Sartre, in the opening chapter of his very challenging read, Being and Nothingness, cleaves existence neatly in two; what he calls being-for-itself and being-in-itself.
The in-itself is being. I don’t recall Sartre ever explicitly describing it as physical matter, but that is basically what it amounts to. The in-itself is characterised by three features: 1) it is in-itself, 2) it is what it is, and 3) it is. Respectively, these mean: 1) the in-itself is independent; i.e. it doesn’t depend on anything else to exist, 2) it doesn’t refer to itself; i.e. it isn’t self-reflexive, and 3) it is neither possible nor necessary. It isn’t necessary because it didn’t have to be, but neither is it possible because inert, non-conscious matter has no possibilities.
The for-itself, on the other hand, is consciousness. What does this mean? Consciousness is precisely not being. It is an empty, ‘massless’ perspective on, or relation to, being. The for-itself cannot be grasped because it is not a being, it’s not a thing, it is precisely no-thing… which is not the same as saying it is an illusion or that it doesn’t exist at all. If you find this scientifically implausible, I challenge you to describe consciousness in a way that preserves what conscious clearly is, all while staying within the confines of naturalistic materialism.
The for-itself, as the locus of subjective experience, is what brings value and meaning to the universe. Without it, the universe really would be nothing more interesting than atom-sized billiard balls smacking into each other. However, there is a problem with the for-itself; namely, it lacks the certainty and ‘fullness’ that comes with being. As something as insubstantial as a perspective or a relation, it is consigned to an ambiguous existence, never attaining a ‘full’, or ‘pure’, being. It is never wholly ‘this’ or ‘that’ thing, for if it were, it would immediately cease to be consciousness and become in-itself instead.
The for-itself is aware of this lack (a lack of being) which lies at its heart and so desires to overcome it. One way it could do this would be to simply become in-itself, thereby attaining the full plenitude and certainty that the in-itself enjoys. However, doing this would mean it would no longer be consciousness, which would therefore be equivalent to self-annihilation. It would have achieved ‘being’ but at the cost of being able to know itself as being. It therefore desires to become in-itself while at the same time preserving itself as for-itself. It desires to be in-itself-for-itself.
The problem with this solution, however, is that it is impossible. The in-itself and the for-itself are complete ontological opposites. Nevertheless, this desire isn’t something we can one day simply slough off. It is a core part of what it means to be human and it’s in this context that Sartre says, man is a useless passion.”
Meditation in Buddhism is specifically practiced to ‘train’ the mind so that it is not being continually pulled into imaginary wanderings or flights of fancy. Ultimately, the idea is to detach from what Buddhism sees as illusory, insubstantial distractions. Observe the ceaseless chatter of the mind but do so from a distance without getting caught up in the individual thoughts it sweeps your way. In fact, these thoughts are consistently portrayed in Buddhist literature in negative terms. One Buddhist meditator I heard once compared thoughts to noisy children demanding his attention and if he simply ignored them (or looked at them and ‘let them go’, as the euphemism might have it) for long enough, they would eventually leave him in peace. Why does Buddhism advocate this? Well, aside from the fact that our thoughts are the source of all suffering, you, the real you (whatever that might mean), isn’t having them. If you pay attention, Buddhism teaches, you will see that thoughts just arise by themselves (this is actually the point of meditation, to see how the mind ticks along without you). Thoughts are like commentary running in the background. We typically identify with them but, the claim goes, you can break this illusion if you look closely enough.
Of course, the ultimate goal of Buddhism, enlightenment, is a supposed, elevated state of mind in which one has achieved complete and permanent liberation from all illusory beliefs and phenomena, including the belief in the existence of a self and the belief that the external world is real. This magical state allows one to live out the remainder of one’s days in perfect calm, still noticing thoughts and desires as they arise perhaps, but certainly no longer attaching to them, living beyond, or above, them, as it were.
Buddhism and Sartre
It strikes me that Sartre’s goal of the in-itself-for-itself is not overly dissimilar to these Buddhist ideals. There are at least two points of contact between them. First, Buddhism sees thoughts as the enemy. The ideal meditative state is achieved when one has either detached from one’s thoughts or stilled them completely. Now, in a way, thoughts are like the currency of the for-itself. They account for its capacity to exist as non-being, as never ‘this’ or ‘that’ thing, precisely because I can always conceive (think) of myself as the opposite. In essence, the idea of non-attachment in Buddhism amounts to a rejection, or dismissal, of thoughts as superfluous, or at the very least, as not coming from you. Get rid of them, or break the illusion that you are them, and what do you have left? Well, something that is a little bit less of a relation, a little bit less of a for-itself, and a little bit more of an in-itself.
Second, the permanent liberation enlightenment promises can hardly be more aptly conceived in terms other than Sartre’s in-itself. The Buddhist arahant (the term in Theravada Buddhism for someone who has attained nirvana) no longer experiences that ambiguity in being we talked about earlier. Of course, this isn’t to suggest that he or she knows everything or never experiences doubt; but there is some part of them, a disposition, an attitude, a part of their character, whatever you want to call it, which is fixed, which no longer suffers from that uneasy ambiguity that pervades the for-itself. A part of them which is, in other words, in-itself.
These two points suggest ways in which Buddhism tends to value modes of being that correspond to Sartre’s idea of the in-itself, but this hasn’t quite gotten us to our goal yet. What takes us all the way is when we realise that, while the Buddhist aspires to these in-itself ideals, she does so while at the same time trying to maintain herself as being-for-itself. In short, she attempts to make herself into an in-itself-for-itself. She wants the security, the completeness, the plenitude of being, that being in-itself confers but she doesn’t want to give up the consciousness that would allow her to know herself in this way. Unfortunately, this renders Buddhism, as far as the two ideals discussed here anyway, a useless passion.
 Sartre never uses this crude materialistic term. I only throw it in here because, while a modern mind may balk at the idea of consciousness as nothing, modern physics has paved the way with its insistence that some ‘particles’ have no mass.
 Although they are also the source of all happiness.
 This isn’t the same as idealism. Buddhism doesn’t teach that the world is mental. However, it does hold that reality is constructed, not perceived. In being constructed, we aren’t perceiving reality as it really is. In this sense, reality, as most of us perceive it, is deemed to be an illusion.