The most basic activ­i­ty of every per­son, occur­ring con­stant­ly in a person’s life, is cog­ni­tion of sense impres­sions by way of the eye, ear, nose, tongue, body, and mind. With cog­ni­tion there is an accom­pa­ny­ing sen­sa­tion, of either plea­sure, pain, or a neu­tral feel­ing. With the aris­ing of such sen­sa­tions there are reac­tions in the mind: if the object is pleas­ant there aris­es desire and delight; if the object is unpleas­ant or painful there aris­es annoy­ance and aver­sion. With delight a per­son wants to repeat the expe­ri­ence or wants to obtain some­thing. With aver­sion the per­son wish­es to avoid the expe­ri­ence or wish­es to get rid of or elim­i­nate some­thing. This process occurs con­tin­u­al­ly; some expe­ri­ences are faint and pass by with­out a per­son tak­ing notice, while oth­er expe­ri­ences are pow­er­ful and pro­nounced, with a clear impact on the mind and with long-last­ing con­se­quences. These pow­er­ful or unset­tling expe­ri­ences tend to gen­er­ate pro­tract­ed, pro­lif­er­at­ed think­ing. If these thoughts do not cease in the mind they erupt as ver­bal and phys­i­cal actions, both minor and major. Small, seem­ing­ly insignif­i­cant events and process­es occur­ring in people’s lives can thus have an impor­tant effect on how they live, the roles they play in soci­ety, and on human interactions.

From the per­spec­tive of wis­dom, allow­ing the mind to blind­ly fol­low the process described above, of delight­ing in plea­sure and being annoyed by pain, acts as an imped­i­ment and pre­vents dis­cern­ment of things as they tru­ly are. This is because the mind when giv­en free reign with­out restraint has the fol­low­ing characteristics:

• The mind gets stuck at such delight and aver­sion; it falls under the sway of attach­ment or aver­sion; it is obstruct­ed by likes and dis­likes; it sees things from a biased per­spec­tive, not accord­ing to how they tru­ly are.
• The mind falls into the past or projects itself into the future; when a per­son expe­ri­ences a sense impres­sion and either delight or aver­sion aris­es, the mind gets stuck at the point or fea­ture that he finds agree­able or dis­agree­able. He then cre­ates a men­tal image of these agree­able or dis­agree­able fea­tures, har­bours this image, and cre­ates all sorts of fan­ci­ful ideas about it. Get­ting stuck at agree­able or dis­agree­able fea­tures and cling­ing to men­tal images of an object is equiv­a­lent to slip­ping into the past; and a pro­lif­er­a­tion of thoughts about this object is equiv­a­lent to drift­ing off into the future. A person’s under­stand­ing of the object—the mind-cre­at­ed images based on likes and dis­likes, or the embell­ished ideas about the object—is not an under­stand­ing of the object as it tru­ly exists in that moment.
• The mind is sub­ject to pro­lif­er­at­ed think­ing, which inter­prets the object of cog­ni­tion or the expe­ri­ence accord­ing to one’s upbring­ing or ingrained habits: accord­ing to cher­ished views, opin­ions, and val­ues. The mind is at the mer­cy of these pro­lif­er­a­tions; it is unable to see things objec­tive­ly and pure­ly as they are.
• Besides being swayed by pre-exist­ing men­tal bias­es and habits, the mind adds the embell­ished men­tal images stem­ming from new expe­ri­ences to these bias­es and habits, thus com­pound­ing them.

These men­tal process­es are not lim­it­ed to just coarse and super­fi­cial aspects of a person’s life. The Bud­dhist teach­ings empha­size the impaired work­ings of the mind on a refined, sub­tle lev­el, which lead unawak­ened peo­ple to see things as sta­ble, sol­id, and inher­ent­ly beau­ti­ful or loath­some, to attach to var­i­ous con­ven­tion­al real­i­ties, and to over­look the all-encom­pass­ing law of causal­i­ty. These men­tal process­es are deeply ingrained in the mind as habits and ten­den­cies which peo­ple have accu­mu­lat­ed over a long peri­od of time, even since birth—for twen­ty, thir­ty, forty, fifty years or more—and many peo­ple have not devel­oped any train­ing in cut­ting the cycle of these habits. Deal­ing with and rec­ti­fy­ing this sit­u­a­tion is thus not easy. At the moment of receiv­ing a sense impres­sion, if a per­son does not estab­lish mind­ful­ness and curb the habit­u­al ten­den­cies, the mind will auto­mat­i­cal­ly fol­low the course of habit. Solv­ing this prob­lem is not only a mat­ter of cut­ting the cycle of react­ing through delight and aver­sion and of pro­lif­er­at­ed think­ing, but is also a mat­ter of mod­i­fy­ing the pow­er­ful surges of habit and per­son­al dis­po­si­tion. Mind­ful­ness is an essen­tial fac­tor for clear­ing the way and for mar­shal­ing oth­er forces in respect to both cut­ting the cycle of reac­tiv­i­ty and alter­ing habits. Prac­tice in accord with the Four Foun­da­tions of Mind­ful­ness has this objec­tive: when mind­ful­ness keeps pace with expe­ri­ence in every moment and sees things as they tru­ly are, it is both able to erad­i­cate unwhole­some men­tal cycles and to mod­i­fy old habits, along with cul­ti­vat­ing new modes of men­tal behaviour.

(An excerpt from chap­ter 16 of Ven­er­a­ble Phra Payut­to’s book Bud­dhad­ham­ma, on the Path fac­tors of men­tal collectedness.)