Opacity of Mind in Buddhism
In various Nyingma Buddhist groups in Nepal there is a local theory of mind that, most basically, holds that you can not ever know what another person is thinking. This is a phenomenon that I have come across in relation to both the Sherpa and Yolmo peoples, and there are likely others as well. For example, in Sherry Ortner's book High Religion she describes a usual situation:
“If one asks why somebody did something, one gets a shrug and a one-word answer…, or even a hostile response: “How should I know, we can’t see into other people’s heads?” (p. 216, footnote 17)
It can easily be said that many groups share such an understanding - but the thing that strikes me about the literature is the pervasiveness of this attitude and the way it influences people's attitudes towards interacting with each other.
I know there are some similar lines of thought in the Western philosophy tradition (such as David Chalmers's though experiments), and many other societies share this belief (see, for example the "Opacity of Mind" special edition of Anthropological Quarterly vol 81:2). I'm interested in whether this is an established component of Nyingma philosophy, or part of a wider philosophical belief in Buddhism?
First of all: this is an excellent question, and deserves a better response than I can give it. I'm far from an expert in Nyingma Buddhism-- among Tibetan traditions, I'm much better read in Gelug texts-- but I'll give it a shot.
The theory of mind that you refer to, that one's thoughts are inaccessible to others, is a mainstay in Western philosophy. A classic explication can be found in Wittgenstein's Beetle Box experiment, and Jacques Derrida (following Levinas's reading of Husserl) has attempted to investigate the ethical implications of the fact that Tout autre est tout autre.
In early Buddhism, the primary soteriological project (and thus Buddhism's raison d'etre) consists largely of the deconstruction of the traditional notion of "self", and the theories of mind proposed are largely subsumed to that project. The "self" is viewed as a collection of five skandhas (heaps, aggregates): form, sensation, perception, mental formations, and consciousness. The relationship between these (and the definition of each term) varies across a number of competing interpretations, but the key factor for our purposes is that each of the above is plural, and represents a flow of discrete events.
In Tibetan Buddhism, this is often conceptualized as a "mind-stream", which is made up of a series of discrete mental events, each of which is linked to the preceding (and succeeding) events (giving the illusion of continuity) by a process of dependent origination. (The fact that a mental event is necessarily caused by a preceding mental event is traditionally given as a proof of rebirth, at least in the Gelug school.) For our purposes, it is important to note that these mental events are necessarily internal: there is no way for someone else to perceive (through ordinary sense perception) these events.
I suppose I should underline that parenthetical qualification; the omniscience of Buddhas (while dwelling in meditative equipoise) is taken as given (and Śāntarakṣita argues this point at length; see Sara McClintock's book on the subject)-- but I assume we are excluding Buddhas here, on practical grounds, at least-- the next Buddha is not expected to arrive in this universe for several billion years, so we can safely table the issue, I think.
Anyway, to return to the matter at hand: the question referred specifically to the Nyingma school, and here we must add some nuance. We have discussed the fact that the "opacity of mind" is near-ubiquitous in both Western philosophy and the Buddhist tradition writ large-- but Nyingma Buddhism is characterized by its (unique) notion of Dzogchen, which is often translated as "radiant mind", and this practice (and the corresponding philosophical interpretations) is the matter of some debate. Nyingmapas (and some Gelugpas) argue that Dzogchen is fully compatible with the Madhyamaka notion of Śūnyatā (Emptiness), but some Gelugpas argue the contrary-- that Dzogchen represents a form of philosophical backsliding which (like some forms of Yogācāra, according to this interpretation) tends toward hypostatization of Mind which opens the way to a reintroduction of Ātman through the back door.
So, to summarize: the "opacity of mind" is not a specifically Nyingma position within Buddhism; in fact, the Nyingma school offers perhaps the best standpoint for an argument against it, if one wished to go down that road (which Buddhists generally don't.)
The idea that you cannot know what another person is thinking (a form of the so-called 'problem of other minds') is certainly unusual in Nyingma philosophy and almost certainly a local idiosyncrasy among Nepalese Nyingmapas. The main Nyingma philosophical writers are Rongzom (1012–1088), Longchenpa (1308-1364), Jamgon Ju Mipham (1846–1912) and Shenga (1871-1927). These writers for the most part held to the traditional madhyamaka views as expounded in India (especially Shenga) where there is no major theme that there is some problem in knowing the minds of others. Rongzom's writings are mostly lost now but there is no evidence he held such a theory. This is basically true of Tibetan Buddhism as a whole, where the problem of 'knowing other minds' and the thoughts (rtog pa) and intentions (bsam pa) of others is barely discussed.
In many Buddhist texts, not unique to the Nyingma or Tibet, it is suggested that Buddhas know the thoughts of others. But the extent to which the minds of others are obscured to ordinary people is nowhere extensively discussed, and it is reasonable to assume minds are opaque just to the extent that, as is obvious, rational agents can hide their motivations or choose not to reveal their thoughts. But it is strange indeed to assume this is the norm, as Ortner seems to imply. In general, we have to assume we 'know' the reasons others have for acting all the time in order to make sense of their behaviour. It is only by doing so that we may consider them to be carrying out actions, whether verbal or physical, rather than behaving mechanically. e.g. See Davidson's 'Three Varieties of Knowledge' for a good discussion. If we did not get the motivations of others right most of the time, it is hard to see how we could have a coherent conception of a reason or motivation at all.
The idea that the reasons of others cannot be known is nowadays widely regarded as philosophically idle in the West, like the idea that we cannot know the external world. It sets the standard of knowledge impossibly high and opens up the doors of global skepticism and solipsism.
