The Bodhisattvas may attain their highest by the fourfold knowledge of (1) _svacittad@rs'hyabhâvanâ_, (2) _utpâdasthitibha@ngavivarjjanatâ_, (3) _bâhyabhâvâbhâvopalak@sa@natâ_ and (4) _svapratyâryyajñânâdhigamâbhinnalak@sa@natâ_. The first means that all things are but creations of the imagination of one's mind. The second means that as things have no essence there is no origination, existence or destruction. The third means that one should know the distinctive sense in which all external things are said either to be existent or non-existent, for their existence is merely like the mirage which is produced by the beginningless desire (_vâsanâ_) of creating and perceiving the manifold. This brings us to the fourth one, which means the right comprehension of the nature of all things. The four dhyânas spoken of in the _Lankâvatâra_ seem to be different from those which have been described in connection with the Theravâda Buddhism. These dhyânas are called (1) _bâlopacârika_, (2) _arthapravichaya_, (3) _tathatâlambana_ and (4) _tathâgata_. The first one is said to be that practised by the s'râvakas and the pratyekabuddhas. It consists in concentrating upon the doctrine that there is no soul (_pudgalanairâtmya_), and that everything is transitory, miserable and impure. When considering all things in this way from beginning to end the sage advances on till all conceptual knowing ceases (_âsa@mjñânirodhât_); we have what is called the vâlopacârika dhyâna (the meditation for beginners). The second is the advanced state where not only there is full consciousness that there is no self, but there is also the comprehension that neither these nor the doctrines of other heretics may be said to exist, and that there is none of the dharmas that appears. This is called the _arthapravicayadhyâna_, for the sage concentrates here on the subject of thoroughly seeking out (_pravichaya_) the nature of all things (_artha_). The third dhyâna, that in which the mind realizes that the thought that there is no self nor that there are the appearances, is itself the result of imagination and thus lapses into the thatness (_tathatâ_). This dhyâna is called _tathatâlambana_, because it has for its object tathatâ or thatness. The last or the fourth dhyâna is that in which the lapse of the mind into the state of thatness is such that the nothingness and incomprehensibility of all phenomena is perfectly realized; 151