4.1.1 Replication

The first study’s aim was to replicate the findings from L&S (Reference Livengood and Sytsma2020) for the poisoned cup vignette. Figure 1a shows the mean agreement of our subjects ( $N = 71$ , male: 38, female: 33, mean age: 49.169) with the two statements presented to them:

Figure 1.

Means of agreements for the replication (1a); the first (1b) and second (1c) IOC exclusions; the CRC exclusion (1d); the CEQ exclusion (1e); and the simultaneous IOC, CRC, and CEQ exclusions (1f) with the poisoned cup vignette.

As can be seen in figure 1a (also see figures 12 and 13 in Supplementary Appendix C for relative frequencies), the findings from L&S (Reference Livengood and Sytsma2020) were successfully replicated with a German-speaking sample and a German translation of their vignette. Whereas L&S (Reference Livengood and Sytsma2020, 50) found a mean agreement of 7.00 with the first statement, we found a mean of 6.859 (95% confidence interval [CI] $ = \left[ {6.679,7.039} \right]$ ). For the second statement, they found a mean agreement of 2.06; we found a mean of 2.000 ( $95{\rm{\% }} \;CI = \left[ {1.569,2.431} \right]$ ). Wilcoxon signed-rank tests further revealed, as was the case in L&S’s study, that the difference to the neutral value of 4 on the scale from 1 to 7 was significant both for the first and the second statement ( $p \le 0.001$ ). ^{Footnote 7} Following L&S (Reference Livengood and Sytsma2020), this can be seen as an indication that subjects predominantly agreed with the statement that Gabi caused Nele’s death while disagreeing with the statement that Kathrin caused Nele’s death. The effect sizes for this were very large in the first case ( $r = 1.166$ ) and the second ( $r = - 0.842$ ). ^{Footnote 8}

4.1.2 Exclusion of the intermediary-ontology confusion (IOC) (1)

In order to avoid the IOC, we modified the statements slightly to focus on events instead of agents. This also replicated a modification done by L&S (Reference Livengood and Sytsma2020, 54–55). Subjects ( $N = 67$ , male: 35, female: 32, mean age: 48.970) now had to state their agreement with the following statements:

As can be seen in figure 1b (also see figures 14 and 15 in Supplementary Appendix C for relative frequencies), the mean agreement with the first sentence was equally high ( $M = 6.522$ , $95{\rm{\% }} \;CI = \left[ {6.176,6.868} \right]$ ). The mean agreement with the second statement, though, increased to 3.448 ( $95{\rm{\% }} \;CI = \left[ {2.823,4.072} \right]$ ). Again, this is very close to the findings from study 5 of L&S (Reference Livengood and Sytsma2020, 54f.), who reported a mean of 6.52 for the first statement and a mean of 3.36 for the second. A Wilcoxon signed-rank test indicated that the difference to the neutral value of 4 remained highly significant for the first statement ( $p \le 0.001$ ) but was no longer significant for the second one ( $p = 0.155$ ). The effect sizes were very large in the first case ( $r = 0.865$ ) but vanishingly small in the second ( $r = - 0.174$ ).

In sum, the indication that subjects predominantly disagreed with the statement that Kathrin caused Nele’s death seemed to decrease when the singular term referring to Kathrin was replaced by a singular term referring to an event involving Kathrin. However, as we expected, in accordance with study 5 of L&S (Reference Livengood and Sytsma2020), merely excluding the IOC did not lead to agreement with the second statement because of the CRC and the CEQ.

4.1.3 Exclusion of the intermediary-ontology confusion (IOC) (2)

In a further alteration aiming at avoiding the IOC, we focused on the respective actions without including Gabi’s or Kathrin’s name in the statements. This time, subjects ( $N = 81$ , male: 34, female: 55, mean age: 45.169) had to state their agreement with the following statements:

Figure 1c (also see figures 16 and 17 in Supplementary Appendix C for relative frequencies) shows that the mean agreement with the second statement further increased ( $M = 4.640$ , $95{\rm{\% }} \;CI = \left[ {4.116,5.164} \right]$ ). Here, a Wilcoxon signed-rank test showed that the difference to the neutral value of 4 now became significant at the 5% level for the second statement ( $p = 0.011$ ), showing at least a small effect ( $r = 0.270$ ). As we hypothesized, replacing a singular term denoting an individual with a singular term referring to an event had a greater influence on the agreement with the second statement if it did not mention an agent. ^{Footnote 9} We argue that the reason for this is that subjects did not consider the responsibility of the person involved in the event. However, as we expected, we still did not find a clear agreement with the intermediary being a cause of the next link of the causal chain because of the CRC and the CEQ.

4.1.4 Exclusion of the causality-responsibility confusion (CRC)

In order to outwit the CRC, we rephrased the statements as counterfactual conditionals avoiding the term cause. Here, subjects ( $N = 86$ , male: 40, female: 46, mean age: 43.256) had to state their agreement with the following sentences:

Figure 1d (also see figures 18 and 19 in Supplementary Appendix C for relative frequencies) shows that the mean agreement with the second statement clearly increased further ( $M = 5.953$ , $95{\rm{\% }} \;CI = \left[ {5.548,6.359} \right]$ ). A Wilcoxon signed-rank test revealed that the difference to the neutral value of 4 was now highly significant for this statement ( $p \le 0.001$ ), showing a large effect ( $r = 0.724$ ). We take this to be strong evidence in favor of our hypothesis that excluding the CRC by avoiding the use of the ambiguous word cause supports the CCAC. Presenting statements with counterfactual conditionals enables an investigation of the ordinary concept of causation and prevents the production of misleading evidence concerning the ordinary uses of the ambiguous word cause.

4.1.5 Exclusion of the cause-end questioning (CEQ)

In order to avoid the CEQ, we introduced the further intermediary of Nele’s action of ingesting poison into the causal chain. Hence, we presented the following three statements to subjects ( $N = 61$ , male: 27, female: 34, mean age: 48.295):

The mean agreement with every statement was higher than the neutral value of 4, as can be seen in figure 1e (also see figures 20–22 in Supplemenetary Appendix C for relative frequencies). Again, we are mainly interested in the second statement because we introduced a further intermediary of which Kathin’s action of giving Nele juice in a poisoned sippy cup is the cause. For the second statement, the mean agreement was 5.115 ( $95{\rm{\% }} \;CI = \left[ {4.501,5.728} \right]$ ). A Wilcoxon signed-rank test showed that the difference to the neutral value of 4 was highly significant for this statement ( $p \le 0.001$ ), with a moderate effect ( $r = 0.437$ ). We expected that changing the effect of Kathrin’s action to a less undesirable event would reduce the support of the CEQ to the CRC and thus would lead to a higher agreement. We found that even if the effect was only slightly less undesirable—causing someone to ingest poison might be only slightly better than causing someone to die—there was a highly significant agreement with the second statement as opposed to the agreement with the second statement of the replication. Thus, excluding the CEQ showed a clear effect supporting the CCAC, contrary to L&S (Reference Livengood and Sytsma2020).

4.1.6 Simultaneous IOC, CRC, and CEQ exclusion

Lastly, a set of subjects ( $N = 59$ , male: 30, female: 29, mean age: 45.610) was presented with sentences that combined the previous approaches. They had to state their agreement with the following sentences:

The mean agreement with every statement was higher than the neutral value of 4, as can be seen in figure 1f (also see figures 23–25 in Supplementary Appendix C for relative frequencies). The second statement was evaluated at 6.169 ( $95{\rm{\% }} \;CI = \left[ {5.695,6.644} \right]$ ). A Wilcoxon signed-rank test showed that the difference to the neutral value of 4 was highly significant for the second case ( $p \le 0.001$ ), exhibiting a large effect ( $r = 0.757$ ). Again, the agreement with the second statement with Kathrin’s action being the cause of the next link of the chain is of special interest to us. It has the highest agreement of all statements with Kathrin’s action being a cause. Clearly, the modifications of IOC exclusion, CRC exclusion, and CEQ exclusion do not suppress and might even support one another.

4.1.7 Summary

Figure 1 shows the means of our subjects’ agreement with the respective statements for the replication (figure 1a); the first (figure 1b) and second (figure 1c) IOC exclusions; the CRC exclusion (figure 1d); the CEQ exclusion (figure 1e); and the simultaneous IOC, CRC, and CEQ exclusion (figure 1f). Additionally, table 1 summarizes the statements presented in our studies on the poisoned cup vignette. Beyond the modifications of IOC exclusions (1) and (2), we can see a highly significant agreement with the second statement of each study, considering the intermediary to be a cause in the causal chain, contrary to L&S (Reference Livengood and Sytsma2020). Further, the two-sample Wilcoxon rank-sum tests comparing the statements of our modifications to those of our replication (right column of table 1) show that the second statement of each modification was evaluated significantly differently compared to our replication in each and every subsequent study. We take our results to be strong evidence in favor of the CCAC—contrary to the original findings of L&S (Reference Livengood and Sytsma2020). The design of L&S (Reference Livengood and Sytsma2020), we suppose, led subjects to understand the word cause as “being responsible for,” and hence, they tended not to agree with statements expressing that agents who do not share in the responsibility are causes. However, excluding the CRC by avoiding the ambiguous word cause, as well as the IOC and the CEQ both supporting the CRC, led, for the same vignette as used by L&S, to strong evidence in favor of the CCAC.

4.2.1 Replication

The first study aimed at replicating the findings from L&S (Reference Livengood and Sytsma2020) for the revolver vignette. Here, subjects ( $N = 63$ , male: 26, female: 37, mean age: 40.095) had to state their agreement with the following statements:

The mean agreement with the first statement from L&S (Reference Livengood and Sytsma2020, 60) was 6.705; our mean was 6.603 ( $95{\rm{\% }} \;CI = \left[ {6.285,6.922} \right]$ ), as can be seen in figure 2a (also see figures 26–29 in appendix C for relative frequencies). Statement (2) had a mean agreement of 2.490 in the original; our mean agreement was 3.000. The third statement’s original mean was 2.275; we found a mean of 2.984. Lastly, L&S (Reference Livengood and Sytsma2020) found a mean of 4.373 for the fourth statement; we found a mean of 5.048. ^{Footnote 10} Wilcoxon signed-rank tests showed that the first three statements from L&S (Reference Livengood and Sytsma2020) were significantly different from the neutral value of 4. ^{Footnote 11} The same holds true for our first ( $z = 7.108$ , $p \le 0.001$ ), second ( $z = - 3.288$ , $p \le 0.001$ ), and third statements ( $z = - 3.391$ , $p \le 0.001$ ). Only the last statement was evaluated differently from the original study; here, we found a significant deviation from the neutral value of 4 at the 1% level ( $z = 2.826$ , $p = 0.005$ ), whereas L&S found none. Overall, this suggests that subjects predominantly agreed with the statement that Leeve (or Trent in the original vignette) caused the death of Uwe (or Brad in the original vignette). At the same time, they disagreed with the statements that the hammer or the gunpowder caused Uwe’s (or Brad’s) death. Despite the slightly different means, we can consider this a successful replication of the original study. In the following, we will focus on statements (2) and (3), mentioning intermediaries that, contrary to the CCAC, were not rated to be causes in L&S (Reference Livengood and Sytsma2020) and in our replication.

Figure 2.

Means of agreements for the replication (2a); the IOC exclusion (2b); the CRC exclusion (2c); the CEQ exclusion (2d); and the simultaneous IOC, CRC, and CEQ exclusion (2e) with the revolver vignette.

4.2.2 Exclusion of the intermediary-ontology confusion (IOC)

The second study rephrased the statements to avoid the IOC. Subjects had to evaluate the following statements:

The responses to statements (2) and (3) are of special interest to us because subjects tended to disagree with them originally. As can be seen in figure 2b (also see figures 30–33 in appendix C for relative frequencies), subjects ( $N = 54$ , male: 26, diverse: 1, female: 27, mean age: 41.704) had a mean agreement of 3.667 ( $95{\rm{\% }} \;CI = \left[ {2.988,4.346} \right]$ ) for the second statement and a mean agreement of 3.593 ( $95{\rm{\% }} \;CI = \left[ {2.917,4.269} \right]$ ) for the third statement. Wilcoxon signed-rank tests showed that, in contrast to the replication described earlier, the mean agreements with the second ( $p = 0.357$ ) and third ( $p = 0.219$ ) statements were no longer significantly different from 4. Here, effect sizes were vanishingly small, though ( $r = - 0.125$ , $r = - 0.167$ ). It seems we can no longer infer that subjects would disagree with the statements that the release of the hammer or the explosion of the gunpowder caused Uwe’s death. That is, as expected, we see the same effect of the IOC exclusion for those statements subjects tended to disagree with in the replication as in the poisoned cup vignette: excluding the IOC led subjects not to disagree with statements they tended to disagree with when the IOC was not excluded.

4.2.3 Exclusion of the causality-responsibility confusion (CRC)

In a third study, subjects ( $N = 50$ , male: 18, female: 32, mean age: 42.980) were presented with counterfactual conditionals that omitted the word cause to avoid the CRC. We asked them to rate the following statements:

As can be seen in figure 2c (also see figures 34–37 in appendix C for relative frequencies), the mean agreements with statements (2) and (3) were distinctly higher than the neutral value of 4. For the second statement, the mean was 6.12 ( $95{\rm{\% }} \;CI = \left[ {5.582,6.658} \right]$ ); for the third, it was 5.720 ( $95{\rm{\% }} \;CI = \left[ {5.110,6.330} \right]$ ). Wilcoxon signed-rank tests showed that the mean agreement with statements (2) and (3) was indeed significantly different from the neutral value ( $p \le 0.001$ ). Effect sizes were large for both statements ( $r = 0.755$ , $r = 0.631$ ). When excluding the CRC, we found that subjects strongly agreed that both the release of the hammer and the explosion of the gunpowder were causes in the causal chain. As with the poisoned cup vignette, we take this to be strong evidence in favor of our hypothesis that excluding the CRC by avoiding the use of the ambiguous word cause supports the CCAC. Presenting statements with counterfactual conditionals enables an investigation of the ordinary concept of causation and prevents the production of misleading evidence concerning the ordinary uses of the ambiguous word causation.

4.2.4 Exclusion of the cause-end questioning (CEQ)

Next, we constructed a causal chain for the revolver vignette to avoid the CEQ. Here, subjects were shown the following statements:

Subjects’ ( $N = 53$ , male: 23, female: 30, mean age: 40.774) mean agreements with statements (2) and (3) were again above 4, as can be seen in figure 2d (also see figures 38–41 in appendix C for relative frequencies). The mean agreement with the second statement was 5.830 ( $95{\rm{\% }} \;CI = \left[ {5.272,6.389} \right]$ ), and the mean agreement with the third was 5.057 ( $95{\rm{\% }} \;CI = \left[ {4.396,5.717} \right]$ ). Wilcoxon signed-rank tests showed that the mean agreement was significantly different from the neutral value ( $p \le 0.001$ , $p = 0.003$ ). Here, effect sizes were large in the second case ( $r = 0.675$ ) and moderate in the third ( $r = 0.404$ ). Compared to the disagreements with statements (2) and (3) of the replication, subjects now tended to agree that the release of the hammer and the explosion of the gunpowder were causes in a causal chain. Thus, excluding the CEQ showed a clear effect in support of the CCAC.

4.2.5 Simultaneous IOC, CRC, and CEQ exclusion

Lastly, we presented a combination of the previous approaches. Here, subjects were given the following statements:

4.2.6 Summary

Figure 2 shows the means of our subjects’ agreements with the respective statements for the replication (figure 2a); the IOC exclusion (figure 2b); the CRC exclusion (figure 2c); the CEQ exclusion (figure 2d); and the simultaneous IOC, CRC, and CEQ exclusion (figure 2e). Additionally, table 2 summarizes the statements presented in our studies on the revolver vignette. Beyond the IOC exclusion, we can see significant or highly significant agreements with statements (2) and (3) in each study, with effect sizes being large or very large in all cases except one with a moderate effect size. Further, the two-sample Wilcoxon rank-sum tests comparing the statements of our modifications to those of our replication (right column of table 2) show that statements (2) and (3) of each modification beyond the IOC exclusion were evaluated significantly differently compared to our replication in each and every subsequent study. Hence, we take our results to be strong evidence in favor of the CCAC.

4.3.1 Replication

As with the other vignettes, we tried to replicate the findings from L&S (Reference Livengood and Sytsma2020) first. Hence, the subjects of our first study ( $N = 60$ , male: 30, female: 30, mean age: 50.667) had to rate the following statements:

Whereas the mean agreement of subjects in the study of L&S (Reference Livengood and Sytsma2020, 63) was at 5.48 and 3.67, respectively, for these two statements, we obtained means agreements of 5.483 ( $95{\rm{\% }} \;CI = \left[ {4.902,6.065} \right]$ ) and 4.117 ( $95{\rm{\% }} \;CI = \left[ {6.285,6.922} \right]$ ), as depicted in figure 3a (also see figures 46 and 47 in appendix C for relative frequencies). Similar to the original data from L&S (Reference Livengood and Sytsma2020), Wilcoxon signed-rank tests showed that the first statement was significantly different from the neutral value of 4 ( $p \le 0.001$ ); the second one, however, was not ( $z = 0.403$ , $p = 0.687$ ). Hence, the findings from L&S (Reference Livengood and Sytsma2020) seem to be replicable with a German-speaking sample and a German translation of their vignette.

Figure 3.

Means of agreements for the replication (3a); the IOC exclusion (3b); the CRC exclusion (3c); the CEQ exclusion (3d); and the simultaneous IOC, CRC, and CEQ exclusion (3e) with the GFCI vignette.

4.3.2 Exclusion of the intermediary-ontology confusion (IOC)

Trying to avoid the IOC by focusing on the events did not have much of an effect on the mean agreement with statement (2). Subjects ( $N = 64$ , male: 38, female: 26, mean age: 50.000) had to rate the following two statements:

The mean agreement with the second statement was 4.234 ( $95{\rm{\% }} \;CI = \left[ {3.596,4.873} \right]$ ), as can be seen in figure 3b (also see figures 48 and 49 in appendix C for relative frequencies). Again, a Wilcoxon signed-rank test indicated that the second statement was not different from the neutral value ( $z = 0.658$ , $p = 0.511$ ), showing practically no effect ( $r = 0.082$ ). That is, for the intermediary event, we found almost the same result as for the intermediary in the poisoned cup vignette expressed by statement (2) and for the intermediaries in the revolver vignette expressed by statements (2) and (3). Replacing individuals with events led to a neutral response to the respective statements.

4.3.3 Exclusion of the causality-responsibility confusion (CRC)

When we avoided the CRC by omitting talk of “causation,” we obtained a result that is, at first sight, surprising compared to the other vignettes. Here, subjects ( $N = 67$ , male: 37, female: 30, mean age: 46.267) had to rate the following statements:

The second statement was rated at 3.358 ( $95{\rm{\% }} \;CI = \left[ {2.720,3.996} \right]$ ), as represented in figure 3c (also see figures 50 and 51 in appendix C for relative frequencies). A Wilcoxon signed-rank test showed that it was not significantly different from the scale’s neutral value ( $p = 0.073$ ). The effect size was accordingly low ( $r = 0.254$ ). At first sight, this result might seem surprising. For the other vignettes, the CRC exclusion led to highly significant agreements with the statements depicting intermediaries as causes. But in this case, the agreement with statement (2) decreased compared to the second statements of the replication and the IOC exclusion. However, the story of the GFCI vignette makes the results plausible. Let us reconsider what happens in the vignette: the pipe burst; water ran into the outlet and made the GFCI break the circuit. What would have happened if there had been no GFCI installed in the circuit? The water in the outlet would have led to a short circuit, the special light would have turned off, and the experiment would have been ruined nevertheless. We take this to be commonsense knowledge. However, the GFCI safety mechanism reacts faster. Therefore, if there is a GFCI, then it breaks the circuit, but if there is no GFCI, the circuit breaks anyway. This means that we have a special case of preemption, with the GFCI safety mechanism breaking the circuit being the preempting cause and the short circuit being the preempted cause. As is well known, preemption is a major challenge for the counterfactual theory of causation (Lewis Reference Lewis1973): The breaking of the circuit by the GFCI causes the experiment to be ruined. However, subjects tend not to agree with statement (2) because the experiment would also have been ruined even if the GFCI had not broken the circuit (because of the short circuit). In light of this, we actually should have expected the results we obtained for the CRC exclusion. In general, confusing responsibility with causation because of the ambiguous meaning of the word cause cannot be ruled out by using counterfactual conditionals for cases including preemption. ^{Footnote 12} However, as we will see in the next section, the CEQ exclusion alone is sufficient for doing so.

4.3.4 Exclusion of the cause-end questioning (CEQ)

As for the other vignettes, we also constructed a causal chain to avoid the CEQ, using the following statements:

In this case, subjects ( $N = 64$ , male: 29, female: 35, mean age: 47.516) evaluated the second statement at 6.250 ( $95{\rm{\% }} \;CI = \left[ {5.835,6.665} \right]$ ), as can be seen in figure 3d (also see figures 52–54 in appendix C for relative frequencies). A Wilcoxon signed-rank test showed that this evaluation was significantly different from the neutral value ( $p \le 0.001$ ), with a large effect ( $r = 0.790$ ). Compared to the disagreements with statement (2) of the replication, subjects in this case strongly agreed that the breaking of the circuit by the GFCI was a cause in the causal chain that, in the end, led to a ruined experiment. The reason for this is that subjects did not consider the responsibility of the intermediary for the end link of the causal chain because of the CEQ exclusion. The CEQ, as applied by L&S (Reference Livengood and Sytsma2020), supported the CRC and thus led subjects to consider the responsibility of the intermediary for the ruined experiment. Thus, excluding the CEQ showed a clear effect in support of the CCAC.

4.3.5 Simultaneous IOC, CRC, and CEQ exclusion

Lastly, a combination of the previously described variations introduced the following statements:

Similar to the causal chain in section 4.3.4, subjects ( $N = 59$ , male: 38, female: 21, mean age: 51.356) evaluated statement (2) at 6.186 ( $95{\rm{\% }}\;CI = \left[ {5.734,6.639} \right]$ ), as can be seen in figure 3e (also see figures 55–57 in appendix C for relative frequencies). A Wilcoxon signed-rank test showed that, again, it was significantly different from 4 ( $p \le 0.001$ ), with a large effect ( $r = 0.775$ ). Again, we found a very high agreement for the GFCI safety mechanism breaking the circuit being a cause in the causal chain, contrary to the results of L&S (Reference Livengood and Sytsma2020). Apparently, the modifications of the IOC exclusion and the CRC exclusion, which both did not lead to an agreement with the respective second statements independently, were overruled by the CEQ exclusion. In sum, the simultaneous exclusion of the IOC, CRC, and CEQ strongly supports the CCAC, contrary to L&S (Reference Livengood and Sytsma2020).

4.3.6 Summary

Figure 3 shows the means of our subjects’ agreements with the respective statements for the replication (figure 3a); the IOC exclusion (figure 3b); the CRC exclusion (figure 3c); the CEQ exclusion (figure 3d); and the simultaneous IOC, CRC, and CEQ exclusion (figure 3e). Additionally, table 3 summarizes the statements presented in our studies on the GFCI vignette. For the CEQ exclusion and the simultaneous IOC, CRC, and CEQ exclusion, we found highly significant agreements with the respective second statements, which were evaluated significantly differently from our replication. However, we found an interesting pattern for the CRC exclusion that diverged from our results for the poisoned cup vignette and the revolver vignette, which we hypothesize resulted from the GFCI vignette involving a case of preemption. Hence, testing the concept of causation by counterfactual conditionals should have been expected to fail for this vignette. Nevertheless, the CEQ exclusion alone presents strong evidence supporting the CCAC for the same vignette as used by L&S.