CD Broad

CD Broad (1887–1971) was an English philosopher whose interests encompassed parapsychology and who theorized on topics such as precognition and post-mortem survival. He is noted in particular for his discussion of ‘basic limiting principles’ on the way things can be or be known, of particular relevance with regard to paranormal claims.


Charlie Dunbar Broad spent most of his professional career at Trinity College, Cambridge. As the Stanford Encyclopedia of Philosophy notes,

Broad’s interests were exceptionally wide-ranging. He devoted his philosophical acuity to the mind-body problem, the nature of perception, memory, introspection, and the unconscious, to the nature of space, time and causation. He also wrote extensively on the philosophy of probability and induction, ethics, the history of philosophy and the philosophy of religion. The ample scope and scale of Broad’s work is impressive. In addition he nourished an interest in parapsychology – a subject he approached with the disinterested curiosity and scrupulous care that is characteristic of his philosophical work.

Broad’s published thoughts on parapsychology appeared as early as 1925, in his monumental The Mind and its Place in Nature,1 and the views expressed there were developed further as his career progressed, most notably in another monumental book, Lectures on Psychical Research.2 Broad’s writing on parapsychology was confined primarily to the topics of ESP and postmortem survival. Psychokinesis, on the other hand, was a topic he dismissed more quickly than one would have expected, given the thorough attention and care he lavished on the cognitive forms of psi. For example, he wrote,

I do not myself think that the evidence for alleged supernormal physical phenomena is good enough to make them at present worth the serious attention of philosophers. I have no doubt that at least 99 per cent of them either never happened as reported or are capable of a normal explanation, which, in a great many cases, is simply that of deliberate fraud.3

It is surprising, then, and unfortunate, that Broad never published anything on the phenomena from the strongest cases of physical mediumship. It would have been interesting to see, for example, how he would have evaluated the case of DD Home, among others. Nevertheless, Broad’s extensive writings on other parapsychological topics remain a valuable legacy.

On the nature of ESP

Broad had a gift (or at least a penchant) for terminological innovation and clarification. One early and genuinely useful distinction he introduced concerns the forms of ESP. For example, Broad noted4 that one could not be content with defining ‘telepathy’ as, roughly, ‘feeling at a distance’, or ‘paranormal knowledge of a distant person’s thoughts’. He argued instead that one should distinguish telepathic-interaction from telepathic-cognition. In telepathic cognition, one individual A comes to know paranormally what another individual B is thinking or experiencing. But for telepathic interaction, we need only posit some sort of paranormal causal link between the minds of A and B, whether or not one of them comes to know anything about the other. Thus, in mere telepathic interaction one person’s thoughts about chocolate might cause a remote individual to think about chocolate, or about candy, without the latter knowing anything about the thoughts of the former.

Similarly, clairvoyance is not simply ‘clear seeing’ or ‘direct knowledge of remote states of affairs’; one should distinguish clairvoyant-cognition from mere clairvoyant-interaction. The former would indeed be a kind of knowledge of remote states of affairs, but the latter would merely be a kind of direct influence of remote events on one’s mind. Thus, an example of the former would be knowledge of the occurrence of a remote fire; an example of the latter would be the remote fire simply causing the subject to have thoughts about fire.

Broad also offered a very clear and useful discussion of some difficulties in explaining ESP – in particular, explaining how ESP can be selective. To see what the issues are, consider the DT (down-through) clairvoyance test, in which a playing card deck is placed face down and the subject (say, in another room) tries to guess the order of cards, from the top of the deck down through. And let us suppose that the sixth card down is the eight of diamonds.

Let us also suppose that – as is the case in ordinary sense perception – information of some sort is coming from this card, somehow reaching the subject, and thereby allowing for clairvoyant interaction or cognition. But then, if the sixth card down is generating information that can be clairvoyantly detected, then so are all the other cards in the deck. In fact, everything in the world would also be generating information that could be clairvoyantly detected. So how can the subject cut through all that clairvoyantly-accessible information and focus on just the sixth card down?

As Broad noted, this seems impossible if we take clairvoyance to be an emanative or physically emissive process like sight or hearing. In both of those cases, we can see or hear objects because of the information they give off – for example, the selective reflection of light waves in the case of sight, and the transmission of sound waves in the case of hearing. So if clairvoyance is modeled after those sense modalities, consider all that must happen for the subject to detect clairvoyantly that the sixth card down is the eight of diamonds.

First, the subject must discern that there are eight (no more, no less) outstanding patches on the surface of the card. Second, the subject must discern that those patches are diamond-shaped. We could also add a third condition, that the subject can tell that the patches are red in color. However, the first two conditions pose enough problems on their own.

Now consider some of the key assumptions that must be made if we are to explain the subject’s ability to single out that particular card by means of clairvoyant emanations generated by the card. First, we must assume that the subject’s body is being stimulated by emanations from the front of the sixth card down, even though the front of the card may not be facing him. Second, we must assume that other objects (including the other cards and other intervening objects are transparent to this emanation, although they are not transparent to light. Third, we must assume that emanations from all the other cards and other intervening objects are also reaching the subject. Fourth, we must assume that although the emanations from the cards are not light waves, there is nevertheless a difference between the emanations from the diamonds and other things (including the background of the card), so that the subject can tell how many diamonds there are, or simply what shape the objects on the card are.

Similar problems arise for explaining telepathy – in particular, how to distinguish the mental state of A from that of all the other people simultaneously having mental states. Of course, the temptation in the case of telepathy is to invoke a broadcasting analogy and suppose that the subject simply ‘tunes’ to the appropriate frequency. But quite apart from deep and fatal conceptual weaknesses in the ‘brain radio’ model of telepathy,5 it remains a mystery how the subject can tune in to the appropriate signal.

It should be noted that Broad never intended to show that ESP is inexplicable by either current or future science. He intended merely to show that ESP does not seem analogous to any normal form of sense perception.

Basic Limiting Principles

Perhaps Broad’s best-known work in parapsychology is his attempt to mark off the domain of the paranormal by appealing to what he called ‘basic limiting principles’ (BLPs). The most exhaustive presentation of Broad’s view appears in his essay ‘The Relevance of Physical Research to Philosophy’6; it is also sketched in his later Lectures on Psychical Research.7

Definition of BLPs

Broad’s BLPs are called limiting principles because they specify restrictions or limitations on the way things can be, or the way they can be known. And they are called basic because they are supposed to lie at the very foundation of our conceptual system. Broad writes, ‘They form the framework within which the practical life, the scientific theories, and even most of the fiction of contemporary industrial civilization are confined’.8 BLP’s are thus not merely laws of nature. Although, according to Broad, there may be borderline cases in which we cannot tell whether we have a BLP or a natural law, in general BLPs are more basic to our conceptual system than laws of nature. In fact, BLPs are presupposed by our natural laws (in a sense to be explained below). It is precisely because we share certain BLPs that our natural laws (and hence our sciences) take certain forms rather than others.

Broad’s taxonomy of BLPs differs among his various accounts, and even in his thorough exposition in ‘The Relevance of Psychical Research to Philosophy’ he does not claim to offer a complete list of BLPs. Rather, he presents some examples and assumes we can extrapolate from those. In the summary of his position in the Lectures, Broad lists the following four BLPs, which he seems to regard as especially important, and which (for the most part) are drawn or condensed from his earlier and more extensive list.

The first BLP imposes limitations on the ways we can acquire knowledge of another person’s thoughts or experiences.

(1) We take for granted that a person A cannot know what experiences another person B is now having or has had, except in one or another of the following three ways. (i) By hearing and understanding sentences uttered by B, or reproductions of such sentences, which describe his experiences; or by reading and understanding such sentences written or dictated by B, or reproductions or translations of them. Or (ii) by hearing and interpreting interjections which B makes, by seeing and interpreting his movements, gestures, facial expressions, and so on. Or (iii) by seeing, and making inferences from, certain persistent material objects, e.g., tools, pottery, pictures, etc., which B has constructed or used, or copies and reproductions of such objects.9

The second BLP restricts how we can come to know about the future.

(2) We take for granted also that a person cannot foresee (as distinct from inferring, or being led, without explicit inference, to expect on the basis of regularities in his past experience) any event which has not yet happened.10

The third BLP restricts how we can cause change in the physical world.

(3) We take for granted, too, that a person cannot directly initiate or modify by his volition the movement of anything but certain parts of his own body.11

The fourth BLP concerns the dependence of mind on brain and, more specifically, survival after death.

(4) We take for granted that, when a person’s body dies, the personal consciousness, which has been associated with it and expressed through it during his lifetime, either ceases altogether or, if not, ceases to be able to manifest itself in any way to those still living on earth.12

With this partial list of BLPs, we are in a position to consider Broad’s definitions. First, Broad offers the following definition of a phenomenon’s abnormality.

(D1) Phenomenon P is abnormal: P seems prima facie to conflict with a well-established law of nature, but not with any BLP.

Broad remarks that sometimes abnormal phenomena do not really conflict with any laws of nature, but can be explained in terms of existing laws and certain unusual boundary conditions. On the other hand, he says, sometimes abnormal phenomena show us that laws have exceptions, or that we need to supplement or revise our original set of laws.

Critique of Broad’s BLPs

Before considering what Broad says about paranormality, we should at least note that his account of abnormality is not entirely satisfactory. Many phenomena widely regarded as abnormal (such as Siamese twins, or situs inversus, a congenital condition in which the position of internal bodily organs is laterally transposed) are characterized as such even though they do not seem prima facie to violate a natural law. Moreover, the class of abnormal phenomena is not the same as the class of unusual or infrequent phenomena, although those classes overlap. For example, great natural disasters like floods and earthquakes, or such predictable occurrences as solar eclipses and the passage of famous comets are unusual and infrequent, but we do not regard them as abnormal. Broad’s treatment of abnormality, then, leaves that concept somewhat obscure.

At any rate, given the way Broad chooses to characterize abnormality, his account of paranormality is what one would expect.

(D2) Phenomenon P is ostensibly paranormal: P seems prima facie to conflict with one or more of the BLPs, and not merely with some well-established law of nature.

(D3) Phenomenon P is genuinely paranormal: P in fact conflicts with one or more of the BLPs.

Unfortunately, this account has some well-known limitations.13 Although Broad notes that paranormal phenomena run up against something more fundamental than – or at least something in addition to – the dictates of science, his account may not go deep enough. That is because Broad has failed to explain what, in general, a phenomenon must conflict with in order to conflict with a BLP. In short, one could argue that Broad’s itemization of BLPs is of little value in the absence of a general characterization of a BLP.

For one thing, it is plausible to regard the domain of the paranormal as something that may change with time, as our thinking about the world becomes more sophisticated. After all, that is presumably why phenomena formerly regarded as weird or other-worldly have come to be seen as more or less commonplace and quite this-worldly. But if the extension of the term ‘paranormal’ (that is, the range of things to which the term applies) can change with time, then arguably we need a general characterization of what a paranormal phenomenon is, regardless of the vagaries of intellectual history. Hypnosis, we must recall, was once regarded by the Society for Psychical Research as a phenomenon deserving to be investigated along with those we now call by names such as ESP and PK. But it does not seem to violate any of Broad’s BLPs, and the underlying mechanisms or processes are still not understood.

Also, even if we restrict attention to a particular historical epoch, a partial list of BLPs will not suffice to explain what the domain of the paranormal is for that epoch. For one thing, Broad’s BLPs are by no means universally shared even within our own historical epoch, or even among those who agree on what phenomena count as ostensibly paranormal. For example, many people believe they can communicate with the surviving spirits of the deceased, and they nevertheless regard this phenomenon as distinct from both the normal and the abnormal. Their rejection of BLP (4) thus seems compatible with treating ostensible postmortem communications as paranormal.   

But even if the BLPs were universally shared, we might still – quite reasonably – want to know the principle behind a phenomenon’s proper classification as paranormal, no matter which historical epoch we are concerned with or which set of BLPs we now have. No mere list (no matter how exhaustive) can indicate what a BLP is, especially if the items on the list can change as they do in Broad’s different accounts. We are left wondering: What makes these enumerated principles examples of BLPs?   

Some may wish to make Broad’s account more general by saying that paranormal phenomena violate one or more of whatever it is that science presupposes (and also forms the framework of our lives and theories). John Beloff may have had something like this in mind when he wrote ‘A phenomenon is, by definition, paranormal if and only if it contravenes some fundamental and well-founded assumption of science’.14   

But that seems to take too great a step in the direction of generality. After all, we presuppose much more (in both science and life) than the sorts of principles Broad lists as BLPs, which seem equally to form part of our conceptual framework, and which are not even prima facie violated by ostensibly paranormal phenomena – for example, regulative principles like the laws of deductive logic, as well as general assumptions about such things as the viability of the hypothetico-deductive method, the general veridicality of perceptions, or the existence of other minds, and specific assumptions about (say) the fact of our own existence.   

Thus, even if paranormal phenomena do violate certain scientific presuppositions, it appears that only one or more members of a subset of the things presupposed in science (and life) must be violated in order for a phenomenon to be paranormal. But which subset? Putting the matter this way, we see that we need some way to characterize that subset generally. And that is precisely what Broad’s account fails to address.   

Another important issue left unresolved by Broad’s account is this: Are BLPs in fact more fundamental than laws of nature? Put another way, is it reasonable to suppose, as Broad did, that BLPs are presupposed rather than implied by scientific theory? The question is both relevant and important, because Broad claims that ostensibly paranormal phenomena seem to conflict with something more fundamental than scientific theory. But if they are merely implied by scientific theory, BLPs are not more fundamental; a phenomenon that seems prima facie to conflict with BLPs may then conflict only with one or more of the consequences of scientific laws. And in that case, Broad would have unwittingly committed the obvious error of linking a phenomenon’s paranormality merely to its scientific inexplicability.   

So the question remains: Do our scientific theories have the form they have (describe the world as they do) because the BLPs are taken for granted from the start, or are the BLPs taken for granted because certain physical principles or laws are assumed to be true?   

Broad would have said that our theories take the forms they do because we already have a pre-theoretic view of the world, of which the BLPs form a central part. But there are two ways of construing that claim, one of which is patently false, and the other of which is at least suspicious (and not simply because the notion of a BLP is obscure).   

(i) Broad might have been making an historical claim about acquiring ideas. He might have been maintaining that the acceptance of scientific theory follows the acceptance of the BLPs. But that seems quite clearly to be false, because the BLPs are by no means universally held, even among those who accept current scientific theory. For example one can accept current scientific theory and still believe in the reality of postmortem survival. That is because one can hold that the domain of the allegedly relevant (presumably physical) sciences is more restricted than scientists tend to believe, so that (for example) mental phenomena generally fall outside that domain.   

(ii) Thus, it is more likely that Broad was making a claim about what may loosely be termed the logic of belief – that is, a claim about the structure of a fully articulated world view or conceptual scheme. Presumably, Broad was maintaining that if we made fully explicit the system of beliefs constituting our total world view, its structure would be such that accepting the BLPs was a necessary condition for accepting our scientific theories.   

The structure of this fully articulated conceptual system would apparently not be like that of an axiomatic system (with the BLPs functioning like axioms), because the BLPs presumably support divergent and possibly even mutually incompatible scientific theories (for instance, Copernican and relativistic physics seem equally to presuppose Broad’s BLPs). But within the articulated conceptual system, BLPs and scientific theories are nevertheless supposed to have clearly distinct roles, with that of the BLPs being the more fundamental. Although we could abandon or revise scientific laws or theories without repudiating any BLPs, if we gave up a BLP we would also have to abandon the laws and theories that rested on it. And if we gave up all our BLPs, we would be forced to scuttle our entire stock of scientific theories. Furthermore, since the BLPs may support rival theories, then by repudiating our BLPs we would be forced to jettison an indefinitely large supply of rival theories in addition to the prevailing ones.

From this point of view, it is easy to explain how people might accept prevailing scientific theories while rejecting one or more of the BLPs. Presumably, they simply fail to see the logical connections between those theories and the BLPs. That is, they fail to see that the former presuppose the latter.

Although (ii) is perhaps a more plausible construal of Broad’s position than (i), it nevertheless rests on the mistaken belief that a conceptual scheme or framework has a discernible logical structure, one in which the distinction between a theory’s implications and its presuppositions is determinable. Granted, sometimes we can draw this distinction with considerable precision, but only relative to theories with a well-defined structure of a certain sort. We can distinguish a theory’s implications from its presuppositions only when we can order its constitutive statements systematically in terms of their logical function and interdependence. But most theories in the natural sciences, and certainly the more informal cognitive structures we call ‘worldviews’ or ‘conceptual schemes,’ are too ill-defined and loose-knit for us to distinguish clearly between the theories’ implications and presuppositions, or between the basic and non-basic elements of the conceptual schemes.

Therefore, it is difficult to assess Broad’s claim that his BLPs lie at the very foundation of our conceptual scheme, and in fact that claim seems to be false. It is not at all clear that there is any set of beliefs sufficiently fundamental and sufficiently widely shared to count as our conceptual scheme. And besides, even if the BLPs were universally or almost universally shared, their importance and logical relations to the rest of our beliefs may be both unclear and different for different people.

Actually, it is questionable whether science is connected in any interesting way to Broad’s BLPs. Granted, some specific theories seem to presuppose certain of Broad’s BLPs. For example, our theories of perception may rest on BLP-like presuppositions about how information about the world can be acquired. However, since they appear to deal only with familiar forms of information-acquisition, standard theories of perception might be compatible with the possibility of extra-sensory or non-sensory modes of acquiring information.

In any case, it is unclear why our acceptance of (say) the theory of relativity or of quantum physics rests on our acceptance of any of Broad’s BLPs. Relativity, for example, seems compatible not only with Broad’s four BLPs but with their denials as well. Broad may simply have assumed uncritically that the admission of genuine psi phenomena would automatically wreak the deepest havoc in science. In fact, that assumption seems to have been widespread and long-standing even within parapsychology. But it may be less true today, due primarily to the efforts of some influential investigators – for example, Helmut Schmidt, Harris Walker and Dick Bierman – who have been trying to reconcile backward causation and other puzzling features of psi phenomena with the traditional framework of contemporary physics.

Considering the difficulties in interpreting Broad’s view and trying to make it (or something like it) viable, it is not surprising that there has been little interest in pinning down the meaning of ‘paranormal’ since the mid-twentieth century.

On Precognition

Some of Broad’s earliest publications on parapsychology dealt with the topic of precognition and foreknowledge,15 and it is a subject to which he returned several decades later.16 To appreciate Broad’s position, it will be helpful first to address some preliminary considerations about the definition of ‘precognition’.

Perhaps the first thing we should note is that the loose and popular ways of talking about precognition are extremely misleading. For one thing, many events tentatively classified as precognitive are not cognitions (examples of knowledge) at all. But that should come as no surprise, because we have already noted that telepathy and clairvoyance seem often to be non-cognitive—that is, examples merely of telepathic or clairvoyant interaction. So we can reject immediately one customary way of defining ‘precognition’ – namely, as simply ‘the non-inferential knowledge (or, even less plausibly, as the perception) of some future state of affairs.’

Moreover, people frequently treat precognitive phenomena as experiences of some kind. If we confine ourselves to the sorts of incidents described in anecdotal reports of apparent spontaneous precognitive events – unusually vivid dreams, or waking visions or hallucinations – that characterization is somewhat reasonable. But in the laboratory setting the evidence for precognition often has little or nothing to do with notable experiences on the part of the subject. Instead, it might consist merely of time-displaced correlations between a series of guesses and a series of targets.

Generally speaking, when the experimental evidence for precognitive ESP involves time-displaced hits between call and target sequences, subjects report no unusual experiences at all (the calls are often made in rapid succession), much less experiences which appear to the subject to be forecasts or to be about the future (prospective experiences, to use Broad’s terminology, as contrasted with retrospective experiences). In fact, even in successful laboratory studies of apparently precognitive dreams, or in ganzfeld-type precognition tests, the subject’s experiences are typically not about the future. That is, nothing in the experiences themselves ‘refers’ or points to the future, or strikes the experient as having to do with the future. It is true that the content of the experience is often judged to correspond in intriguing ways to some later event, but that is another matter.

Still, even though a precognitive event need not terminate in an awareness or a precognitive experience, it seems safe to say that it will terminate in a mental state of some kind or perhaps just a bit of behavior (such as a ‘guess’ about the next card to be turned up, or perhaps an impulse to act). In other words, it seems safe to say that a precognitive event produces a state of a person. That is hardly an earth-shattering revelation, but it suggests that we can give at least a preliminary and tentative causal characterization of precognition, in terms of precognitive states, somewhat as follows:

State s of person P is precognitive: a causal condition of s is some state of affairs occurring later than s.

This, clearly, is a version of the familiar retrocausal approach to interpreting precognition, according to which precognitions are caused by later events. Notice that this definition does not distinguish precognition from retroactive PK or, for that matter, retroactive clairvoyance or telepathy. That might even be viewed as a virtue by those who regard the traditional divisions of psi phenomena as arbitrary or otherwise unsupportable.

Indeed, there seem to be two distinct traditions in parapsychology regarding the relationship of precognition to other forms of ESP. According to one, precognitive phenomena are simply time-displaced modes of either telepathy or clairvoyance. According to the other, precognitive phenomena are distinct from and independent of other psi phenomena (including telepathy and clairvoyance). This seems to have been Broad’s view. He writes:

If the admitted facts of a case of ostensible precognition could be certainly or plausibly explained in any one, or any combination, of the following ways, we should decline or hesitate to call it a case of genuine precognition. The alternative explanations…may be divided into (a) those involving nothing but normal factors; (b) those involving factors which are abnormal, but not paranormal; and (c) those involving paranormal factors.17

Broad’s examples of paranormal explanations of ostensibly but not genuinely precognitive events include the following. Person A might seem to know precognitively what B will do; but this might be due to A’s telepathic knowledge of B’s disposition or intention to perform that action. Or perhaps A unwittingly desires B to perform that action, and A’s unconscious desire acts telepathically (or psychokinetically) on B as a kind of hypnotic suggestion. These would be examples of what Jule Eisenbud called the ‘active analysis’ of precognition.

Interestingly, and distinctively, Broad objected not only to a retrocausal account of precognition. Rather, he objected to any sort of causal account of precognition. For, Broad, if event X is a precognition of a later event Y, then (a) it cannot be a chance occurrence that Y follows X, and (b) ‘there can be no influence, direct or indirect, either of X on the occurrence of Y or Y on the occurrence of X, and … X and Y cannot both be causal descendants in different lines of causal ancestry, of a common cause-factor W.’18

The point of condition (b) is to rule out any causal link (normal, abnormal, or paranormal) between X and Y. Although Broad is not entirely explicit, his intuition seems to be that a precognized event cannot be a causal consequence of its precognition, either directly (in which case Broad, in the spirit of Eisenbud, might call it PK or telepathic influence) or through some common causal ancestor. Broad never defends this intuition; nevertheless, those open to the possibility of retrocausation would probably sympathize with the idea that precognition would not involve temporally orthodox, clockwise, causal connections.

However, Broad also felt that Y cannot be a causal condition of X, and thus he rejected the retrocausal analysis of precognition. As he saw it, at the time of X, Y is just an unrealized possibility, and as such it can have no causal consequences at all. Now whether or not we share Broad’s intuitions, we can see why he regarded the notion of precognition as internally problematical. Conditions (a) and (b) above cannot jointly be satisfied. If (b) is satisfied – that is, if there is no causal connection between the precognitive event X and the later event Y of which X is an ostensible precognition, then Y’s following X can only be fortuitous; hence, condition (a) cannot then be satisfied.

As readers may realize, Broad’s claim that future events are unrealized possibilities would be challenged by contemporary physicists who consider time to be an inseparable component of a four-dimensional spacetime continuum (or block universe). They would claim that physics compels us to regard world history as existing in its totality in some timeless sense, and that the unrealized quality of future events is a function of the epistemic limitations of human consciousness rather than a mind-independent feature of nature.

On Postmortem Survival

Broad’s writings on apparitions (of both the living and the dead) and mental mediumship are extensive and rewarding, although his discussion of the differences between mental mediumship and multiple personality relies too heavily on an outdated understanding of the latter.19 His most singular contribution to the literature on survival is probably his analysis of the survival hypothesis – specifically his discussion of what it is that might survive bodily death and dissolution.20

In order to explain what he means by ‘human personality’, Broad relies on a distinction familiar to philosophers, between mental states existing occurrently and dispositionally. For example, it can be true that a person remembers a past auto accident even though at that time no particular memory episode or experience concerning that event is taking place. That is because one can recall the relevant information about the accident under various circumstances, either spontaneously or on demand. So we would say that the person has that memory dispositionally rather than occurrently.

Now Broad accepted the familiar view according which survival presumably would involve the persistence of much or most of what is distinctive about a person’s psychology or personality – for example, memories, interests, character traits, and so on. But these features of the person would be retained postmortem in a dispositional  form. And he argued that it is this dispositional aspect of one’s mentality which forms the basis of the personality, and which cases of apparent survival suggest persists after death. He writes,

It seems to me that a necessary, though by no means a sufficient, condition for survival is that the whole or some considerable part of the dispositional basis of a human being’s personality should persist, and should retain at least the main outlines of its characteristic type of organization, for some time after the disintegration of his brain and nervous system.21

Then, after noting that ascribing a disposition to something is to assert a certain kind of conditional or hypothetical proposition about it, Broad asserts,

… we do unhesitatingly take for granted that there must be, at the back of any such purely conditional fact, a categorical fact of a certain kind, viz. one about the more or less persistent structure of the thing in question, or about some more or less persistent recurrent process going on within it.

For example, just as salt’s dispositional property of solubility is explicable in terms of underlying categorical (non-dispositional) properties of salt, a person’s dispositional personality or mental states (say, the trait of friendliness, or the memory of an auto accident) will be explicable in terms of underlying non-dispositional, or categorical, states.22

Broad continues

Now it is easy to imagine a persistent minute structure in a human being considered as a physical object. It is also easy to imagine recurrent processes, e.g. rhythmic chemical changes, changes of electric potential, etc., going on in the minute parts of a human being considered as a physical object. But it is very difficult to attach any clear meaning to phrases about persistent purely mental structure, or to the notion of purely mental processes, other than trains of experience of various kinds, with which each of us is familiar through having had them, noticed them, and remembered them. So it is not at all clear what, if anything, would be meant by ascribing to a human being, considered as a psychical subject, either a persistent purely mental structure or recurrent non-introspectable mental processes. Thus, it is almost inevitable that we should take for granted that the dispositional basis of a human being's personality resides wholly in the minute structure of his brain and nervous system and in recurrent physical processes that go on within it.23

Broad then notes that

… on this assumption, it seems plain that it is impossible for the dispositional basis of a man's personality to exist in the absence of his brain and nervous system; and therefore impossible for it to persist after the death and disintegration of his body.24

Broad’s well-known proposed solution to this problem is the following.

Unless we are willing to drop the principle that every conditional fact about a thing must be grounded on a categorical fact about its persistent minute structure or recurrent internal processes, there seems to be only one view of human nature compatible with the possibility of the post mortem persistence of the whole, or any part, of the dispositional basis of a human being's personality. We must assume some variant of the Platonic-Cartesian view of human beings. This is the doctrine that every human being is some kind of intimate compound of two constituents, one being his ordinary everyday body, and the other something of a very different kind, not open to ordinary observation. Let us call the other constituent in this supposed compound a ‘Ψ-component'. It would be necessary to suppose that the Ψ-component of a human being carries some part at least of the organized dispositional basis of his personality, and that during his life it is modified specifically and more or less permanently by the experiences which he has, the training which he receives, his habitual practical and emotional reactions towards himself and others, and so on.25


… the notion of a Ψ-component is, by definition, the notion of something which carries the structural basis of that system of organized dispositions (cognitive, conative, and emotional) which is absolutely essential to anything sufficiently complex and stable and self-coherent to be counted as a personality.26

Broad is quick to caution that

We need not assume that a Ψ-component by itself would be a person, or that it would by itself be associated with a stream of experience even at the animal or the biotic level, such as that enjoyed by a cat or by an oyster. It might well be that personality, and even the lowliest form of actual experience, requires the association of a Ψ-component with an appropriate living organism.27

But suppose we are willing to assume that this Ψ-component and its underlying patterns or structure can persist after bodily death, but not as an ordinary physical body. Suppose instead that it can persist more like a broadcast of an orchestral performance that is not yet picked up by any suitably tuned receiver, but which exists still in the form of signals in the air. Broad suggests we can thereby

… conceive a form of dualism, not inconsistent with the known facts of physics, physiology, and psychology, which would make it not impossible for the dispositional basis of a human personality to persist after the death of the human being who had possessed that personality.28

Broad concludes, then, that the dispositional basis of a person’s ‘personality (or at any rate some part of it) might continue to exist and to be organized in its former characteristic pattern, at least for a time after the death of his body, without being associated with any other physical organism.’29

Next, Broad is quick to note (correctly) that the evidence for ESP does not lend any direct support to this proposed dualistic view. Good evidence for ESP would show only that the orthodox conception of human (or animal) ability to acquire information about the world needs to be expanded. Similarly, he observes, a postulated dualism does not entail the existence of psi abilities.    

The discussion that follows this is characteristically nuanced and too complex to be summarized here. Suffice to say that, after a survey of the types of paranormal phenomena suggesting survival, Broad concludes, somewhat ambivalently:

In the known relevant normal and abnormal facts there is nothing to suggest, and much to counter-suggest, the possibility of any kind of persistence of the psychical aspect of a human being after the death of his body. On the other hand, there are many quite well attested paranormal phenomena which strongly suggest such persistence, and a few which strongly suggest the full-blown survival of a human personality …

I think I may say that for my part I should be slightly more annoyed than surprised if I should find myself in some sense persisting immediately after the death of my present body. One can only wait and see, or alternately (which is no less likely) wait and not see.30

Probably Broad’s most important works dealing with parapsychology are the books Religion, Philosophy and Psychical Research31 and Lectures on Psychical Research.32 However, readers should be warned that the latter’s discussion of the laboratory evidence for ESP focuses very heavily (but not exclusively) on SG Soal’s card-guessing experiments, which were subsequently discredited (see Samuel Soal). In any case, the most valuable and original portions of Broad’s Lectures are the analyses of spontaneous forms of ESP and the evidence for and implications of mediumship. Because more than 75 percent of the book deals with these topics, Broad’s Lectures remains a classic text and repays careful study.

Stephen E Braude


Beloff, J. (1978). Explaining the Paranormal, with Epilogue – 1977. In Philosophy and Parapsychology, ed. by J. Ludwig, 353-70. Buffalo: Prometheus.

Braude, S.E. (1988). Mediumship and Multiple Personality. Journal of the Society for Psychical Research 55, 177-95.

Braude, S.E. (1995). First Person Plural: Multiple Personality and the Philosophy of Mind (revised edition). Lanham, MD: Rowman & Littlefield.

Braude, S.E. (2002). ESP and Psychokinesis: A Philosophical Examination (revised edition). Parkland, FL: Brown Walker Press.

Braude, S.E. (2016). Mediumship and Multiple Personality. Psi Encyclopedia. London: The Society for Psychical Research.

Broad, C.D. (1925). The Mind and Its Place in Nature. London: Kegan Paul, Trench, Trubner & Co. Ltd.

Broad, C.D. (1935a). Mr. Dunne's Theory of Time. Philosophy 10/38, 168-85. Republished in Religion, Philosophy and Psychical Research (1953), ed. by C.D. Broad, 68-85. London: Routledge & Kegan Paul.

Broad, C.D. (1935b). Normal Cognition, Clairvoyance, and TelepathyProceedings of the Society for Psychical Research 43, 397-438. [Republished in Religion, Philosophy and Psychical Research (1953), ed. by C.D. Broad, 27-67. London: Routledge & Kegan Paul.]

Broad, C.D. (1937). The Philosophical Implications of Foreknowledge. In Knowledge and Foreknowledge. Proceedings of the Aristotelian Society, Supplementary 16, 177-209. London: Wiley.

Broad, C.D. (1949). The Relevance of Psychical Research to Philosophy. Philosophy 24, 291-301. Republished in Religion, Philosophy and Psychical Research (1953), ed. by C.D. Broad, 7-26. London: Routledge & Kegan Paul.

Broad, C.D. (1953). Religion, Philosophy and Psychical Research. London: Routledge & Kegan Paul. Originally published in Philosophy 24 (1949), 291-309.

Broad, C.D. (1962/2011). Lectures on Psychical Research. London: Routledge & Kegan Paul.

Broad, C.D. (1967). The Notion of Precognition. In Science and ESP,  ed. by J.R. Smythies, 165-96. London: Routledge & Kegan Paul.

Sudduth, M. (2016). A Philosophical Critique of Empirical Arguments for Postmortem Survival. New York & London: Palgrave Macmillan.




  • 1. Broad (1925).
  • 2. Broad (1962).
  • 3. Broad (1937), 177. See also, Broad (1925), 652.
  • 4. In Broad (1935b).
  • 5. See Braude (2002).
  • 6. Broad (1949).
  • 7. Broad (1962).
  • 8. Broad (1962), 3.
  • 9. Broad (1962), 3.
  • 10. Broad (1962), 3-4.
  • 11. Broad (1962), 4.
  • 12. Broad (1962), 4.
  • 13. For a detailed discussion, see Braude, 2002.
  • 14. Beloff (1978).
  • 15. Broad (1935a, 1937).
  • 16. Broad (1967).
  • 17. Broad (1967) 182.
  • 18. Broad (1967), 194.
  • 19. Braude (1988, 1995). See also Mediumship and Mutiple Personality.
  • 20. The central text is the chapter, ‘Human Personality, and the Question of the Possibility of its Survival of Bodily Death’ in Broad (1962). For a penetrating recent discussion of this work, see Sudduth (2016).
  • 21. Broad (1962), 414, italics in original.
  • 22. Broad (1962).
  • 23. Broad (1962), 414-15, italics in original.
  • 24. Broad (1962), 415.
  • 25. Broad (1962), 415, italics in original.
  • 26. Broad (1962), 421.
  • 27. Broad (1962), 415, italics in original
  • 28. Broad (1962), 416-17.
  • 29. Broad (1962), 417.
  • 30. Broad (1962) 430.
  • 31. Broad (1953).
  • 32. Broad (1962).