(1) The doctrine that there are mental presentations which necessarily refer to external things is not only bad natural science; it is also bad phenomenology and conceptual confusion.(2) Heidegger grounded his philosophy in phenomenology , the close examination of the given field of immediate experience.(3) A phenomenology of consciousness, then, explores neither the metaphysical composition nor the causal genesis of things, but the ‘constitution’ of their meaning.(4) The phenomenology of claims of good and right are also distinct: the good attracts or appeals, whereas claims of right appear to command authority.(5) Extensive studies of LSD phenomenology were performed in clinical and experimental psychiatric and psychological research.(6) For such reasons as these Heidegger believes that ontology and phenomenology coincide.(7) In origin, as described by philosopher Edmund Husserl, phenomenology is the intuitive appreciation of phenomena as they are immediately perceived, without reference to scientific theory or prior learning.(8) Husserl's phenomenology is Derrida's most immediate philosophical heritage.(9) According to Van Manen, the aim of interpretive phenomenology is to gain a deeper understanding of the nature or meaning of our everyday experiences.(10) He appears to be uncomfortably situated in the difference between Husserl and Heidegger's phenomenology , which heralded ‘the return to the things themselves’.(11) But if externalism can be defined broadly enough to encompass Heidegger, Merleau-Ponty, Kripke, and Burge, still the comparison is strained when we take account of the different sources of ‘externalism’ in the phenomenologists .(12) His philosophy teachers included Erich Rothacker, Oskar Becker (a phenomenologist influenced both by Husserl and Heidegger), and the neo-Hegelian Theodor Litt.(13) Consider first the predicted outcomes for people who can develop an altered state, as defined phenomenologically and neurologically.(14) Martin Heidegger, a German philosopher, has been variously classified as a phenomenologist , an existentialist, and a mystic.(15) A close link between phenomenology and hermeneutics has resulted in the interchangeable use of the terms; however, philosophical beliefs differ among phenomenologists and hermeneutic philosophers.(16) Unlike Piazza San Marco, it is spatially infinite and phenomenologically abstract, untouched by the effects of climate, time, seasons, geography or physical humanity.