Two conferences this weekend at Carnegie Mellon University will require some tough choices by those interested in the arts and in ideas.

"[Im]Permanence: Cultures In/Out of Time," sponsored by CMU's Center for the Arts in Society, opens at 2 p.m. Thursday with a performance by Srishti Dances of India in McConomy Auditorium University Center.

The keynote address, "Einstein in Time," will be given Friday night at 8 by Alan Lightman, MIT phycisist and novelist. The conference concludes with a brunch from 10:30 a.m. to noon Sunday in the College of Fine Arts.

The interdisciplinary, international conference will feature visual and performing arts practitioners, humanities scholars, and curation and preservation experts who will discuss past and present relationships between art and time.

Topics will include permanence, ephemera, cultural continuity and opinions about preservation. Special exhibitions and performances are scheduled for conference weekend.

The broad range of presenters include Howard Meltzer, CUNY Manhattan, on "Constant Change, Constant Identity: Music's Ontology"; Libby Escobedo, Princeton, on "Continuity and Transformation in Anglo-Saxon England: Re-use and Re-interpretation of Burial Sites as Holy Places"; filmmakers Jeffrey Martin and Stephanie Maxwell on their work; and Terrence Smith, University of Pittsburgh, "What Kinds of Time Does Contemporary Art Take?"

For a conference schedule, fees or to register, go to www.hss.cmu.edu/cas/Content/Conference.htm.

Shifting paradigms

"Shifting the Paradigm: The Groundworks Monongahela Conference" begins at 9:15 a.m. Saturday with a keynote address by Tom Finkelpearl, author of "Dialogues in Public Art" and director of the Queens Museum of Art.

The conference, sponsored by CMU's STUDIO for Creative Inquiry and the Regina Gouger Miller Gallery, will address the artist's role in contemporary society, including involvement in "creating or manifesting social change."

National and international speakers will address four topics -- trails, parks, water planning and land planning -- and be responded to by local officials, experts and activists.

Closing remarks will be presented at 4:30 p.m. Sunday by Grant Kester, author of "Conversation Pieces: Community and Communication in Modern Art."

The conference is free, but seating is limited and registration is required at 3r2n.cfa.cmu.edu/groundworks/conference.

It will be held at the Miller Gallery, which opens the related exhibition "Groundworks: Environmental Collaboration in Contemporary Artz" this weekend.

For information, contact studio-info@andrew.cmu.edu or 412-268-3454.