【明報專訊】IN response to doubts concerning whether Lantau Tomorrow Vision will "deplete the coffers", the government has revealed a preliminary estimate of the cost and returns of the project. The announcement marks the transition of the artificial island initiative from a conceptual to a practical discussion. With no end to ideological disagreements in sight, the government this time has chosen to break from usual practice and reveal cost estimates before completing the related studies. Although concern will inevitably arise regarding whether the figures are accurate or not, initiating practical discussions is, after all, an important starting point. All parties should base their discussion on facts, trying more to cite data and facts rather than engage in vague discussions. Since many Hong Kong infrastructure projects have experienced significant cost overruns in recent years, the public is worried that the same mistakes will be repeated. The authorities must learn the lessons and keep project costs under control. Still, they should not go so far as to give up the long-term planning of infrastructural development because of that potential risk. Hong Kong needs to develop sustainably. For the sake of weighing up the pros and cons of the artificial island proposal, the only way is to launch a feasibility study so as to facilitate an in-depth discussion in society.