Mahayana translate to reflect the idea of a'Great vehicle'- this is because it is Buddhism for the masses. Keown define Mahayana "a major movement in the history of Buddhism embracing many schools in a sweeping reinterpretation of fundamental religious ideals, beliefs and values" and Further says within it there is a "Great emphasis is placed on the twin values of karuna and devoting himself for the service of others".
It can be argued that the basics of Mahayana developed before the second century but much of it developed latter.
Mahayana Buddhism is geographically found in China, Japan, Korea, Tibet. It's basic aspects developed 100bc-100ad but there were many latter second century and beyond developments. It began as a liberal split from conservative pre-Theravadins group and would spread to China via silk road. however, Paul Williams says the "the origins... are obscure in the extreme"- The significance of Mahayana developing in the mainland is that it interacted with Hindu traditions, had to integrate with many different cultural and religious influences, so became more diverse. Their development did Theravada and Mahayana truly split at a 4th council- which were in fact two separate ones. First in Mahayana in Kashmir, Theravada in Sri Lanka (writing down Pali Canon began then) King Kanishka was the Mahayana version of Ashoka- who hosted 4th council and funded the spread of Mahayanin monks. The Mahayanans claim that their teaching is original and according to Denise Cush "Mahayana and non-Mahayana teachings were delivered to different groups of listeners" and that "they were given into the keeping of the nagaspirits until the time was ripe".
One key mahayana developing idea that was before the 2nd century is that of Upaya which means 'skilful means'. A key parable is found in the Lotus sutra written in stages 50 to 150 AD demonstrates upaya as the Parable of the Burning House- wherte the key moral is that of skilful lying. However, another key developing idea was that of the the Trikaya doctrine or the '3 bodies' doctrine of the Buddha which developed under the latter third century Yogacara school. It teachings theres is a 1. Teaching body 'dharmakaya' of the Buddha, a 2. Actual body 'nirmanakaya'of the Buddha, and a 3. Celestial body 'sambhogakaya' of teh Buddha. Yogacara and those that followed like teh Tibetian thinkers developed the idea of the Dharmakaya or the enlightened mind, purified consciousness and beyond words. The idea is that Buddha has always existed which is why we all have Buddha-nature. The Nirmanakaya is the physical manifestation of an enlightened being, can refer to the historical Buddha and the Sambhogakaya is the dimension of energy and light in which enlightened beings can choose to reside in. In this state Buddhas/Bodhisattvas are intangible but visible, like a rainbow.
In latter centuries the idea of the that there are 5 cosmic Buddhas each who reign over their own Buddha worlds developed. A Basham said about the Trikaya doctrine that "The Buddha had 3 bodies, the body of essence, the body of bliss and the transformation body" furtehr that "the body of essence was identified with... the Brahman of the Upanishads".
However much of the Mahayana version of the eightfold path is the Bodhisattva path can be found in the Perfection of wisdom literature that predates the 2nd century. A key part of it is the Bodhisattva vow "however innumerable sentient beings are, I vow to save them". this is take that you can develop Bodhicitta the desire to liberate oneself and all others from suffering. versions of it go back to the 800 verses 100 BC. The goal of the Bodhisattva path is explained as dull Buddhahood but that nirvana not enough for Mahayana. Nirvana and Samsara according to Sponberg were thought are co-eternal and co-terminus, so they exist together- this means you have not truly escaped until you reach Buddhahood. From the start there were examples of Bodhisattvas that are worshipped such as Avalokiteshvara (represents compassion in general, Dalai Lama is said to be an emanation of) and Mantreya (next human Buddha) and latter the Tara's developed in Tibetian devotional practices. (represents feminine compassion).
In conclusion while Mahayana claims to discover the higher and more perfected teachings of the Buddha in reality these developed over a 500 hundred year period both before and after the year 200 AD.
Over both Theravada and Mahayana schools of Buddhism, enlightenment can be understood in many different ways. One popular view in Mahayana schools is the idea that enlightenment is the ability to truly live in the present moment, without being fettered by influence from past actions or worry about the future. While this is a key part of Mahayana thought towards enlightenment, I feel that saying enlightenment is only this is incorrect, as it fails to reflect on Theravada views towards enlightenment, such as the cessation of desire and suffering, or the concept of exstasis, that being enlightenment as a wholly different state to experience.
While it is clear that enlightenment is not only learning to live in the moment, it is true that this idea is central in Buddhist thinking towards enlightenment. This is particularly seen in Mahayana thought, as the basic teaching is one which is intended to help the majority of the Buddhist Sangha reach enlightenment, in line with the Mahayana schools aiming to be the 'greater vehicle' for followers, both in the monastic orders and the laity. This is seen in the simple message and goal, that of appreciating each emotion as it come and goes. This simple theory is easy to understand, and therefore could be seen as the only important part of enlightenment, as it is the component which, once realised, will allow follower to reach nirvana.
This thought is sustained by the Buddha himself, as in "a mind unruffled by the vagaries of fortune, from sorrow freed ... is the greatest blessing". Here we see in buddhacava the importance of having a mind simply focussed on the present is, in the words of the Buddha "the greatest blessing", clearly presenting the importance of this aspect of enlightenment, however I do not feel that it justifies the statement that it is the only aspect of enlightenment. More evidence that could justify the statement is that it helps Mahayana Buddhists realize the purpose of the Bodhisattvas- ones who have reached enlightenment yet refrain from passing into the next mode of existence due to a universal compassion (known as metta) for all other beings.
This omnibenevolent mode of living is enabled by the ability to focus purely on how to help others in the present moment, without being fettered by the past or future. This purpose of enlightenment is a keystone of Mahayana Buddhism, recited weekly in by Tibetan Buddhists in the 'Refuge Prayer': "May I attain Buddhahood for the sake of all sentient beings". Therefore one can clearly see how enlightenment's true form as the ability to live truly in the moment is correct, as from it stems forth the other important aspect of Buddhist teachings. However, I disagree with the statement, as there are several other aspects of enlightenment clearly established by both Theravada and Mahayana schools of thought. One other pOint which propagates living in the moment as the only element of enlightenment is the Theravada point that enlightenment grants freedom from the Cycle of Samsara. Surely if this is the case, then living in the moment is the only aspect of enlightenment that matters, as it provides a liberation from suffering, with those Arhats and Bodhisattvas who have reached enlightenment free from concern about their past and futures, with karmic debt no longer applying to them, a clear purpose of enlightenment in Theravada Buddhism- as noted in "attachment is the root of all suffering" and "all conditioned experience is unsatisfying". This keystone of Buddhist thought can therefore be traced back to the granting of the ability to truly live in the moment, leading some to declare that this is the essential element of enlightenment, however I disagree as this statement does not reflect the diaspora of responses towards enlightenment seen in the different schools and interpretations of Buddhism.
One other aspect of enlightenment that is put forward by Theravada buddhists is that a major element of enlightenment is 'snuffing out the flames of desire', a concept which is not covered by the idea of living in the moment, and therefore contradictory to the statement. The 'snuffing out', in this case' refers to the removal of the '3 poisons'- moha (ignorance), raga (greed) and dvesha (ill will). By removing these and instead adhering to the 5 precepts of a good Buddhist life, the potential to reach nirvana is found. This adheres to the basic teachings of the Buddha, such as "Conquer anger with non-anger. Conquer badness with goodness", and in doing so surely disproves the statement, as this snuffing out of desire is something which cannot be filed under the category of "living in the moment". It is then easy to see how one can declare the statement false, as it fail to realise this Theravada viewpoint on what enlightenment means, something which can be perhaps put down to the bias of Karen Armstrong towards the Mahayana school. This way of thinking can help Arhats reach nirvana and complete their spiritual journey, with the Dhammapada establishing this teaching as important in "There is no fear for one whose mind is not filled with desires", again an idea which expands upon the unilateral statement of 'living in the moment', proving it wrong in my opinion. Another area of enlightenment which is important for both Mahayana and Theravada schools is the idea of 'exstasis', meaning 'to stand outside oneself'. This view of enlightenment as a transcendent experience, wholly different to regular life is also seemingly ignored by the statement, another reason to declare it false. This is key particularly in Mahayana schools such as Pure Land Buddhism, with scholars such as Shinran noting that "an ordinary person cannot be enlightened, but can realise it in the land of serene sustenance"- here acknowledging this other state which enlightenment is so deeply interlinked with. If Shinren is correct and the only way to true enlightenment is to reach this state, one can hardly agree with the statement due to its failure to recognise this element of enlightenment. Additionally, this teaching as a base can then lead onto the core theology of other Mahayana teachings, such as the idea that reaching enlightenment is to realise the true nature of the mind, as explained by teachers like Bakei, in "unborn and un perishable is the original mind". This line of thought is also blatantly ignored by the statement, making it easy to declare it unhelpful in understanding Buddhism as it fails to recognise many key ideas of enlightenment.
To conclude, the statement is clearly false as it fails to acknowledge many keystones of both Mahayana and Theravada understanding of what is enlightenment, ignoring ideas of exstasis and the essential theory of snuffing out desire in Theravada thought, leaving the statement somewhat lacking in providing a full understanding of what is enlightenment. While the idea of "living in the moment" does have some value as it forms the basis of enlightenment thought in some Mahayana schools, and leads onto enabling teachings such as universal compassion, one can conclude that the statement is false as the majority of Buddhists would say that this definition of enlightenment does not sufficiently cover their views.