is most notable amongst the highest achieving students: the highest-scoring 10% of boys score 16 points higher than the best-performing 10% of girls (OECD 2016, p. 196).Footnote 14

If there is a numeracy gender gap, it seems plausible that this might be explanatory for the CRT gender gap. This explanation is supported by research by Thomson and Oppenheimer (2016). They piloted the ‘CRT-2’, a test designed to measure cognitive reflection whilst avoiding conflation with numeracy. The CRT-2 uses “trick questions” that “do not require a high degree of mathematical sophistication” (2016, p. 101).Footnote 15 200 participants were tested on both the CRT and the CRT-2 and it was found that the gender gap significantly lessened on the CRT-2. Whilst men (M = 65.9% correct) significantly outperformed women (M = 36.0% correct) on the original CRT (p < 0.001), men (M = 60.5% correct) and women (M = 53.3% correct) were not reliably different on the CRT-2 (p > 0.05) (Thomson and Oppenheimer 2011, pp. 106–107). This finding is consistent with differences in numeracy being a cause of the gender gap on the original CRT.

This explanation is further supported by a recent study by Primi et al. (2018), which found that the direct effect of gender was no longer statistically significant once the variables of mathematical reasoning and maths anxiety were taken into account. Additionally, Szaszi et al. (2017) suggest that we simply cannot separate numeracy from reflectivity on the CRT, since good numeracy is likely to deliver you the right intuitions from the start. Indeed, it is notable from reading their examples of participants’ vocalised thought processes that ‘Correct Answer’ respondents often recognised that there was an equation that needs solving in the bat and ball question (Szaszi et al. 2017, p. 218).

The research at present does not, however, lead us to a position where we can say that gender differences in the CRT can be entirely explained via gender differences in numeracy. Firstly, we should note that Thomson and Oppenheimer’s CRT-2 has not gained popularity, nor is it agreed whether it tests the cognitive skill that behavioural economists and psychologists have become so interested in. As Primi et al. (2018, p. 274) point out, the correlations between the CRT-2 and various measures of rational thinking and decision-making skills were generally weaker than the correlations between these measures and the original CRT. Secondly, other studies, including Frederick’s original study, claim to have controlled for numeracy and yet found that a significant gender gap remains (Frederick 2005, p. 37; Agnew 2017, p. 12). Thirdly, it is far from clear to what extent there is, in fact, a gender numeracy gap. In their meta-analysis of 242 studies published between 1990 and 2007, representing the testing of 1286,350 people, Lindberg et al. (2010, p. 1131) conclude that “there is no longer a gender difference in mathematics performance”. This is consistent with Hyde et al.’s (2008) study, which (using data from over seven million students) found no evidence of gender differences on US state math tests among students between Grade 2 and Grade 11. Where gender differences in favour of males are seen (for example, in complex problem-solving at high school level), these differences appear to be attributable to multiple possible environmental explanations (for example, that parents and teachers give higher ability estimates to boys than girls, and that patterns of interest are affected by cultural influences) (Lindberg et al. 2010, p. 1132). This latter possibility would also help explain why gender differences in maths differ across countries, as well as the fact that these differences correlate with gender inequality measures for those countries (Else-Quest et al. 2010; Guiso et al. 2008; Penner 2008).

Nevertheless, a consensus does seem to have developed that numeracy is at least one component in performance on the CRT (Thomson and Oppenheimer 2016, p. 101; Szaszi et al. 2017, p. 207; Primi et al. 2018). What is the significance of this for explaining the gender gap in Philosophy?

It might be that the CRT tracks numeracy, and numeracy is required for success in Philosophy.Footnote 16 This fits with the high regard that philosophers have historically held for mathematics. It may be that maths skills are closely related to philosophical skills, particularly those required for Logic, which is often a compulsory component of Philosophy programmes. Evidence suggests that studying advanced mathematics develops some aspects of conditional reasoning, including the ability to reject invalid inferences (Inglis and Attridge 2016, p. 130), and so there is good reason to think that maths skills and logical skills are linked. Some have even argued that mathematical competence is crucial to good Philosophy. Boghossian and Lindsay (2016) declare that “If you want to be a good philosopher, don’t rely on intuition or comfort. Study maths and science.” Their reason is that “Philosophers who can think like mathematicians are better at clear thinking, and thus philosophy.”

However, evidence supporting this view seems rather sparse. As Thompson (2017, p. 3) says, the extent to which maths skills are required for success in Philosophy is not yet clear. Moreover, evidence of good numeracy is rarely, if ever, an entry requirement for university Philosophy programmes.Footnote 17

Given the research at present, it is unclear (i) whether women are worse at numeracy, (ii) the extent to which the CRT measures numeracy and (iii) whether numeracy is required for success in Philosophy. We therefore cannot adequately justify the conclusion that women’s tendency towards a low CRT score represents low numeracy, which contributes to their low participation in Philosophy.

Confidence

Some have praised the CRT for being a “performance measure rather than a self-report measure” (Toplak et al. 2011, p. 1275), but this neglects the important effect that self-perception of one’s abilities can have on performance. It may be that the CRT tracks confidence in numerical abilities rather than (or in addition to) actual cognitive abilities. Zhang et al. (2016, p. 427) found that when differences in quantitative self-efficacy (perceived fluency with numerical information) are controlled for, gender differences on the CRT disappear. They conclude that “men perform better on the CRT because they are more confident in their quantitative abilities” (2016, p. 427).

This is consistent with research on maths anxiety and gender differences, which has found that females suffer more from maths anxiety than males (Else-Quest et al. 2010; Devine et al. 2012). Ganley and Vasilyevam (2014)’s research suggests that female’s heightened worry on maths tests utilizes their visuospatial working memory resources, leading to poorer performance. This would fit with Szaszi et al.’s (2017) suggestion (discussed in Sect. 2.1) that those answering the CRT questions incorrectly may be failing to bring to mind the strategic rules needed to solve the questions.

It also fits with the wider picture given by research on confidence, which has suggested that women tend to have lower levels of self-confidence than men.Footnote 18 We might hypothesise that pursuing Philosophy to higher levels requires a degree of confidence in one’s abilities that women are less likely to possess. There is at least some prima facie reason to think that confidence contributes to successful progression within the field. For example, the level of confidence with which you deliver your question or paper, or the conviction with which you profess your conclusion, is likely to affect the way that it is received by others (see Schwitzgebel (2010) on the potential effects of “being good at seeming smart”). Additionally, effectively ‘batting away’ opponents requires not just intellect, but an element of performance (Larvor 2015). As Justin Weinberg (2015) comments, most graduate students in Philosophy are advised to “project confidence”. Perhaps women’s poorer performance on the CRT tracks their high anxiety and low confidence, and these traits affect their levels of participation and performance in Philosophy.

However, a concern with this line of reasoning is that Zhang et al.’s study, like many others, does not account for the possibility that people’s beliefs about ability are accurate (Lemoine 2017; Jussim 2012). That is, the self-report measure of quantitative self-efficacy may track numeracy, because the people that lack confidence in their quantitative abilities do so because they are, as a matter of fact, less competent at numeracy. This is consistent with research by Primi et al. (2018, p. 273), which found a direct link between maths anxiety and cognitive reflection, but found that the effect of maths anxiety on cognitive reflection was partially mediated by mathematical reasoning.

If quantitative self-efficacy is strongly linked with actual mathematical ability, then we are back to our unanswered question of whether numeracy is relevant to success in Philosophy.

Implications

The research discussed in this section does not point to clear conclusions about what the CRT tracks. Nor is it clear what the relevance to explaining the gender gap in Philosophy would be. However, it does suggest that we should, at the least, be sceptical about a straightforward equating of CRT score with rationality, reflectivity or analyticity. It therefore attacks a version of IPP that suggests that it is a lack of these particular traits that holds women back in Philosophy.

The discussion so far has not attempted to deny that there may be traits that women tend to lack which might help explain the gender gap in Philosophy. Rather, it has explored the possibility that the CRT tracks numeracy or confidence. The absence of relevant empirical research on the roles that numeracy and confidence play in Philosophy means that we are unable to say to what extent these attributes are currently valued in Philosophy and whether they contribute to successful progression in the field as it stands. There is, however, some anecdotal evidence suggesting that confidence might contribute to successful progression in the field, lending at least some, limited support to IPPD.

Is the trait tracked by the CRT something we should value in philosophers?

There is clearly a question mark over what the CRT tracks. But whatever it tracks, this is something that women tend to have less of than men and philosophers tend to have in abundance. So, we can raise a second question asking why we should think that the CRT tracks something that we should value in philosophers. That is, even if IPPD is true, why should we think that IPPN is true?

The idea that the CRT tracks something we should value in philosophers seems to be assumed by Livengood et al. When talking of the ‘philosophical personality’, the authors say that they seek only to describe “who philosophers are” (2010, p. 314). But at points they slip from this descriptive exercise by implicitly adopting the normative assumption that they have identified a philosophical virtue. For example, they imply that what the CRT tracks is part of the expertise of philosophers (2010, pp. 319, 320).

But who philosophers are and who philosophers should be are different questions. The fact that some norm exists amongst philosophers which correlates with their good performance on CRTs does not, in itself, tell us that this trait is an asset to philosophising. Imagine that there was evidence suggesting that philosophers are more likely to exhibit social awkwardness than non-philosophers. It would be wrong to conclude from this research that social awkwardness is part of the ideal philosophical personality (even in the sense of IPPD, for this trait might appear accidentally, rather than being (consciously or unconsciously) selected for). Rather, this trait is irrelevant (or even detrimental) to good philosophising.

Similarly, we might generalise from the finding about CRT tracking quantitative self-efficacy to say that philosophers have a tendency to be more confident about their cognitive abilities. But again, this attribute does not necessarily make for better philosophising. The philosophers discussed in the previous section who have offered anecdotal support for the role of confidence in Philosophy have tended to see this as a flaw in currently philosophical practice—a mark of a deep methodological problem with the way that Philosophy currently operates (Larvor 2015). Indeed, one might even think that those with lower confidence actually make for better philosophers, because they may be more open to counter-arguments. When evaluating IPPN, the salient question in assessing the relevance of the CRT should be whether whatever it tracks is an epistemologically relevant trait, one that we should value as conducive to the pursuit of knowledge (or whatever we see as the aim of Philosophy).

This idea that certain traits might be dominant in Philosophy without necessarily being conducive to good philosophising becomes more plausible when we consider the flaws in the supposedly meritocratic system used to select philosophers (onto courses, and into posts). It has been well-discussed that meritocratic selection may be subject to biases at the level of deciding whether a candidate fulfils certain criteria.Footnote 19 But it may also be that there is bias present in deciding what these criteria are.Footnote 20 The ‘success criteria’ of what it is to be a good philosopher are (at least partially) decided by those already successful in the discipline, so that the norms and values of these individuals are reproduced in those selected, in a kind of feedback loop (Jenkins 2013). For example, Haslanger (2008, p. 217) and others have expressed concern over the dominance of a hyper-rational norm in Philosophy, which is often taken to represent the high-end of the discipline, but which may not necessarily contribute towards good philosophising.

So, it may be that the CRT tracks trait T, and those possessing T are (intentionally or unintentionally) more likely to be recruited to Philosophy. But this does not, in itself, tell us that T is important for good philosophising. This ‘irrelevant trait hypothesis’ resists the move from IPPD to IPPN, as it suggests that although the trait(s) tracked by the CRT may be part of the philosophical personality, this does not mean that they are part of the ideal philosophical personality. It suggests that the CRT tracks a trait that is not relevant to good philosophising, but either (1) just so happens to be well-represented in philosophers, despite not being selected for (as in the social awkwardness example) or (2) is unconsciously or consciously selected for because it is mistakenly thought to be part of the ideal philosophical personality (as in the confidence and hyper-rationality examples). If this were the case, then we certainly should not settle for the Inaction Conclusion. Rather, we should seek changes to the status quo in the discipline, such as re-evaluation of the criteria used when assessing applicants for Philosophy jobs.

This response has flagged that there is an open question as to whether we should be valuing whatever it is that the CRT tracks. But there are difficulties with pursuing this ‘irrelevant trait hypothesis’. Though there may be scope for debate over the purposes and methodology of the discipline, there is also wide agreement that Philosophy aims at the truth. The person who does badly in the CRT gets the wrong answers, and philosophers are after right answers. Moreover, as has been discussed, it seems plausible to say that it is part of good philosophising to engage in careful reflection over one’s intuitions, and to be especially immune to biases of judgement. We therefore might not want to press too hard with the idea that there is nothing of value in what is tested by the CRT.

How important is this trait to good philosophising?

We might concede that the CRT tracks something of value, but argue that it is only one small part of the cognitive skills that contribute to good philosophising.

Imagine a test used to assess physical fitness for the military that has press-ups as the key element. Since women tend to have lower levels of arm strength than men, they might find it harder to pass this test. But it would be wrong to conclude that the women who fail this test are ‘physically unfit’. Arm strength is just one small part of physical fitness; core strength and endurance also have an important role. In the same way, we might allow that the CRT tracks one aspect of rationality that women tend to have less of than men, but without drawing any conclusions about overall levels of rationality.

In our military fitness example, the important practical question is whether a certain level of arm strength is required for success in the military. Analogously, the salient question for us is whether the aspect of rationality potentially tracked by the CRT is an essential element in good philosophising. There seem to be good reasons to think that it is not, and rather, that the type of reflectivity tracked by the CRT is only one, fairly minor skill utilised by philosophers. It might make for a good start to one’s philosophical project to begin with sound thoughts that have already been subject to some System 2 scrutiny, but it seems that the bulk of philosophical work comes later.

Consider how Livengood et al. set the scene for explaining the aspect of the philosophical personality that they are interested in:

An intuition is a spontaneous intellectual sensation: p seems to be true without being consciously inferred. In considering the first question of the CRT, for example, it intuitively seems that the answer must be 10 cents. Similarly, in the Gettier case, it intuitively seems that the agent does not have any knowledge… (Livengood et al. 2010, p. 318)

There seems something odd about this analogy. In the CRT, intuition delivers the wrong answer, and getting the right answer requires overriding intuition (rather than making use of it). In the Gettier case, we have an intuition which then becomes the subject of further philosophical exploration. By presenting thought experiments invoking certain intuitions, Gettier’s (1963) paper far from closed the question of whether knowledge is justified true belief. Rather, it was the starting point of an ongoing philosophical project. Further philosophical work has consisted in: (i) suggesting additional conditions that might be added in order to avoid Gettier cases, such as the ‘no false lemmas condition’ (e.g. Armstrong 1973, p. 152; Clark 1963), (ii) engaging in further thought experiments to question the conditions for knowledge (e.g. Goldman’s (1976) ‘fake barn’ cases), (iii) making distinctions within ‘justification’ and exploring what it takes for a belief to be justified (e.g. Feldman and Conee 2001), and (iv) suggesting alternative accounts of what constitutes knowledge, such as reliabilism (e.g. Nozick 1981). If it makes sense to talk of ‘getting the right answer’ to a Gettier case, arriving at this ‘right answer’ when the case is first presented seems to be only a small and insignificant part of the process, and it is not clear to what extent getting the answer wrong at the start would be damaging to the long-term philosophical project.Footnote 21 Philosophers have far more than the few seconds or minutes spent on the CRT questions to properly evaluate Gettier cases and come to a judgement on what knowledge really consists in. Thus although there might be something in the reflectivity that is tested in the CRT, it seems like there is another, broader type of reflectivity that is of more value and importance to the long-term philosophical project—perhaps one involving an indefatigable pursuit of answers, even where these are particularly hard to find.Footnote 22

The above discussion has given just one reason to question the relative value of the trait(s) tracked by the CRT compared to other traits that are potentially part of the ideal philosophical personality. Given the precise nature of the CRT questions, set against the range of virtues and skills that we might plausibly postulate as part of the ideal philosophical personality, my view is that we probably need not hang too much on whatever the CRT tracks. Not all philosophers perform well on the CRT and so it is, at the least, possible to successfully progress in the field whilst lacking this particular skill. And even if the trait that the CRT tracks contributes to good philosophising, it is far from clear that this trait is essential to good philosophising and therefore to the ideal philosophical personality in the sense of IPPN.

Moreover, it could be that there is a correlation between possessing above-average levels of analyticity (or whatever we suppose it is that the CRT tracks) and lacking other skills that are valued amongst philosophers, such as creativity. This is purely speculative, but it is conceivable that a high CRT score comes at the expense of other virtues that we need more of in Philosophy.Footnote 23 Kahneman says that “absence of bias is not always what matters most” (2011, p. 192), and this surely applies to Philosophy. It could be that relief from the constraints of analyticity allows for more creative thinking, increasing the likelihood of hitting upon unusual, divergent ideas. If this were true, low CRT score should not be viewed as indicative of a poor philosopher.

Reflecting back on the military fitness example may be helpful here. Let us say that (1) men have more arm strength than women, (2) military personnel have more arm strength than those outside the military, (3) there are more men than women in the military and (4) there is a good prima facie case for thinking that arm strength contributes to doing your military service well. This state of affairs is perfectly consistent with there being other attributes that contribute to success in the military that women have more of than men (for example, endurance or emotional literacy). If this were the case, in addition to checking that entry tests for the military are not overly-focused on arm strength, it would also be important to look at how other factors such as discrimination and unconscious bias might be contributing to the under-representation of women.

Applying the same reasoning to our case: Even if it is true that the trait T tracked by the CRT is currently valued amongst philosophers (i.e. there is some truth to IPPD), and even if possessing T does, as a matter of fact, make some contribution to good philosophising (i.e. there is some truth to IPPN), it would still be wrong to think that the empirical research entirely explains the gender gap in Philosophy. Since T is one amongst many possible philosophical virtues and skills, women tending to exhibit less of T should not be having such a dramatic effect as to produce the wide gender gap we see in Philosophy. If that is not the case, and in fact it is a significant factor, because possessing trait T is wrongly being prioritised as an important selection criterion, we might speculate that this is detrimental to the discipline of Philosophy, since prioritisation of T might come at the expense of other valuable philosophical virtues and skills. Regardless of the truth of this last hypothesis, the Inaction Conclusion would be unjustified. Rather, as in the military case, we should turn a critical eye to entry criteria, as well as onto whether there are other obstacles to women’s participation such as discrimination and unconscious bias.

How should we understand the causal story?

Lastly, and importantly, we should note that the direction of causation has not been established between CRT scores and philosophical training. We cannot say whether it is philosophical training that leads to the increased CRT score amongst philosophers, or whether possessing the trait(s) tracked by the CRT to a high degree leads people to undergo more philosophical training.Footnote 24

At least three possibilities explain the current data. Firstly, it may be that people with higher CRT score are more likely to take up further philosophical training (Fig. 1).Footnote 25 Since women tend to have lower CRT score, fewer women continue in Philosophy.

Secondly, it might be that the two facts are independent and we should draw no conclusions from the gender gap in CRT score and the increased CRT score of philosophers (Fig. 2).

However, given all that has been said so far, it seems unlikely that these facts are entirely independent. Imagining our social awkwardness example to be true, we would probably want to posit at least some causal relation between the phenomena. For example, we might hypothesise that you need to be clever to be a philosopher and being clever makes it harder to talk to other people. Analogously, there is likely to be some causal story that can be told between the gender gap in CRT score and the gender gap in Philosophy.

Thirdly, it could be that practising Philosophy brings up your CRT score, but fewer women are continuing with Philosophy (for reasons unrelated to CRT score) (Fig. 3). Women may be put off staying in Philosophy by contingent features of the discipline in its present state, features that are amenable to change by the actions of university faculties.Footnote 26 If this were the case, it would be an injustice that we should actively seek to rectify, for women would be missing out on opportunities to develop their capacities in whatever it is that the CRT tracks.

This third explanation denies both IPPD and IPPN, since it denies that the gender gap in the CRT is explanatory for the gender gap in Philosophy. It says that although the CRT may track a trait that is part of the philosophical personality, it is the study of Philosophy that nurtures this trait, and so we must look elsewhere for explanations of why women tend not to continue studying Philosophy beyond their tendency to have a lower CRT score.

However, given the small number of participants in Philosophy, clearly the gender gap in Philosophy cannot account for the gender gap in CRT score on its own. If the hypothesis that the direction of causation runs this way is to be at all plausible, we would need to speculate that Philosophy is one of a number of disciplines or activities that improve CRT score and which men are more likely to engage in than women (Fig. 4).

The causal story behind the gender gap in Philosophy is likely to be far more complex than is allowed by any of the possibilities discussed so far. An intelligent supporter of the Ideal Philosophical Personality Hypothesis would not claim that the only cause of the gender gap in Philosophy is that women lack the aspect of philosophical personality tracked by the CRT. A ‘perfect storm’ explanation of the gender gap seems more plausible, where many factors combine to produce the dramatic gender gap we see in Philosophy (Antony 2012). Figure 5 illustrates this with some hypothetical (but plausible) examples of other causal factors.

The interesting question is then whether the tendency for women to exhibit less of the trait(s) tracked by the CRT is one cause amongst many. Where a factor F is one cause amongst several (mutually independent) causes, we should be able to vary the other causes without this leading to a change in F. And yet, it is not clear that this would be the case here. For example, it seems plausible that were we to vary one of the social norms that contribute to the gender gap in Philosophy, this would also lead to a change in the CRT gender differential. In that case, this social norm would be a common cause of both the CRT gender differential and the gender gap in Philosophy, and the tendency for women to exhibit less of the trait(s) tracked by the CRT would not be a mutually independent cause of the gender gap in Philosophy.

To make this thought more concrete, we can take as an example the stereotype that women are more intuitive and less logical. This stereotype might make women less likely to imagine themselves as philosophers, with the consequence that they are less likely to continue in the discipline (Demarest et al. 2017). In that case, this stereotype is a causal factor in the gender gap in Philosophy. But the stereotype might also contribute by a more indirect route. For example, the stereotype may have the effect that adults are less likely to give girls toys that develop logic (Oksman 2016), with the consequence that girls have fewer opportunities to develop skills at whatever the CRT tracks. In that case, the stereotype acts as a causal factor in the CRT gender differential, which then feeds into women appearing less likely to have the ‘philosophical personality’ and there being fewer women in Philosophy. The gender gap in Philosophy, as well as the poorer performance of women on tasks like the CRT, would then provide further evidence for the stereotype. So, the stereotype would be causing several environmental interventions, which have effects that validate the stereotype (Fig. 6).Footnote 27

Fig. 6 Example of a more complex causal story Full size image

Stories like this, where there is a kind of causal feedback loop operating between different factors, seem plausible. To endorse this particular story would be to endorse a version of the Ideal Philosophical Personality Hypothesis, since it allows that there are fewer women in Philosophy partially as a result of women tending to lack an aspect of the philosophical personality. But it is a story that points against the Inaction Conclusion, because it blames women’s low CRT score not on innate differences in aptitude, but on contingent structural norms and cultural practices that would lessen or disappear in a fairer, more equal society. An implication of this is that tackling the structural injustice leading to the gender gap in CRT score would require far more than simply making changes within the discipline of Philosophy.

Whatever we think of that story, it should at least be clear that a straightforward causal arrow from CRT aptitude to the gender gap in Philosophy is highly implausible. The causal story is likely to be far more complex than any of the initial hypotheses allowed.