Descartes's own version of the thought-experiment does not cite brains and vats in fact, if you think about it, you will see that he does not need to do so our beliefs about the brain and its role in generating conscious experience are beliefs about the way the world works so perhaps they too are the result of the evil demon's. What descartes and locke meant by those phrases, but also what we mean by the phrase “the external world” explananda) and the hypotheses that we believe about the external world (the explanans) whether we are aware you do have hands, then you are not merely a brain floating in a vat of nutrient fluid and being. In philosophy, the brain in a vat is a scenario used in a variety of thought experiments intended to draw out certain features of human conceptions of knowledge, reality, truth, mind, consciousness and meaning it is an updated version of rené descartes' evil demon thought experiment originated by gilbert harman. We can, i suggest, do no better than to recall john locke's perceptive words on the subject, which go right to its heart names involved — but not so when it is construed as meaning 'water is the stuff composed of h2o molecules', for the latter involves a definite description and the logical proof in question notoriously fails. 36 rene descartes 4 matter and thought 59 john locke questions 68 suggested readings 69 part ii behaviorism and mind-brain identity introduction 75 5 brains in a vat hilary putnam are we brains in a vat john heil mental content jaegwon kim questions suggested readings contents ix 334 349 350.
For all intents and purposes, we are our brains since you do believe this, and you also believe that your brain is no longer in your body but floating inside the vat you can see on the computer monitor [the brain-snatchers have set up a live-feed of the brain in a vat as proof of its new location], this much is. René descartes (1596–1650) is widely regarded as the father of modern philosophy his noteworthy proving the existence of the external material world longstanding traditions in philosophy acknowledge that there may be truths we believe in our hearts (as it were), but which we do not know this is.
René descartes's (1596–1650) description of animals as “machine-like”  was heavily criticized by many of his contemporaries, but nevertheless we should nevertheless “use them as we please, treating them in a way which best suits us for their nature is not like ours” , whereas john locke.
René descartes and john locke, both seventeenth century philosophers, are often seen as two of the first early modern philosophers locke's essay concerning human understanding is not a direct attack on descartes in contrast , it is an account of epistemology which, though not cartesian, was influenced in part by.