The Yogâcāra thinkers saw that while living beings seem to have no recourse but to carry out their daily lives acting under the assumption that they are experiencing their surrounding environment more or less 'as it really is,' a rigorous and logical examination of the problems concerned with cognition as they are developed through basic Buddhist principles makes the direct experience of 'things-as-they-are' impossible for unenlightened sentient beings. The cognitive problems involved in establishing the relationship between an imputed 'self,' and surrounding objects are investigated by the Yogâcāra school from a variety of perspectives, and in a range of voluminous and detailed texts. But the gist of the problem can be laid out in two central Yogācāric approaches to analyzing the processes of cognition.

The first is that of the four aspects of the cognitive experience. According to Yogâcāra Buddhism, when the cognitive mental functioning is activated, the mind itself is divided, depending upon the particular function, into four aspects, and based on this, that which we know as cognitive function is established. Namely, the mind is divided into the aspects of:

1. that which is seen (objective aspect) 相分
2. that which sees 見分 (subjective aspect);
3. the confirmation of that seeing 自證分 (witnessing aspect); and,
4. the acknowledgment of that confirmation 證自證分 (rewitnessing aspect).

Usually, even in the case where we are firmly convinced that we directly perceive and cognize something that exists outside of the mind, the fact is that it is actually this objective aspect that has been transformed within our minds. In other words, although that which appears in our minds is nothing more than an image resembling that object, we take it to be the actual object of our cognition (for further details, see 四分).

A second basic way that Yogâcāra shows how things cannot, for all practical purposes, exist outside of our consciousness (心外無別法), is through the notion of the three types of subjective transformations 三能變, which are introduced in the short seminal Yogâcāra text called the Triṃśikā Vijñaptimātratāsiddhiḥ (Thirty Verses on Consciousness-only) 唯識三十頌, attributed to Vasubandhu 世親. In this text, Vasubandhu explains how the objects that we perceive are necessarily subjected to transformation by our own consciousnesses, before we have the chance to reflect on them with awareness:

1. The first is the transformation carried out by the storeconsciousness 阿賴耶識 (ālaya-vijñāna) . Since the store consciousness represents the part of our mind that accumulates all the impressions from past experiences, this means that whatever we come across is immediately and subconsciously 'contextualized' by our prior experiences. A vegetable patch is seen quite differently, depending on whether the viewer is a city dweller or a farmer.
2. The second is the transformation carried out by the manas or 'ego' consciousness 末那識. The manas, like the ālaya-vijñāna, is continually active at the subconscious level, but plays the role of continually assessing the value of things in terms of their usefulness to its imaginary self. This means that before a cognitive event has even made its way to the level of conscious awareness, it has already been altered by these two conscious processes.
3. The third is the transformation that occurs at the level of conscious awareness, among the five sensory consciousnesses 前五識 and the sixth, manovijñāna 意識. Sentient beings vary greatly in terms of the capacity of their sensory organs, and cognition is also affected by the sharpness/dullness, or emotional state of the manovijñāna. Having passed through these three transformations, objects are finally consciously taken into awareness and reflected upon.

According to Yogâcāra Buddhism, what we actually perceive are images of the things of the external world as they are transformed by our own consciousness, and reflected onto our own mind. This being so, all of the things around us are the transformations by our own consciousnesses. The problems of accurate and direct cognition of the external world are also addressed in Yogâcāra categories such as the three kinds of objects 三類境, and the three natures 三性. the Mahāyāna-saṃgrāha, for example, says: "All conscious objects are only constructs of consciousness because there are no external objects. They are like a dream." 「如此衆識唯識 以無塵等故 譬如夢等」  〔攝大乘論 T 1593.31.118b12〕 (Keenan 1992: 40).